text:
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global = global || self, global.less = factory());
}(this, (function () { 'use strict';

  // Export a new default each time
  var defaultOptions = (function () { return ({
      /* Inline Javascript - @plugin still allowed */
      javascriptEnabled: false,
      /* Outputs a makefile import dependency list to stdout. */
      depends: false,
      /* (DEPRECATED) Compress using less built-in compression.
    * This does an okay job but does not utilise all the tricks of
    * dedicated css compression. */
      compress: false,
      /* Runs the less parser and just reports errors without any output. */
      lint: false,
      /* Sets available include paths.
    * If the file in an @import rule does not exist at that exact location,
    * less will look for it at the location(s) passed to this option.
    * You might use this for instance to specify a path to a library which
    * you want to be referenced simply and relatively in the less files. */
      paths: [],
      /* color output in the terminal */
      color: true,
      /* The strictImports controls whether the compiler will allow an @import inside of either
    * @media blocks or (a later addition) other selector blocks.
    * See: https://github.com/less/less.js/issues/656 */
      strictImports: false,
      /* Allow Imports from Insecure HTTPS Hosts */
      insecure: false,
      /* Allows you to add a path to every generated import and url in your css.
    * This does not affect less import statements that are processed, just ones
    * that are left in the output css. */
      rootpath: '',
      /* By default URLs are kept as-is, so if you import a file in a sub-directory
    * that references an image, exactly the same URL will be output in the css.
    * This option allows you to re-write URL's in imported files so that the
    * URL is always relative to the base imported file */
      rewriteUrls: false,
      /* How to process math
    *   0 always           - eagerly try to solve all operations
    *   1 parens-division  - require parens for division "/"
    *   2 parens | strict  - require parens for all operations
    *   3 strict-legacy    - legacy strict behavior (super-strict)
    */
      math: 0,
      /* Without this option, less attempts to guess at the output unit when it does maths. */
      strictUnits: false,
      /* Effectively the declaration is put at the top of your base Less file,
    * meaning it can be used but it also can be overridden if this variable
    * is defined in the file. */
      globalVars: null,
      /* As opposed to the global variable option, this puts the declaration at the
    * end of your base file, meaning it will override anything defined in your Less file. */
      modifyVars: null,
      /* This option allows you to specify a argument to go on to every URL.  */
      urlArgs: ''
  }); });

  function extractId(href) {
      return href.replace(/^[a-z-]+:\/+?[^\/]+/, '') // Remove protocol & domain
          .replace(/[\?\&]livereload=\w+/, '') // Remove LiveReload cachebuster
          .replace(/^\//, '') // Remove root /
          .replace(/\.[a-zA-Z]+$/, '') // Remove simple extension
          .replace(/[^\.\w-]+/g, '-') // Replace illegal characters
          .replace(/\./g, ':'); // Replace dots with colons(for valid id)
  }
  function addDataAttr(options, tag) {
      for (var opt in tag.dataset) {
          if (tag.dataset.hasOwnProperty(opt)) {
              if (opt === 'env' || opt === 'dumpLineNumbers' || opt === 'rootpath' || opt === 'errorReporting') {
                  options[opt] = tag.dataset[opt];
              }
              else {
                  try {
                      options[opt] = JSON.parse(tag.dataset[opt]);
                  }
                  catch (_) { }
              }
          }
      }
  }

  var browser = {
      createCSS: function (document, styles, sheet) {
          // Strip the query-string
          var href = sheet.href || '';
          // If there is no title set, use the filename, minus the extension
          var id = "less:" + (sheet.title || extractId(href));
          // If this has already been inserted into the DOM, we may need to replace it
          var oldStyleNode = document.getElementById(id);
          var keepOldStyleNode = false;
          // Create a new stylesheet node for insertion or (if necessary) replacement
          var styleNode = document.createElement('style');
          styleNode.setAttribute('type', 'text/css');
          if (sheet.media) {
              styleNode.setAttribute('media', sheet.media);
          }
          styleNode.id = id;
          if (!styleNode.styleSheet) {
              styleNode.appendChild(document.createTextNode(styles));
              // If new contents match contents of oldStyleNode, don't replace oldStyleNode
              keepOldStyleNode = (oldStyleNode !== null && oldStyleNode.childNodes.length > 0 && styleNode.childNodes.length > 0 &&
                  oldStyleNode.firstChild.nodeValue === styleNode.firstChild.nodeValue);
          }
          var head = document.getElementsByTagName('head')[0];
          // If there is no oldStyleNode, just append; otherwise, only append if we need
          // to replace oldStyleNode with an updated stylesheet
          if (oldStyleNode === null || keepOldStyleNode === false) {
              var nextEl = sheet && sheet.nextSibling || null;
              if (nextEl) {
                  nextEl.parentNode.insertBefore(styleNode, nextEl);
              }
              else {
                  head.appendChild(styleNode);
              }
          }
          if (oldStyleNode && keepOldStyleNode === false) {
              oldStyleNode.parentNode.removeChild(oldStyleNode);
          }
          // For IE.
          // This needs to happen *after* the style element is added to the DOM, otherwise IE 7 and 8 may crash.
          // See http://social.msdn.microsoft.com/Forums/en-US/7e081b65-878a-4c22-8e68-c10d39c2ed32/internet-explorer-crashes-appending-style-element-to-head
          if (styleNode.styleSheet) {
              try {
                  styleNode.styleSheet.cssText = styles;
              }
              catch (e) {
                  throw new Error('Couldn\'t reassign styleSheet.cssText.');
              }
          }
      },
      currentScript: function (window) {
          var document = window.document;
          return document.currentScript || (function () {
              var scripts = document.getElementsByTagName('script');
              return scripts[scripts.length - 1];
          })();
      }
  };

  var addDefaultOptions = (function (window, options) {
      // use options from the current script tag data attribues
      addDataAttr(options, browser.currentScript(window));
      if (options.isFileProtocol === undefined) {
          options.isFileProtocol = /^(file|(chrome|safari)(-extension)?|resource|qrc|app):/.test(window.location.protocol);
      }
      // Load styles asynchronously (default: false)
      //
      // This is set to `false` by default, so that the body
      // doesn't start loading before the stylesheets are parsed.
      // Setting this to `true` can result in flickering.
      //
      options.async = options.async || false;
      options.fileAsync = options.fileAsync || false;
      // Interval between watch polls
      options.poll = options.poll || (options.isFileProtocol ? 1000 : 1500);
      options.env = options.env || (window.location.hostname == '127.0.0.1' ||
          window.location.hostname == '0.0.0.0' ||
          window.location.hostname == 'localhost' ||
          (window.location.port &&
              window.location.port.length > 0) ||
          options.isFileProtocol ? 'development'
          : 'production');
      var dumpLineNumbers = /!dumpLineNumbers:(comments|mediaquery|all)/.exec(window.location.hash);
      if (dumpLineNumbers) {
          options.dumpLineNumbers = dumpLineNumbers[1];
      }
      if (options.useFileCache === undefined) {
          options.useFileCache = true;
      }
      if (options.onReady === undefined) {
          options.onReady = true;
      }
      if (options.relativeUrls) {
          options.rewriteUrls = 'all';
      }
  });

  /*! *****************************************************************************
  Copyright (c) Microsoft Corporation. All rights reserved.
  Licensed under the Apache License, Version 2.0 (the "License"); you may not use
  this file except in compliance with the License. You may obtain a copy of the
  License at http://www.apache.org/licenses/LICENSE-2.0

  THIS CODE IS PROVIDED ON AN *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
  WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
  MERCHANTABLITY OR NON-INFRINGEMENT.

  See the Apache Version 2.0 License for specific language governing permissions
  and limitations under the License.
  ***************************************************************************** */
  /* global Reflect, Promise */

  var extendStatics = function(d, b) {
      extendStatics = Object.setPrototypeOf ||
          ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
          function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
      return extendStatics(d, b);
  };

  function __extends(d, b) {
      extendStatics(d, b);
      function __() { this.constructor = d; }
      d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
  }

  function __spreadArrays() {
      for (var s = 0, i = 0, il = arguments.length; i < il; i++) s += arguments[i].length;
      for (var r = Array(s), k = 0, i = 0; i < il; i++)
          for (var a = arguments[i], j = 0, jl = a.length; j < jl; j++, k++)
              r[k] = a[j];
      return r;
  }

  var colors = {
      'aliceblue': '#f0f8ff',
      'antiquewhite': '#faebd7',
      'aqua': '#00ffff',
      'aquamarine': '#7fffd4',
      'azure': '#f0ffff',
      'beige': '#f5f5dc',
      'bisque': '#ffe4c4',
      'black': '#000000',
      'blanchedalmond': '#ffebcd',
      'blue': '#0000ff',
      'blueviolet': '#8a2be2',
      'brown': '#a52a2a',
      'burlywood': '#deb887',
      'cadetblue': '#5f9ea0',
      'chartreuse': '#7fff00',
      'chocolate': '#d2691e',
      'coral': '#ff7f50',
      'cornflowerblue': '#6495ed',
      'cornsilk': '#fff8dc',
      'crimson': '#dc143c',
      'cyan': '#00ffff',
      'darkblue': '#00008b',
      'darkcyan': '#008b8b',
      'darkgoldenrod': '#b8860b',
      'darkgray': '#a9a9a9',
      'darkgrey': '#a9a9a9',
      'darkgreen': '#006400',
      'darkkhaki': '#bdb76b',
      'darkmagenta': '#8b008b',
      'darkolivegreen': '#556b2f',
      'darkorange': '#ff8c00',
      'darkorchid': '#9932cc',
      'darkred': '#8b0000',
      'darksalmon': '#e9967a',
      'darkseagreen': '#8fbc8f',
      'darkslateblue': '#483d8b',
      'darkslategray': '#2f4f4f',
      'darkslategrey': '#2f4f4f',
      'darkturquoise': '#00ced1',
      'darkviolet': '#9400d3',
      'deeppink': '#ff1493',
      'deepskyblue': '#00bfff',
      'dimgray': '#696969',
      'dimgrey': '#696969',
      'dodgerblue': '#1e90ff',
      'firebrick': '#b22222',
      'floralwhite': '#fffaf0',
      'forestgreen': '#228b22',
      'fuchsia': '#ff00ff',
      'gainsboro': '#dcdcdc',
      'ghostwhite': '#f8f8ff',
      'gold': '#ffd700',
      'goldenrod': '#daa520',
      'gray': '#808080',
      'grey': '#808080',
      'green': '#008000',
      'greenyellow': '#adff2f',
      'honeydew': '#f0fff0',
      'hotpink': '#ff69b4',
      'indianred': '#cd5c5c',
      'indigo': '#4b0082',
      'ivory': '#fffff0',
      'khaki': '#f0e68c',
      'lavender': '#e6e6fa',
      'lavenderblush': '#fff0f5',
      'lawngreen': '#7cfc00',
      'lemonchiffon': '#fffacd',
      'lightblue': '#add8e6',
      'lightcoral': '#f08080',
      'lightcyan': '#e0ffff',
      'lightgoldenrodyellow': '#fafad2',
      'lightgray': '#d3d3d3',
      'lightgrey': '#d3d3d3',
      'lightgreen': '#90ee90',
      'lightpink': '#ffb6c1',
      'lightsalmon': '#ffa07a',
      'lightseagreen': '#20b2aa',
      'lightskyblue': '#87cefa',
      'lightslategray': '#778899',
      'lightslategrey': '#778899',
      'lightsteelblue': '#b0c4de',
      'lightyellow': '#ffffe0',
      'lime': '#00ff00',
      'limegreen': '#32cd32',
      'linen': '#faf0e6',
      'magenta': '#ff00ff',
      'maroon': '#800000',
      'mediumaquamarine': '#66cdaa',
      'mediumblue': '#0000cd',
      'mediumorchid': '#ba55d3',
      'mediumpurple': '#9370d8',
      'mediumseagreen': '#3cb371',
      'mediumslateblue': '#7b68ee',
      'mediumspringgreen': '#00fa9a',
      'mediumturquoise': '#48d1cc',
      'mediumvioletred': '#c71585',
      'midnightblue': '#191970',
      'mintcream': '#f5fffa',
      'mistyrose': '#ffe4e1',
      'moccasin': '#ffe4b5',
      'navajowhite': '#ffdead',
      'navy': '#000080',
      'oldlace': '#fdf5e6',
      'olive': '#808000',
      'olivedrab': '#6b8e23',
      'orange': '#ffa500',
      'orangered': '#ff4500',
      'orchid': '#da70d6',
      'palegoldenrod': '#eee8aa',
      'palegreen': '#98fb98',
      'paleturquoise': '#afeeee',
      'palevioletred': '#d87093',
      'papayawhip': '#ffefd5',
      'peachpuff': '#ffdab9',
      'peru': '#cd853f',
      'pink': '#ffc0cb',
      'plum': '#dda0dd',
      'powderblue': '#b0e0e6',
      'purple': '#800080',
      'rebeccapurple': '#663399',
      'red': '#ff0000',
      'rosybrown': '#bc8f8f',
      'royalblue': '#4169e1',
      'saddlebrown': '#8b4513',
      'salmon': '#fa8072',
      'sandybrown': '#f4a460',
      'seagreen': '#2e8b57',
      'seashell': '#fff5ee',
      'sienna': '#a0522d',
      'silver': '#c0c0c0',
      'skyblue': '#87ceeb',
      'slateblue': '#6a5acd',
      'slategray': '#708090',
      'slategrey': '#708090',
      'snow': '#fffafa',
      'springgreen': '#00ff7f',
      'steelblue': '#4682b4',
      'tan': '#d2b48c',
      'teal': '#008080',
      'thistle': '#d8bfd8',
      'tomato': '#ff6347',
      'turquoise': '#40e0d0',
      'violet': '#ee82ee',
      'wheat': '#f5deb3',
      'white': '#ffffff',
      'whitesmoke': '#f5f5f5',
      'yellow': '#ffff00',
      'yellowgreen': '#9acd32'
  };

  var unitConversions = {
      length: {
          'm': 1,
          'cm': 0.01,
          'mm': 0.001,
          'in': 0.0254,
          'px': 0.0254 / 96,
          'pt': 0.0254 / 72,
          'pc': 0.0254 / 72 * 12
      },
      duration: {
          's': 1,
          'ms': 0.001
      },
      angle: {
          'rad': 1 / (2 * Math.PI),
          'deg': 1 / 360,
          'grad': 1 / 400,
          'turn': 1
      }
  };

  var data = { colors: colors, unitConversions: unitConversions };

  var Node = /** @class */ (function () {
      function Node() {
          this.parent = null;
          this.visibilityBlocks = undefined;
          this.nodeVisible = undefined;
          this.rootNode = null;
          this.parsed = null;
          var self = this;
          Object.defineProperty(this, 'currentFileInfo', {
              get: function () { return self.fileInfo(); }
          });
          Object.defineProperty(this, 'index', {
              get: function () { return self.getIndex(); }
          });
      }
      Node.prototype.setParent = function (nodes, parent) {
          function set(node) {
              if (node && node instanceof Node) {
                  node.parent = parent;
              }
          }
          if (Array.isArray(nodes)) {
              nodes.forEach(set);
          }
          else {
              set(nodes);
          }
      };
      Node.prototype.getIndex = function () {
          return this._index || (this.parent && this.parent.getIndex()) || 0;
      };
      Node.prototype.fileInfo = function () {
          return this._fileInfo || (this.parent && this.parent.fileInfo()) || {};
      };
      Node.prototype.isRulesetLike = function () {
          return false;
      };
      Node.prototype.toCSS = function (context) {
          var strs = [];
          this.genCSS(context, {
              add: function (chunk, fileInfo, index) {
                  strs.push(chunk);
              },
              isEmpty: function () {
                  return strs.length === 0;
              }
          });
          return strs.join('');
      };
      Node.prototype.genCSS = function (context, output) {
          output.add(this.value);
      };
      Node.prototype.accept = function (visitor) {
          this.value = visitor.visit(this.value);
      };
      Node.prototype.eval = function () { return this; };
      Node.prototype._operate = function (context, op, a, b) {
          switch (op) {
              case '+': return a + b;
              case '-': return a - b;
              case '*': return a * b;
              case '/': return a / b;
          }
      };
      Node.prototype.fround = function (context, value) {
          var precision = context && context.numPrecision;
          // add "epsilon" to ensure numbers like 1.000000005 (represented as 1.000000004999...) are properly rounded:
          return (precision) ? Number((value + 2e-16).toFixed(precision)) : value;
      };
      // Returns true if this node represents root of ast imported by reference
      Node.prototype.blocksVisibility = function () {
          if (this.visibilityBlocks == null) {
              this.visibilityBlocks = 0;
          }
          return this.visibilityBlocks !== 0;
      };
      Node.prototype.addVisibilityBlock = function () {
          if (this.visibilityBlocks == null) {
              this.visibilityBlocks = 0;
          }
          this.visibilityBlocks = this.visibilityBlocks + 1;
      };
      Node.prototype.removeVisibilityBlock = function () {
          if (this.visibilityBlocks == null) {
              this.visibilityBlocks = 0;
          }
          this.visibilityBlocks = this.visibilityBlocks - 1;
      };
      // Turns on node visibility - if called node will be shown in output regardless
      // of whether it comes from import by reference or not
      Node.prototype.ensureVisibility = function () {
          this.nodeVisible = true;
      };
      // Turns off node visibility - if called node will NOT be shown in output regardless
      // of whether it comes from import by reference or not
      Node.prototype.ensureInvisibility = function () {
          this.nodeVisible = false;
      };
      // return values:
      // false - the node must not be visible
      // true - the node must be visible
      // undefined or null - the node has the same visibility as its parent
      Node.prototype.isVisible = function () {
          return this.nodeVisible;
      };
      Node.prototype.visibilityInfo = function () {
          return {
              visibilityBlocks: this.visibilityBlocks,
              nodeVisible: this.nodeVisible
          };
      };
      Node.prototype.copyVisibilityInfo = function (info) {
          if (!info) {
              return;
          }
          this.visibilityBlocks = info.visibilityBlocks;
          this.nodeVisible = info.nodeVisible;
      };
      return Node;
  }());
  Node.compare = function (a, b) {
      /* returns:
       -1: a < b
       0: a = b
       1: a > b
       and *any* other value for a != b (e.g. undefined, NaN, -2 etc.) */
      if ((a.compare) &&
          // for "symmetric results" force toCSS-based comparison
          // of Quoted or Anonymous if either value is one of those
          !(b.type === 'Quoted' || b.type === 'Anonymous')) {
          return a.compare(b);
      }
      else if (b.compare) {
          return -b.compare(a);
      }
      else if (a.type !== b.type) {
          return undefined;
      }
      a = a.value;
      b = b.value;
      if (!Array.isArray(a)) {
          return a === b ? 0 : undefined;
      }
      if (a.length !== b.length) {
          return undefined;
      }
      for (var i_1 = 0; i_1 < a.length; i_1++) {
          if (Node.compare(a[i_1], b[i_1]) !== 0) {
              return undefined;
          }
      }
      return 0;
  };
  Node.numericCompare = function (a, b) { return a < b ? -1
      : a === b ? 0
          : a > b ? 1 : undefined; };

  //
  // RGB Colors - #ff0014, #eee
  //
  var Color = /** @class */ (function (_super) {
      __extends(Color, _super);
      function Color(rgb, a, originalForm) {
          var _this = _super.call(this) || this;
          var self = _this;
          //
          // The end goal here, is to parse the arguments
          // into an integer triplet, such as `128, 255, 0`
          //
          // This facilitates operations and conversions.
          //
          if (Array.isArray(rgb)) {
              _this.rgb = rgb;
          }
          else if (rgb.length >= 6) {
              _this.rgb = [];
              rgb.match(/.{2}/g).map(function (c, i) {
                  if (i < 3) {
                      self.rgb.push(parseInt(c, 16));
                  }
                  else {
                      self.alpha = (parseInt(c, 16)) / 255;
                  }
              });
          }
          else {
              _this.rgb = [];
              rgb.split('').map(function (c, i) {
                  if (i < 3) {
                      self.rgb.push(parseInt(c + c, 16));
                  }
                  else {
                      self.alpha = (parseInt(c + c, 16)) / 255;
                  }
              });
          }
          _this.alpha = _this.alpha || (typeof a === 'number' ? a : 1);
          if (typeof originalForm !== 'undefined') {
              _this.value = originalForm;
          }
          return _this;
      }
      Color.prototype.luma = function () {
          var r = this.rgb[0] / 255;
          var g = this.rgb[1] / 255;
          var b = this.rgb[2] / 255;
          r = (r <= 0.03928) ? r / 12.92 : Math.pow(((r + 0.055) / 1.055), 2.4);
          g = (g <= 0.03928) ? g / 12.92 : Math.pow(((g + 0.055) / 1.055), 2.4);
          b = (b <= 0.03928) ? b / 12.92 : Math.pow(((b + 0.055) / 1.055), 2.4);
          return 0.2126 * r + 0.7152 * g + 0.0722 * b;
      };
      Color.prototype.genCSS = function (context, output) {
          output.add(this.toCSS(context));
      };
      Color.prototype.toCSS = function (context, doNotCompress) {
          var compress = context && context.compress && !doNotCompress;
          var color;
          var alpha;
          var colorFunction;
          var args = [];
          // `value` is set if this color was originally
          // converted from a named color string so we need
          // to respect this and try to output named color too.
          alpha = this.fround(context, this.alpha);
          if (this.value) {
              if (this.value.indexOf('rgb') === 0) {
                  if (alpha < 1) {
                      colorFunction = 'rgba';
                  }
              }
              else if (this.value.indexOf('hsl') === 0) {
                  if (alpha < 1) {
                      colorFunction = 'hsla';
                  }
                  else {
                      colorFunction = 'hsl';
                  }
              }
              else {
                  return this.value;
              }
          }
          else {
              if (alpha < 1) {
                  colorFunction = 'rgba';
              }
          }
          switch (colorFunction) {
              case 'rgba':
                  args = this.rgb.map(function (c) { return clamp(Math.round(c), 255); }).concat(clamp(alpha, 1));
                  break;
              case 'hsla':
                  args.push(clamp(alpha, 1));
              case 'hsl':
                  color = this.toHSL();
                  args = [
                      this.fround(context, color.h),
                      this.fround(context, color.s * 100) + "%",
                      this.fround(context, color.l * 100) + "%"
                  ].concat(args);
          }
          if (colorFunction) {
              // Values are capped between `0` and `255`, rounded and zero-padded.
              return colorFunction + "(" + args.join("," + (compress ? '' : ' ')) + ")";
          }
          color = this.toRGB();
          if (compress) {
              var splitcolor = color.split('');
              // Convert color to short format
              if (splitcolor[1] === splitcolor[2] && splitcolor[3] === splitcolor[4] && splitcolor[5] === splitcolor[6]) {
                  color = "#" + splitcolor[1] + splitcolor[3] + splitcolor[5];
              }
          }
          return color;
      };
      //
      // Operations have to be done per-channel, if not,
      // channels will spill onto each other. Once we have
      // our result, in the form of an integer triplet,
      // we create a new Color node to hold the result.
      //
      Color.prototype.operate = function (context, op, other) {
          var rgb = new Array(3);
          var alpha = this.alpha * (1 - other.alpha) + other.alpha;
          for (var c = 0; c < 3; c++) {
              rgb[c] = this._operate(context, op, this.rgb[c], other.rgb[c]);
          }
          return new Color(rgb, alpha);
      };
      Color.prototype.toRGB = function () {
          return toHex(this.rgb);
      };
      Color.prototype.toHSL = function () {
          var r = this.rgb[0] / 255;
          var g = this.rgb[1] / 255;
          var b = this.rgb[2] / 255;
          var a = this.alpha;
          var max = Math.max(r, g, b);
          var min = Math.min(r, g, b);
          var h;
          var s;
          var l = (max + min) / 2;
          var d = max - min;
          if (max === min) {
              h = s = 0;
          }
          else {
              s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
              switch (max) {
                  case r:
                      h = (g - b) / d + (g < b ? 6 : 0);
                      break;
                  case g:
                      h = (b - r) / d + 2;
                      break;
                  case b:
                      h = (r - g) / d + 4;
                      break;
              }
              h /= 6;
          }
          return { h: h * 360, s: s, l: l, a: a };
      };
      // Adapted from http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
      Color.prototype.toHSV = function () {
          var r = this.rgb[0] / 255;
          var g = this.rgb[1] / 255;
          var b = this.rgb[2] / 255;
          var a = this.alpha;
          var max = Math.max(r, g, b);
          var min = Math.min(r, g, b);
          var h;
          var s;
          var v = max;
          var d = max - min;
          if (max === 0) {
              s = 0;
          }
          else {
              s = d / max;
          }
          if (max === min) {
              h = 0;
          }
          else {
              switch (max) {
                  case r:
                      h = (g - b) / d + (g < b ? 6 : 0);
                      break;
                  case g:
                      h = (b - r) / d + 2;
                      break;
                  case b:
                      h = (r - g) / d + 4;
                      break;
              }
              h /= 6;
          }
          return { h: h * 360, s: s, v: v, a: a };
      };
      Color.prototype.toARGB = function () {
          return toHex([this.alpha * 255].concat(this.rgb));
      };
      Color.prototype.compare = function (x) {
          return (x.rgb &&
              x.rgb[0] === this.rgb[0] &&
              x.rgb[1] === this.rgb[1] &&
              x.rgb[2] === this.rgb[2] &&
              x.alpha === this.alpha) ? 0 : undefined;
      };
      return Color;
  }(Node));
  Color.prototype.type = 'Color';
  function clamp(v, max) {
      return Math.min(Math.max(v, 0), max);
  }
  function toHex(v) {
      return "#" + v.map(function (c) {
          c = clamp(Math.round(c), 255);
          return (c < 16 ? '0' : '') + c.toString(16);
      }).join('');
  }
  Color.fromKeyword = function (keyword) {
      var c;
      var key = keyword.toLowerCase();
      if (colors.hasOwnProperty(key)) {
          c = new Color(colors[key].slice(1));
      }
      else if (key === 'transparent') {
          c = new Color([0, 0, 0], 0);
      }
      if (c) {
          c.value = keyword;
          return c;
      }
  };

  var Paren = /** @class */ (function (_super) {
      __extends(Paren, _super);
      function Paren(node) {
          var _this = _super.call(this) || this;
          _this.value = node;
          return _this;
      }
      Paren.prototype.genCSS = function (context, output) {
          output.add('(');
          this.value.genCSS(context, output);
          output.add(')');
      };
      Paren.prototype.eval = function (context) {
          return new Paren(this.value.eval(context));
      };
      return Paren;
  }(Node));
  Paren.prototype.type = 'Paren';

  var _noSpaceCombinators = {
      '': true,
      ' ': true,
      '|': true
  };
  var Combinator = /** @class */ (function (_super) {
      __extends(Combinator, _super);
      function Combinator(value) {
          var _this = _super.call(this) || this;
          if (value === ' ') {
              _this.value = ' ';
              _this.emptyOrWhitespace = true;
          }
          else {
              _this.value = value ? value.trim() : '';
              _this.emptyOrWhitespace = _this.value === '';
          }
          return _this;
      }
      Combinator.prototype.genCSS = function (context, output) {
          var spaceOrEmpty = (context.compress || _noSpaceCombinators[this.value]) ? '' : ' ';
          output.add(spaceOrEmpty + this.value + spaceOrEmpty);
      };
      return Combinator;
  }(Node));
  Combinator.prototype.type = 'Combinator';

  var Element = /** @class */ (function (_super) {
      __extends(Element, _super);
      function Element(combinator, value, isVariable, index, currentFileInfo, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this.combinator = combinator instanceof Combinator ?
              combinator : new Combinator(combinator);
          if (typeof value === 'string') {
              _this.value = value.trim();
          }
          else if (value) {
              _this.value = value;
          }
          else {
              _this.value = '';
          }
          _this.isVariable = isVariable;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.copyVisibilityInfo(visibilityInfo);
          _this.setParent(_this.combinator, _this);
          return _this;
      }
      Element.prototype.accept = function (visitor) {
          var value = this.value;
          this.combinator = visitor.visit(this.combinator);
          if (typeof value === 'object') {
              this.value = visitor.visit(value);
          }
      };
      Element.prototype.eval = function (context) {
          return new Element(this.combinator, this.value.eval ? this.value.eval(context) : this.value, this.isVariable, this.getIndex(), this.fileInfo(), this.visibilityInfo());
      };
      Element.prototype.clone = function () {
          return new Element(this.combinator, this.value, this.isVariable, this.getIndex(), this.fileInfo(), this.visibilityInfo());
      };
      Element.prototype.genCSS = function (context, output) {
          output.add(this.toCSS(context), this.fileInfo(), this.getIndex());
      };
      Element.prototype.toCSS = function (context) {
          if (context === void 0) { context = {}; }
          var value = this.value;
          var firstSelector = context.firstSelector;
          if (value instanceof Paren) {
              // selector in parens should not be affected by outer selector
              // flags (breaks only interpolated selectors - see #1973)
              context.firstSelector = true;
          }
          value = value.toCSS ? value.toCSS(context) : value;
          context.firstSelector = firstSelector;
          if (value === '' && this.combinator.value.charAt(0) === '&') {
              return '';
          }
          else {
              return this.combinator.toCSS(context) + value;
          }
      };
      return Element;
  }(Node));
  Element.prototype.type = 'Element';

  var Math$1 = {
      ALWAYS: 0,
      PARENS_DIVISION: 1,
      PARENS: 2,
      STRICT_LEGACY: 3
  };
  var RewriteUrls = {
      OFF: 0,
      LOCAL: 1,
      ALL: 2
  };

  function createCommonjsModule(fn, module) {
  	return module = { exports: {} }, fn(module, module.exports), module.exports;
  }

  var clone_1 = createCommonjsModule(function (module) {
      var clone = (function () {
          function _instanceof(obj, type) {
              return type != null && obj instanceof type;
          }
          var nativeMap;
          try {
              nativeMap = Map;
          }
          catch (_) {
              // maybe a reference error because no `Map`. Give it a dummy value that no
              // value will ever be an instanceof.
              nativeMap = function () { };
          }
          var nativeSet;
          try {
              nativeSet = Set;
          }
          catch (_) {
              nativeSet = function () { };
          }
          var nativePromise;
          try {
              nativePromise = Promise;
          }
          catch (_) {
              nativePromise = function () { };
          }
          /**
           * Clones (copies) an Object using deep copying.
           *
           * This function supports circular references by default, but if you are certain
           * there are no circular references in your object, you can save some CPU time
           * by calling clone(obj, false).
           *
           * Caution: if `circular` is false and `parent` contains circular references,
           * your program may enter an infinite loop and crash.
           *
           * @param `parent` - the object to be cloned
           * @param `circular` - set to true if the object to be cloned may contain
           *    circular references. (optional - true by default)
           * @param `depth` - set to a number if the object is only to be cloned to
           *    a particular depth. (optional - defaults to Infinity)
           * @param `prototype` - sets the prototype to be used when cloning an object.
           *    (optional - defaults to parent prototype).
           * @param `includeNonEnumerable` - set to true if the non-enumerable properties
           *    should be cloned as well. Non-enumerable properties on the prototype
           *    chain will be ignored. (optional - false by default)
          */
          function clone(parent, circular, depth, prototype, includeNonEnumerable) {
              if (typeof circular === 'object') {
                  depth = circular.depth;
                  prototype = circular.prototype;
                  includeNonEnumerable = circular.includeNonEnumerable;
                  circular = circular.circular;
              }
              // maintain two arrays for circular references, where corresponding parents
              // and children have the same index
              var allParents = [];
              var allChildren = [];
              var useBuffer = typeof Buffer != 'undefined';
              if (typeof circular == 'undefined')
                  circular = true;
              if (typeof depth == 'undefined')
                  depth = Infinity;
              // recurse this function so we don't reset allParents and allChildren
              function _clone(parent, depth) {
                  // cloning null always returns null
                  if (parent === null)
                      return null;
                  if (depth === 0)
                      return parent;
                  var child;
                  var proto;
                  if (typeof parent != 'object') {
                      return parent;
                  }
                  if (_instanceof(parent, nativeMap)) {
                      child = new nativeMap();
                  }
                  else if (_instanceof(parent, nativeSet)) {
                      child = new nativeSet();
                  }
                  else if (_instanceof(parent, nativePromise)) {
                      child = new nativePromise(function (resolve, reject) {
                          parent.then(function (value) {
                              resolve(_clone(value, depth - 1));
                          }, function (err) {
                              reject(_clone(err, depth - 1));
                          });
                      });
                  }
                  else if (clone.__isArray(parent)) {
                      child = [];
                  }
                  else if (clone.__isRegExp(parent)) {
                      child = new RegExp(parent.source, __getRegExpFlags(parent));
                      if (parent.lastIndex)
                          child.lastIndex = parent.lastIndex;
                  }
                  else if (clone.__isDate(parent)) {
                      child = new Date(parent.getTime());
                  }
                  else if (useBuffer && Buffer.isBuffer(parent)) {
                      if (Buffer.allocUnsafe) {
                          // Node.js >= 4.5.0
                          child = Buffer.allocUnsafe(parent.length);
                      }
                      else {
                          // Older Node.js versions
                          child = new Buffer(parent.length);
                      }
                      parent.copy(child);
                      return child;
                  }
                  else if (_instanceof(parent, Error)) {
                      child = Object.create(parent);
                  }
                  else {
                      if (typeof prototype == 'undefined') {
                          proto = Object.getPrototypeOf(parent);
                          child = Object.create(proto);
                      }
                      else {
                          child = Object.create(prototype);
                          proto = prototype;
                      }
                  }
                  if (circular) {
                      var index = allParents.indexOf(parent);
                      if (index != -1) {
                          return allChildren[index];
                      }
                      allParents.push(parent);
                      allChildren.push(child);
                  }
                  if (_instanceof(parent, nativeMap)) {
                      parent.forEach(function (value, key) {
                          var keyChild = _clone(key, depth - 1);
                          var valueChild = _clone(value, depth - 1);
                          child.set(keyChild, valueChild);
                      });
                  }
                  if (_instanceof(parent, nativeSet)) {
                      parent.forEach(function (value) {
                          var entryChild = _clone(value, depth - 1);
                          child.add(entryChild);
                      });
                  }
                  for (var i in parent) {
                      var attrs;
                      if (proto) {
                          attrs = Object.getOwnPropertyDescriptor(proto, i);
                      }
                      if (attrs && attrs.set == null) {
                          continue;
                      }
                      child[i] = _clone(parent[i], depth - 1);
                  }
                  if (Object.getOwnPropertySymbols) {
                      var symbols = Object.getOwnPropertySymbols(parent);
                      for (var i = 0; i < symbols.length; i++) {
                          // Don't need to worry about cloning a symbol because it is a primitive,
                          // like a number or string.
                          var symbol = symbols[i];
                          var descriptor = Object.getOwnPropertyDescriptor(parent, symbol);
                          if (descriptor && !descriptor.enumerable && !includeNonEnumerable) {
                              continue;
                          }
                          child[symbol] = _clone(parent[symbol], depth - 1);
                          if (!descriptor.enumerable) {
                              Object.defineProperty(child, symbol, {
                                  enumerable: false
                              });
                          }
                      }
                  }
                  if (includeNonEnumerable) {
                      var allPropertyNames = Object.getOwnPropertyNames(parent);
                      for (var i = 0; i < allPropertyNames.length; i++) {
                          var propertyName = allPropertyNames[i];
                          var descriptor = Object.getOwnPropertyDescriptor(parent, propertyName);
                          if (descriptor && descriptor.enumerable) {
                              continue;
                          }
                          child[propertyName] = _clone(parent[propertyName], depth - 1);
                          Object.defineProperty(child, propertyName, {
                              enumerable: false
                          });
                      }
                  }
                  return child;
              }
              return _clone(parent, depth);
          }
          /**
           * Simple flat clone using prototype, accepts only objects, usefull for property
           * override on FLAT configuration object (no nested props).
           *
           * USE WITH CAUTION! This may not behave as you wish if you do not know how this
           * works.
           */
          clone.clonePrototype = function clonePrototype(parent) {
              if (parent === null)
                  return null;
              var c = function () { };
              c.prototype = parent;
              return new c();
          };
          // private utility functions
          function __objToStr(o) {
              return Object.prototype.toString.call(o);
          }
          clone.__objToStr = __objToStr;
          function __isDate(o) {
              return typeof o === 'object' && __objToStr(o) === '[object Date]';
          }
          clone.__isDate = __isDate;
          function __isArray(o) {
              return typeof o === 'object' && __objToStr(o) === '[object Array]';
          }
          clone.__isArray = __isArray;
          function __isRegExp(o) {
              return typeof o === 'object' && __objToStr(o) === '[object RegExp]';
          }
          clone.__isRegExp = __isRegExp;
          function __getRegExpFlags(re) {
              var flags = '';
              if (re.global)
                  flags += 'g';
              if (re.ignoreCase)
                  flags += 'i';
              if (re.multiline)
                  flags += 'm';
              return flags;
          }
          clone.__getRegExpFlags = __getRegExpFlags;
          return clone;
      })();
      if ( module.exports) {
          module.exports = clone;
      }
  });

  /* jshint proto: true */
  function getLocation(index, inputStream) {
      var n = index + 1;
      var line = null;
      var column = -1;
      while (--n >= 0 && inputStream.charAt(n) !== '\n') {
          column++;
      }
      if (typeof index === 'number') {
          line = (inputStream.slice(0, index).match(/\n/g) || '').length;
      }
      return {
          line: line,
          column: column
      };
  }
  function copyArray(arr) {
      var i;
      var length = arr.length;
      var copy = new Array(length);
      for (i = 0; i < length; i++) {
          copy[i] = arr[i];
      }
      return copy;
  }
  function clone(obj) {
      var cloned = {};
      for (var prop in obj) {
          if (obj.hasOwnProperty(prop)) {
              cloned[prop] = obj[prop];
          }
      }
      return cloned;
  }
  function defaults(obj1, obj2) {
      var newObj = obj2 || {};
      if (!obj2._defaults) {
          newObj = {};
          var defaults_1 = clone_1(obj1);
          newObj._defaults = defaults_1;
          var cloned = obj2 ? clone_1(obj2) : {};
          Object.assign(newObj, defaults_1, cloned);
      }
      return newObj;
  }
  function copyOptions(obj1, obj2) {
      if (obj2 && obj2._defaults) {
          return obj2;
      }
      var opts = defaults(obj1, obj2);
      if (opts.strictMath) {
          opts.math = Math$1.STRICT_LEGACY;
      }
      // Back compat with changed relativeUrls option
      if (opts.relativeUrls) {
          opts.rewriteUrls = RewriteUrls.ALL;
      }
      if (typeof opts.math === 'string') {
          switch (opts.math.toLowerCase()) {
              case 'always':
                  opts.math = Math$1.ALWAYS;
                  break;
              case 'parens-division':
                  opts.math = Math$1.PARENS_DIVISION;
                  break;
              case 'strict':
              case 'parens':
                  opts.math = Math$1.PARENS;
                  break;
              case 'strict-legacy':
                  opts.math = Math$1.STRICT_LEGACY;
          }
      }
      if (typeof opts.rewriteUrls === 'string') {
          switch (opts.rewriteUrls.toLowerCase()) {
              case 'off':
                  opts.rewriteUrls = RewriteUrls.OFF;
                  break;
              case 'local':
                  opts.rewriteUrls = RewriteUrls.LOCAL;
                  break;
              case 'all':
                  opts.rewriteUrls = RewriteUrls.ALL;
                  break;
          }
      }
      return opts;
  }
  function merge(obj1, obj2) {
      for (var prop in obj2) {
          if (obj2.hasOwnProperty(prop)) {
              obj1[prop] = obj2[prop];
          }
      }
      return obj1;
  }
  function flattenArray(arr, result) {
      if (result === void 0) { result = []; }
      for (var i_1 = 0, length_1 = arr.length; i_1 < length_1; i_1++) {
          var value = arr[i_1];
          if (Array.isArray(value)) {
              flattenArray(value, result);
          }
          else {
              if (value !== undefined) {
                  result.push(value);
              }
          }
      }
      return result;
  }

  var utils = /*#__PURE__*/Object.freeze({
    __proto__: null,
    getLocation: getLocation,
    copyArray: copyArray,
    clone: clone,
    defaults: defaults,
    copyOptions: copyOptions,
    merge: merge,
    flattenArray: flattenArray
  });

  var anonymousFunc = /(<anonymous>|Function):(\d+):(\d+)/;
  /**
   * This is a centralized class of any error that could be thrown internally (mostly by the parser).
   * Besides standard .message it keeps some additional data like a path to the file where the error
   * occurred along with line and column numbers.
   *
   * @class
   * @extends Error
   * @type {module.LessError}
   *
   * @prop {string} type
   * @prop {string} filename
   * @prop {number} index
   * @prop {number} line
   * @prop {number} column
   * @prop {number} callLine
   * @prop {number} callExtract
   * @prop {string[]} extract
   *
   * @param {Object} e              - An error object to wrap around or just a descriptive object
   * @param {Object} fileContentMap - An object with file contents in 'contents' property (like importManager) @todo - move to fileManager?
   * @param {string} [currentFilename]
   */
  var LessError = function LessError(e, fileContentMap, currentFilename) {
      Error.call(this);
      var filename = e.filename || currentFilename;
      this.message = e.message;
      this.stack = e.stack;
      if (fileContentMap && filename) {
          var input = fileContentMap.contents[filename];
          var loc = getLocation(e.index, input);
          var line = loc.line;
          var col = loc.column;
          var callLine = e.call && getLocation(e.call, input).line;
          var lines = input ? input.split('\n') : '';
          this.type = e.type || 'Syntax';
          this.filename = filename;
          this.index = e.index;
          this.line = typeof line === 'number' ? line + 1 : null;
          this.column = col;
          if (!this.line && this.stack) {
              var found = this.stack.match(anonymousFunc);
              /**
               * We have to figure out how this environment stringifies anonymous functions
               * so we can correctly map plugin errors.
               *
               * Note, in Node 8, the output of anonymous funcs varied based on parameters
               * being present or not, so we inject dummy params.
               */
              var func = new Function('a', 'throw new Error()');
              var lineAdjust = 0;
              try {
                  func();
              }
              catch (e) {
                  var match = e.stack.match(anonymousFunc);
                  var line_1 = parseInt(match[2]);
                  lineAdjust = 1 - line_1;
              }
              if (found) {
                  if (found[2]) {
                      this.line = parseInt(found[2]) + lineAdjust;
                  }
                  if (found[3]) {
                      this.column = parseInt(found[3]);
                  }
              }
          }
          this.callLine = callLine + 1;
          this.callExtract = lines[callLine];
          this.extract = [
              lines[this.line - 2],
              lines[this.line - 1],
              lines[this.line]
          ];
      }
  };
  if (typeof Object.create === 'undefined') {
      var F = function () { };
      F.prototype = Error.prototype;
      LessError.prototype = new F();
  }
  else {
      LessError.prototype = Object.create(Error.prototype);
  }
  LessError.prototype.constructor = LessError;
  /**
   * An overridden version of the default Object.prototype.toString
   * which uses additional information to create a helpful message.
   *
   * @param {Object} options
   * @returns {string}
   */
  LessError.prototype.toString = function (options) {
      if (options === void 0) { options = {}; }
      var message = '';
      var extract = this.extract || [];
      var error = [];
      var stylize = function (str) { return str; };
      if (options.stylize) {
          var type = typeof options.stylize;
          if (type !== 'function') {
              throw Error("options.stylize should be a function, got a " + type + "!");
          }
          stylize = options.stylize;
      }
      if (this.line !== null) {
          if (typeof extract[0] === 'string') {
              error.push(stylize(this.line - 1 + " " + extract[0], 'grey'));
          }
          if (typeof extract[1] === 'string') {
              var errorTxt = this.line + " ";
              if (extract[1]) {
                  errorTxt += extract[1].slice(0, this.column) +
                      stylize(stylize(stylize(extract[1].substr(this.column, 1), 'bold') +
                          extract[1].slice(this.column + 1), 'red'), 'inverse');
              }
              error.push(errorTxt);
          }
          if (typeof extract[2] === 'string') {
              error.push(stylize(this.line + 1 + " " + extract[2], 'grey'));
          }
          error = error.join('\n') + stylize('', 'reset') + "\n";
      }
      message += stylize(this.type + "Error: " + this.message, 'red');
      if (this.filename) {
          message += stylize(' in ', 'red') + this.filename;
      }
      if (this.line) {
          message += stylize(" on line " + this.line + ", column " + (this.column + 1) + ":", 'grey');
      }
      message += "\n" + error;
      if (this.callLine) {
          message += stylize('from ', 'red') + (this.filename || '') + "/n";
          message += stylize(this.callLine, 'grey') + " " + this.callExtract + "/n";
      }
      return message;
  };

  var Selector = /** @class */ (function (_super) {
      __extends(Selector, _super);
      function Selector(elements, extendList, condition, index, currentFileInfo, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this.extendList = extendList;
          _this.condition = condition;
          _this.evaldCondition = !condition;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.elements = _this.getElements(elements);
          _this.mixinElements_ = undefined;
          _this.copyVisibilityInfo(visibilityInfo);
          _this.setParent(_this.elements, _this);
          return _this;
      }
      Selector.prototype.accept = function (visitor) {
          if (this.elements) {
              this.elements = visitor.visitArray(this.elements);
          }
          if (this.extendList) {
              this.extendList = visitor.visitArray(this.extendList);
          }
          if (this.condition) {
              this.condition = visitor.visit(this.condition);
          }
      };
      Selector.prototype.createDerived = function (elements, extendList, evaldCondition) {
          elements = this.getElements(elements);
          var newSelector = new Selector(elements, extendList || this.extendList, null, this.getIndex(), this.fileInfo(), this.visibilityInfo());
          newSelector.evaldCondition = (evaldCondition != null) ? evaldCondition : this.evaldCondition;
          newSelector.mediaEmpty = this.mediaEmpty;
          return newSelector;
      };
      Selector.prototype.getElements = function (els) {
          if (!els) {
              return [new Element('', '&', false, this._index, this._fileInfo)];
          }
          if (typeof els === 'string') {
              this.parse.parseNode(els, ['selector'], this._index, this._fileInfo, function (err, result) {
                  if (err) {
                      throw new LessError({
                          index: err.index,
                          message: err.message
                      }, this.parse.imports, this._fileInfo.filename);
                  }
                  els = result[0].elements;
              });
          }
          return els;
      };
      Selector.prototype.createEmptySelectors = function () {
          var el = new Element('', '&', false, this._index, this._fileInfo);
          var sels = [new Selector([el], null, null, this._index, this._fileInfo)];
          sels[0].mediaEmpty = true;
          return sels;
      };
      Selector.prototype.match = function (other) {
          var elements = this.elements;
          var len = elements.length;
          var olen;
          var i;
          other = other.mixinElements();
          olen = other.length;
          if (olen === 0 || len < olen) {
              return 0;
          }
          else {
              for (i = 0; i < olen; i++) {
                  if (elements[i].value !== other[i]) {
                      return 0;
                  }
              }
          }
          return olen; // return number of matched elements
      };
      Selector.prototype.mixinElements = function () {
          if (this.mixinElements_) {
              return this.mixinElements_;
          }
          var elements = this.elements.map(function (v) { return v.combinator.value + (v.value.value || v.value); }).join('').match(/[,&#\*\.\w-]([\w-]|(\\.))*/g);
          if (elements) {
              if (elements[0] === '&') {
                  elements.shift();
              }
          }
          else {
              elements = [];
          }
          return (this.mixinElements_ = elements);
      };
      Selector.prototype.isJustParentSelector = function () {
          return !this.mediaEmpty &&
              this.elements.length === 1 &&
              this.elements[0].value === '&' &&
              (this.elements[0].combinator.value === ' ' || this.elements[0].combinator.value === '');
      };
      Selector.prototype.eval = function (context) {
          var evaldCondition = this.condition && this.condition.eval(context);
          var elements = this.elements;
          var extendList = this.extendList;
          elements = elements && elements.map(function (e) { return e.eval(context); });
          extendList = extendList && extendList.map(function (extend) { return extend.eval(context); });
          return this.createDerived(elements, extendList, evaldCondition);
      };
      Selector.prototype.genCSS = function (context, output) {
          var i;
          var element;
          if ((!context || !context.firstSelector) && this.elements[0].combinator.value === '') {
              output.add(' ', this.fileInfo(), this.getIndex());
          }
          for (i = 0; i < this.elements.length; i++) {
              element = this.elements[i];
              element.genCSS(context, output);
          }
      };
      Selector.prototype.getIsOutput = function () {
          return this.evaldCondition;
      };
      return Selector;
  }(Node));
  Selector.prototype.type = 'Selector';

  var Value = /** @class */ (function (_super) {
      __extends(Value, _super);
      function Value(value) {
          var _this = _super.call(this) || this;
          if (!value) {
              throw new Error('Value requires an array argument');
          }
          if (!Array.isArray(value)) {
              _this.value = [value];
          }
          else {
              _this.value = value;
          }
          return _this;
      }
      Value.prototype.accept = function (visitor) {
          if (this.value) {
              this.value = visitor.visitArray(this.value);
          }
      };
      Value.prototype.eval = function (context) {
          if (this.value.length === 1) {
              return this.value[0].eval(context);
          }
          else {
              return new Value(this.value.map(function (v) { return v.eval(context); }));
          }
      };
      Value.prototype.genCSS = function (context, output) {
          var i;
          for (i = 0; i < this.value.length; i++) {
              this.value[i].genCSS(context, output);
              if (i + 1 < this.value.length) {
                  output.add((context && context.compress) ? ',' : ', ');
              }
          }
      };
      return Value;
  }(Node));
  Value.prototype.type = 'Value';

  var Keyword = /** @class */ (function (_super) {
      __extends(Keyword, _super);
      function Keyword(value) {
          var _this = _super.call(this) || this;
          _this.value = value;
          return _this;
      }
      Keyword.prototype.genCSS = function (context, output) {
          if (this.value === '%') {
              throw { type: 'Syntax', message: 'Invalid % without number' };
          }
          output.add(this.value);
      };
      return Keyword;
  }(Node));
  Keyword.prototype.type = 'Keyword';
  Keyword.True = new Keyword('true');
  Keyword.False = new Keyword('false');

  var Anonymous = /** @class */ (function (_super) {
      __extends(Anonymous, _super);
      function Anonymous(value, index, currentFileInfo, mapLines, rulesetLike, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this.value = value;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.mapLines = mapLines;
          _this.rulesetLike = (typeof rulesetLike === 'undefined') ? false : rulesetLike;
          _this.allowRoot = true;
          _this.copyVisibilityInfo(visibilityInfo);
          return _this;
      }
      Anonymous.prototype.eval = function () {
          return new Anonymous(this.value, this._index, this._fileInfo, this.mapLines, this.rulesetLike, this.visibilityInfo());
      };
      Anonymous.prototype.compare = function (other) {
          return other.toCSS && this.toCSS() === other.toCSS() ? 0 : undefined;
      };
      Anonymous.prototype.isRulesetLike = function () {
          return this.rulesetLike;
      };
      Anonymous.prototype.genCSS = function (context, output) {
          this.nodeVisible = Boolean(this.value);
          if (this.nodeVisible) {
              output.add(this.value, this._fileInfo, this._index, this.mapLines);
          }
      };
      return Anonymous;
  }(Node));
  Anonymous.prototype.type = 'Anonymous';

  var MATH = Math$1;
  var Declaration = /** @class */ (function (_super) {
      __extends(Declaration, _super);
      function Declaration(name, value, important, merge, index, currentFileInfo, inline, variable) {
          var _this = _super.call(this) || this;
          _this.name = name;
          _this.value = (value instanceof Node) ? value : new Value([value ? new Anonymous(value) : null]);
          _this.important = important ? " " + important.trim() : '';
          _this.merge = merge;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.inline = inline || false;
          _this.variable = (variable !== undefined) ? variable
              : (name.charAt && (name.charAt(0) === '@'));
          _this.allowRoot = true;
          _this.setParent(_this.value, _this);
          return _this;
      }
      Declaration.prototype.genCSS = function (context, output) {
          output.add(this.name + (context.compress ? ':' : ': '), this.fileInfo(), this.getIndex());
          try {
              this.value.genCSS(context, output);
          }
          catch (e) {
              e.index = this._index;
              e.filename = this._fileInfo.filename;
              throw e;
          }
          output.add(this.important + ((this.inline || (context.lastRule && context.compress)) ? '' : ';'), this._fileInfo, this._index);
      };
      Declaration.prototype.eval = function (context) {
          var mathBypass = false;
          var prevMath;
          var name = this.name;
          var evaldValue;
          var variable = this.variable;
          if (typeof name !== 'string') {
              // expand 'primitive' name directly to get
              // things faster (~10% for benchmark.less):
              name = (name.length === 1) && (name[0] instanceof Keyword) ?
                  name[0].value : evalName(context, name);
              variable = false; // never treat expanded interpolation as new variable name
          }
          // @todo remove when parens-division is default
          if (name === 'font' && context.math === MATH.ALWAYS) {
              mathBypass = true;
              prevMath = context.math;
              context.math = MATH.PARENS_DIVISION;
          }
          try {
              context.importantScope.push({});
              evaldValue = this.value.eval(context);
              if (!this.variable && evaldValue.type === 'DetachedRuleset') {
                  throw { message: 'Rulesets cannot be evaluated on a property.',
                      index: this.getIndex(), filename: this.fileInfo().filename };
              }
              var important = this.important;
              var importantResult = context.importantScope.pop();
              if (!important && importantResult.important) {
                  important = importantResult.important;
              }
              return new Declaration(name, evaldValue, important, this.merge, this.getIndex(), this.fileInfo(), this.inline, variable);
          }
          catch (e) {
              if (typeof e.index !== 'number') {
                  e.index = this.getIndex();
                  e.filename = this.fileInfo().filename;
              }
              throw e;
          }
          finally {
              if (mathBypass) {
                  context.math = prevMath;
              }
          }
      };
      Declaration.prototype.makeImportant = function () {
          return new Declaration(this.name, this.value, '!important', this.merge, this.getIndex(), this.fileInfo(), this.inline);
      };
      return Declaration;
  }(Node));
  function evalName(context, name) {
      var value = '';
      var i;
      var n = name.length;
      var output = { add: function (s) { value += s; } };
      for (i = 0; i < n; i++) {
          name[i].eval(context).genCSS(context, output);
      }
      return value;
  }
  Declaration.prototype.type = 'Declaration';

  var debugInfo = function (context, ctx, lineSeparator) {
      var result = '';
      if (context.dumpLineNumbers && !context.compress) {
          switch (context.dumpLineNumbers) {
              case 'comments':
                  result = debugInfo.asComment(ctx);
                  break;
              case 'mediaquery':
                  result = debugInfo.asMediaQuery(ctx);
                  break;
              case 'all':
                  result = debugInfo.asComment(ctx) + (lineSeparator || '') + debugInfo.asMediaQuery(ctx);
                  break;
          }
      }
      return result;
  };
  debugInfo.asComment = function (ctx) { return "/* line " + ctx.debugInfo.lineNumber + ", " + ctx.debugInfo.fileName + " */\n"; };
  debugInfo.asMediaQuery = function (ctx) {
      var filenameWithProtocol = ctx.debugInfo.fileName;
      if (!/^[a-z]+:\/\//i.test(filenameWithProtocol)) {
          filenameWithProtocol = "file://" + filenameWithProtocol;
      }
      return "@media -sass-debug-info{filename{font-family:" + filenameWithProtocol.replace(/([.:\/\\])/g, function (a) {
          if (a == '\\') {
              a = '\/';
          }
          return "\\" + a;
      }) + "}line{font-family:\\00003" + ctx.debugInfo.lineNumber + "}}\n";
  };

  var Comment = /** @class */ (function (_super) {
      __extends(Comment, _super);
      function Comment(value, isLineComment, index, currentFileInfo) {
          var _this = _super.call(this) || this;
          _this.value = value;
          _this.isLineComment = isLineComment;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.allowRoot = true;
          return _this;
      }
      Comment.prototype.genCSS = function (context, output) {
          if (this.debugInfo) {
              output.add(debugInfo(context, this), this.fileInfo(), this.getIndex());
          }
          output.add(this.value);
      };
      Comment.prototype.isSilent = function (context) {
          var isCompressed = context.compress && this.value[2] !== '!';
          return this.isLineComment || isCompressed;
      };
      return Comment;
  }(Node));
  Comment.prototype.type = 'Comment';

  var contexts = {};
  var copyFromOriginal = function copyFromOriginal(original, destination, propertiesToCopy) {
      if (!original) {
          return;
      }
      for (var i_1 = 0; i_1 < propertiesToCopy.length; i_1++) {
          if (original.hasOwnProperty(propertiesToCopy[i_1])) {
              destination[propertiesToCopy[i_1]] = original[propertiesToCopy[i_1]];
          }
      }
  };
  /*
   parse is used whilst parsing
   */
  var parseCopyProperties = [
      // options
      'paths',
      'rewriteUrls',
      'rootpath',
      'strictImports',
      'insecure',
      'dumpLineNumbers',
      'compress',
      'syncImport',
      'chunkInput',
      'mime',
      'useFileCache',
      // context
      'processImports',
      // Used by the import manager to stop multiple import visitors being created.
      'pluginManager' // Used as the plugin manager for the session
  ];
  contexts.Parse = function (options) {
      copyFromOriginal(options, this, parseCopyProperties);
      if (typeof this.paths === 'string') {
          this.paths = [this.paths];
      }
  };
  var evalCopyProperties = [
      'paths',
      'compress',
      'math',
      'strictUnits',
      'sourceMap',
      'importMultiple',
      'urlArgs',
      'javascriptEnabled',
      'pluginManager',
      'importantScope',
      'rewriteUrls' // option - whether to adjust URL's to be relative
  ];
  function isPathRelative(path) {
      return !/^(?:[a-z-]+:|\/|#)/i.test(path);
  }
  function isPathLocalRelative(path) {
      return path.charAt(0) === '.';
  }
  contexts.Eval = /** @class */ (function () {
      function Eval(options, frames) {
          copyFromOriginal(options, this, evalCopyProperties);
          if (typeof this.paths === 'string') {
              this.paths = [this.paths];
          }
          this.frames = frames || [];
          this.importantScope = this.importantScope || [];
          this.inCalc = false;
          this.mathOn = true;
      }
      Eval.prototype.enterCalc = function () {
          if (!this.calcStack) {
              this.calcStack = [];
          }
          this.calcStack.push(true);
          this.inCalc = true;
      };
      Eval.prototype.exitCalc = function () {
          this.calcStack.pop();
          if (!this.calcStack.length) {
              this.inCalc = false;
          }
      };
      Eval.prototype.inParenthesis = function () {
          if (!this.parensStack) {
              this.parensStack = [];
          }
          this.parensStack.push(true);
      };
      Eval.prototype.outOfParenthesis = function () {
          this.parensStack.pop();
      };
      Eval.prototype.isMathOn = function (op) {
          if (!this.mathOn) {
              return false;
          }
          if (op === '/' && this.math !== Math$1.ALWAYS && (!this.parensStack || !this.parensStack.length)) {
              return false;
          }
          if (this.math > Math$1.PARENS_DIVISION) {
              return this.parensStack && this.parensStack.length;
          }
          return true;
      };
      Eval.prototype.pathRequiresRewrite = function (path) {
          var isRelative = this.rewriteUrls === RewriteUrls.LOCAL ? isPathLocalRelative : isPathRelative;
          return isRelative(path);
      };
      Eval.prototype.rewritePath = function (path, rootpath) {
          var newPath;
          rootpath = rootpath || '';
          newPath = this.normalizePath(rootpath + path);
          // If a path was explicit relative and the rootpath was not an absolute path
          // we must ensure that the new path is also explicit relative.
          if (isPathLocalRelative(path) &&
              isPathRelative(rootpath) &&
              isPathLocalRelative(newPath) === false) {
              newPath = "./" + newPath;
          }
          return newPath;
      };
      Eval.prototype.normalizePath = function (path) {
          var segments = path.split('/').reverse();
          var segment;
          path = [];
          while (segments.length !== 0) {
              segment = segments.pop();
              switch (segment) {
                  case '.':
                      break;
                  case '..':
                      if ((path.length === 0) || (path[path.length - 1] === '..')) {
                          path.push(segment);
                      }
                      else {
                          path.pop();
                      }
                      break;
                  default:
                      path.push(segment);
                      break;
              }
          }
          return path.join('/');
      };
      return Eval;
  }());

  function makeRegistry(base) {
      return {
          _data: {},
          add: function (name, func) {
              // precautionary case conversion, as later querying of
              // the registry by function-caller uses lower case as well.
              name = name.toLowerCase();
              if (this._data.hasOwnProperty(name)) ;
              this._data[name] = func;
          },
          addMultiple: function (functions) {
              var _this = this;
              Object.keys(functions).forEach(function (name) {
                  _this.add(name, functions[name]);
              });
          },
          get: function (name) {
              return this._data[name] || (base && base.get(name));
          },
          getLocalFunctions: function () {
              return this._data;
          },
          inherit: function () {
              return makeRegistry(this);
          },
          create: function (base) {
              return makeRegistry(base);
          }
      };
  }
  var functionRegistry = makeRegistry(null);

  var defaultFunc = {
      eval: function () {
          var v = this.value_;
          var e = this.error_;
          if (e) {
              throw e;
          }
          if (v != null) {
              return v ? Keyword.True : Keyword.False;
          }
      },
      value: function (v) {
          this.value_ = v;
      },
      error: function (e) {
          this.error_ = e;
      },
      reset: function () {
          this.value_ = this.error_ = null;
      }
  };

  var Ruleset = /** @class */ (function (_super) {
      __extends(Ruleset, _super);
      function Ruleset(selectors, rules, strictImports, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this.selectors = selectors;
          _this.rules = rules;
          _this._lookups = {};
          _this._variables = null;
          _this._properties = null;
          _this.strictImports = strictImports;
          _this.copyVisibilityInfo(visibilityInfo);
          _this.allowRoot = true;
          _this.setParent(_this.selectors, _this);
          _this.setParent(_this.rules, _this);
          return _this;
      }
      Ruleset.prototype.isRulesetLike = function () {
          return true;
      };
      Ruleset.prototype.accept = function (visitor) {
          if (this.paths) {
              this.paths = visitor.visitArray(this.paths, true);
          }
          else if (this.selectors) {
              this.selectors = visitor.visitArray(this.selectors);
          }
          if (this.rules && this.rules.length) {
              this.rules = visitor.visitArray(this.rules);
          }
      };
      Ruleset.prototype.eval = function (context) {
          var selectors;
          var selCnt;
          var selector;
          var i;
          var hasVariable;
          var hasOnePassingSelector = false;
          if (this.selectors && (selCnt = this.selectors.length)) {
              selectors = new Array(selCnt);
              defaultFunc.error({
                  type: 'Syntax',
                  message: 'it is currently only allowed in parametric mixin guards,'
              });
              for (i = 0; i < selCnt; i++) {
                  selector = this.selectors[i].eval(context);
                  for (var j = 0; j < selector.elements.length; j++) {
                      if (selector.elements[j].isVariable) {
                          hasVariable = true;
                          break;
                      }
                  }
                  selectors[i] = selector;
                  if (selector.evaldCondition) {
                      hasOnePassingSelector = true;
                  }
              }
              if (hasVariable) {
                  var toParseSelectors = new Array(selCnt);
                  for (i = 0; i < selCnt; i++) {
                      selector = selectors[i];
                      toParseSelectors[i] = selector.toCSS(context);
                  }
                  this.parse.parseNode(toParseSelectors.join(','), ["selectors"], selectors[0].getIndex(), selectors[0].fileInfo(), function (err, result) {
                      if (result) {
                          selectors = flattenArray(result);
                      }
                  });
              }
              defaultFunc.reset();
          }
          else {
              hasOnePassingSelector = true;
          }
          var rules = this.rules ? copyArray(this.rules) : null;
          var ruleset = new Ruleset(selectors, rules, this.strictImports, this.visibilityInfo());
          var rule;
          var subRule;
          ruleset.originalRuleset = this;
          ruleset.root = this.root;
          ruleset.firstRoot = this.firstRoot;
          ruleset.allowImports = this.allowImports;
          if (this.debugInfo) {
              ruleset.debugInfo = this.debugInfo;
          }
          if (!hasOnePassingSelector) {
              rules.length = 0;
          }
          // inherit a function registry from the frames stack when possible;
          // otherwise from the global registry
          ruleset.functionRegistry = (function (frames) {
              var i = 0;
              var n = frames.length;
              var found;
              for (; i !== n; ++i) {
                  found = frames[i].functionRegistry;
                  if (found) {
                      return found;
                  }
              }
              return functionRegistry;
          })(context.frames).inherit();
          // push the current ruleset to the frames stack
          var ctxFrames = context.frames;
          ctxFrames.unshift(ruleset);
          // currrent selectors
          var ctxSelectors = context.selectors;
          if (!ctxSelectors) {
              context.selectors = ctxSelectors = [];
          }
          ctxSelectors.unshift(this.selectors);
          // Evaluate imports
          if (ruleset.root || ruleset.allowImports || !ruleset.strictImports) {
              ruleset.evalImports(context);
          }
          // Store the frames around mixin definitions,
          // so they can be evaluated like closures when the time comes.
          var rsRules = ruleset.rules;
          for (i = 0; (rule = rsRules[i]); i++) {
              if (rule.evalFirst) {
                  rsRules[i] = rule.eval(context);
              }
          }
          var mediaBlockCount = (context.mediaBlocks && context.mediaBlocks.length) || 0;
          // Evaluate mixin calls.
          for (i = 0; (rule = rsRules[i]); i++) {
              if (rule.type === 'MixinCall') {
                  /* jshint loopfunc:true */
                  rules = rule.eval(context).filter(function (r) {
                      if ((r instanceof Declaration) && r.variable) {
                          // do not pollute the scope if the variable is
                          // already there. consider returning false here
                          // but we need a way to "return" variable from mixins
                          return !(ruleset.variable(r.name));
                      }
                      return true;
                  });
                  rsRules.splice.apply(rsRules, [i, 1].concat(rules));
                  i += rules.length - 1;
                  ruleset.resetCache();
              }
              else if (rule.type === 'VariableCall') {
                  /* jshint loopfunc:true */
                  rules = rule.eval(context).rules.filter(function (r) {
                      if ((r instanceof Declaration) && r.variable) {
                          // do not pollute the scope at all
                          return false;
                      }
                      return true;
                  });
                  rsRules.splice.apply(rsRules, [i, 1].concat(rules));
                  i += rules.length - 1;
                  ruleset.resetCache();
              }
          }
          // Evaluate everything else
          for (i = 0; (rule = rsRules[i]); i++) {
              if (!rule.evalFirst) {
                  rsRules[i] = rule = rule.eval ? rule.eval(context) : rule;
              }
          }
          // Evaluate everything else
          for (i = 0; (rule = rsRules[i]); i++) {
              // for rulesets, check if it is a css guard and can be removed
              if (rule instanceof Ruleset && rule.selectors && rule.selectors.length === 1) {
                  // check if it can be folded in (e.g. & where)
                  if (rule.selectors[0] && rule.selectors[0].isJustParentSelector()) {
                      rsRules.splice(i--, 1);
                      for (var j = 0; (subRule = rule.rules[j]); j++) {
                          if (subRule instanceof Node) {
                              subRule.copyVisibilityInfo(rule.visibilityInfo());
                              if (!(subRule instanceof Declaration) || !subRule.variable) {
                                  rsRules.splice(++i, 0, subRule);
                              }
                          }
                      }
                  }
              }
          }
          // Pop the stack
          ctxFrames.shift();
          ctxSelectors.shift();
          if (context.mediaBlocks) {
              for (i = mediaBlockCount; i < context.mediaBlocks.length; i++) {
                  context.mediaBlocks[i].bubbleSelectors(selectors);
              }
          }
          return ruleset;
      };
      Ruleset.prototype.evalImports = function (context) {
          var rules = this.rules;
          var i;
          var importRules;
          if (!rules) {
              return;
          }
          for (i = 0; i < rules.length; i++) {
              if (rules[i].type === 'Import') {
                  importRules = rules[i].eval(context);
                  if (importRules && (importRules.length || importRules.length === 0)) {
                      rules.splice.apply(rules, [i, 1].concat(importRules));
                      i += importRules.length - 1;
                  }
                  else {
                      rules.splice(i, 1, importRules);
                  }
                  this.resetCache();
              }
          }
      };
      Ruleset.prototype.makeImportant = function () {
          var result = new Ruleset(this.selectors, this.rules.map(function (r) {
              if (r.makeImportant) {
                  return r.makeImportant();
              }
              else {
                  return r;
              }
          }), this.strictImports, this.visibilityInfo());
          return result;
      };
      Ruleset.prototype.matchArgs = function (args) {
          return !args || args.length === 0;
      };
      // lets you call a css selector with a guard
      Ruleset.prototype.matchCondition = function (args, context) {
          var lastSelector = this.selectors[this.selectors.length - 1];
          if (!lastSelector.evaldCondition) {
              return false;
          }
          if (lastSelector.condition &&
              !lastSelector.condition.eval(new contexts.Eval(context, context.frames))) {
              return false;
          }
          return true;
      };
      Ruleset.prototype.resetCache = function () {
          this._rulesets = null;
          this._variables = null;
          this._properties = null;
          this._lookups = {};
      };
      Ruleset.prototype.variables = function () {
          if (!this._variables) {
              this._variables = !this.rules ? {} : this.rules.reduce(function (hash, r) {
                  if (r instanceof Declaration && r.variable === true) {
                      hash[r.name] = r;
                  }
                  // when evaluating variables in an import statement, imports have not been eval'd
                  // so we need to go inside import statements.
                  // guard against root being a string (in the case of inlined less)
                  if (r.type === 'Import' && r.root && r.root.variables) {
                      var vars = r.root.variables();
                      for (var name_1 in vars) {
                          if (vars.hasOwnProperty(name_1)) {
                              hash[name_1] = r.root.variable(name_1);
                          }
                      }
                  }
                  return hash;
              }, {});
          }
          return this._variables;
      };
      Ruleset.prototype.properties = function () {
          if (!this._properties) {
              this._properties = !this.rules ? {} : this.rules.reduce(function (hash, r) {
                  if (r instanceof Declaration && r.variable !== true) {
                      var name_2 = (r.name.length === 1) && (r.name[0] instanceof Keyword) ?
                          r.name[0].value : r.name;
                      // Properties don't overwrite as they can merge
                      if (!hash["$" + name_2]) {
                          hash["$" + name_2] = [r];
                      }
                      else {
                          hash["$" + name_2].push(r);
                      }
                  }
                  return hash;
              }, {});
          }
          return this._properties;
      };
      Ruleset.prototype.variable = function (name) {
          var decl = this.variables()[name];
          if (decl) {
              return this.parseValue(decl);
          }
      };
      Ruleset.prototype.property = function (name) {
          var decl = this.properties()[name];
          if (decl) {
              return this.parseValue(decl);
          }
      };
      Ruleset.prototype.lastDeclaration = function () {
          for (var i_1 = this.rules.length; i_1 > 0; i_1--) {
              var decl = this.rules[i_1 - 1];
              if (decl instanceof Declaration) {
                  return this.parseValue(decl);
              }
          }
      };
      Ruleset.prototype.parseValue = function (toParse) {
          var self = this;
          function transformDeclaration(decl) {
              if (decl.value instanceof Anonymous && !decl.parsed) {
                  if (typeof decl.value.value === 'string') {
                      this.parse.parseNode(decl.value.value, ['value', 'important'], decl.value.getIndex(), decl.fileInfo(), function (err, result) {
                          if (err) {
                              decl.parsed = true;
                          }
                          if (result) {
                              decl.value = result[0];
                              decl.important = result[1] || '';
                              decl.parsed = true;
                          }
                      });
                  }
                  else {
                      decl.parsed = true;
                  }
                  return decl;
              }
              else {
                  return decl;
              }
          }
          if (!Array.isArray(toParse)) {
              return transformDeclaration.call(self, toParse);
          }
          else {
              var nodes_1 = [];
              toParse.forEach(function (n) {
                  nodes_1.push(transformDeclaration.call(self, n));
              });
              return nodes_1;
          }
      };
      Ruleset.prototype.rulesets = function () {
          if (!this.rules) {
              return [];
          }
          var filtRules = [];
          var rules = this.rules;
          var i;
          var rule;
          for (i = 0; (rule = rules[i]); i++) {
              if (rule.isRuleset) {
                  filtRules.push(rule);
              }
          }
          return filtRules;
      };
      Ruleset.prototype.prependRule = function (rule) {
          var rules = this.rules;
          if (rules) {
              rules.unshift(rule);
          }
          else {
              this.rules = [rule];
          }
          this.setParent(rule, this);
      };
      Ruleset.prototype.find = function (selector, self, filter) {
          if (self === void 0) { self = this; }
          var rules = [];
          var match;
          var foundMixins;
          var key = selector.toCSS();
          if (key in this._lookups) {
              return this._lookups[key];
          }
          this.rulesets().forEach(function (rule) {
              if (rule !== self) {
                  for (var j = 0; j < rule.selectors.length; j++) {
                      match = selector.match(rule.selectors[j]);
                      if (match) {
                          if (selector.elements.length > match) {
                              if (!filter || filter(rule)) {
                                  foundMixins = rule.find(new Selector(selector.elements.slice(match)), self, filter);
                                  for (var i_2 = 0; i_2 < foundMixins.length; ++i_2) {
                                      foundMixins[i_2].path.push(rule);
                                  }
                                  Array.prototype.push.apply(rules, foundMixins);
                              }
                          }
                          else {
                              rules.push({ rule: rule, path: [] });
                          }
                          break;
                      }
                  }
              }
          });
          this._lookups[key] = rules;
          return rules;
      };
      Ruleset.prototype.genCSS = function (context, output) {
          var i;
          var j;
          var charsetRuleNodes = [];
          var ruleNodes = [];
          var // Line number debugging
          debugInfo$1;
          var rule;
          var path;
          context.tabLevel = (context.tabLevel || 0);
          if (!this.root) {
              context.tabLevel++;
          }
          var tabRuleStr = context.compress ? '' : Array(context.tabLevel + 1).join('  ');
          var tabSetStr = context.compress ? '' : Array(context.tabLevel).join('  ');
          var sep;
          var charsetNodeIndex = 0;
          var importNodeIndex = 0;
          for (i = 0; (rule = this.rules[i]); i++) {
              if (rule instanceof Comment) {
                  if (importNodeIndex === i) {
                      importNodeIndex++;
                  }
                  ruleNodes.push(rule);
              }
              else if (rule.isCharset && rule.isCharset()) {
                  ruleNodes.splice(charsetNodeIndex, 0, rule);
                  charsetNodeIndex++;
                  importNodeIndex++;
              }
              else if (rule.type === 'Import') {
                  ruleNodes.splice(importNodeIndex, 0, rule);
                  importNodeIndex++;
              }
              else {
                  ruleNodes.push(rule);
              }
          }
          ruleNodes = charsetRuleNodes.concat(ruleNodes);
          // If this is the root node, we don't render
          // a selector, or {}.
          if (!this.root) {
              debugInfo$1 = debugInfo(context, this, tabSetStr);
              if (debugInfo$1) {
                  output.add(debugInfo$1);
                  output.add(tabSetStr);
              }
              var paths = this.paths;
              var pathCnt = paths.length;
              var pathSubCnt = void 0;
              sep = context.compress ? ',' : (",\n" + tabSetStr);
              for (i = 0; i < pathCnt; i++) {
                  path = paths[i];
                  if (!(pathSubCnt = path.length)) {
                      continue;
                  }
                  if (i > 0) {
                      output.add(sep);
                  }
                  context.firstSelector = true;
                  path[0].genCSS(context, output);
                  context.firstSelector = false;
                  for (j = 1; j < pathSubCnt; j++) {
                      path[j].genCSS(context, output);
                  }
              }
              output.add((context.compress ? '{' : ' {\n') + tabRuleStr);
          }
          // Compile rules and rulesets
          for (i = 0; (rule = ruleNodes[i]); i++) {
              if (i + 1 === ruleNodes.length) {
                  context.lastRule = true;
              }
              var currentLastRule = context.lastRule;
              if (rule.isRulesetLike(rule)) {
                  context.lastRule = false;
              }
              if (rule.genCSS) {
                  rule.genCSS(context, output);
              }
              else if (rule.value) {
                  output.add(rule.value.toString());
              }
              context.lastRule = currentLastRule;
              if (!context.lastRule && rule.isVisible()) {
                  output.add(context.compress ? '' : ("\n" + tabRuleStr));
              }
              else {
                  context.lastRule = false;
              }
          }
          if (!this.root) {
              output.add((context.compress ? '}' : "\n" + tabSetStr + "}"));
              context.tabLevel--;
          }
          if (!output.isEmpty() && !context.compress && this.firstRoot) {
              output.add('\n');
          }
      };
      Ruleset.prototype.joinSelectors = function (paths, context, selectors) {
          for (var s = 0; s < selectors.length; s++) {
              this.joinSelector(paths, context, selectors[s]);
          }
      };
      Ruleset.prototype.joinSelector = function (paths, context, selector) {
          function createParenthesis(elementsToPak, originalElement) {
              var replacementParen;
              var j;
              if (elementsToPak.length === 0) {
                  replacementParen = new Paren(elementsToPak[0]);
              }
              else {
                  var insideParent = new Array(elementsToPak.length);
                  for (j = 0; j < elementsToPak.length; j++) {
                      insideParent[j] = new Element(null, elementsToPak[j], originalElement.isVariable, originalElement._index, originalElement._fileInfo);
                  }
                  replacementParen = new Paren(new Selector(insideParent));
              }
              return replacementParen;
          }
          function createSelector(containedElement, originalElement) {
              var element;
              var selector;
              element = new Element(null, containedElement, originalElement.isVariable, originalElement._index, originalElement._fileInfo);
              selector = new Selector([element]);
              return selector;
          }
          // joins selector path from `beginningPath` with selector path in `addPath`
          // `replacedElement` contains element that is being replaced by `addPath`
          // returns concatenated path
          function addReplacementIntoPath(beginningPath, addPath, replacedElement, originalSelector) {
              var newSelectorPath;
              var lastSelector;
              var newJoinedSelector;
              // our new selector path
              newSelectorPath = [];
              // construct the joined selector - if & is the first thing this will be empty,
              // if not newJoinedSelector will be the last set of elements in the selector
              if (beginningPath.length > 0) {
                  newSelectorPath = copyArray(beginningPath);
                  lastSelector = newSelectorPath.pop();
                  newJoinedSelector = originalSelector.createDerived(copyArray(lastSelector.elements));
              }
              else {
                  newJoinedSelector = originalSelector.createDerived([]);
              }
              if (addPath.length > 0) {
                  // /deep/ is a CSS4 selector - (removed, so should deprecate)
                  // that is valid without anything in front of it
                  // so if the & does not have a combinator that is "" or " " then
                  // and there is a combinator on the parent, then grab that.
                  // this also allows + a { & .b { .a & { ... though not sure why you would want to do that
                  var combinator = replacedElement.combinator;
                  var parentEl = addPath[0].elements[0];
                  if (combinator.emptyOrWhitespace && !parentEl.combinator.emptyOrWhitespace) {
                      combinator = parentEl.combinator;
                  }
                  // join the elements so far with the first part of the parent
                  newJoinedSelector.elements.push(new Element(combinator, parentEl.value, replacedElement.isVariable, replacedElement._index, replacedElement._fileInfo));
                  newJoinedSelector.elements = newJoinedSelector.elements.concat(addPath[0].elements.slice(1));
              }
              // now add the joined selector - but only if it is not empty
              if (newJoinedSelector.elements.length !== 0) {
                  newSelectorPath.push(newJoinedSelector);
              }
              // put together the parent selectors after the join (e.g. the rest of the parent)
              if (addPath.length > 1) {
                  var restOfPath = addPath.slice(1);
                  restOfPath = restOfPath.map(function (selector) { return selector.createDerived(selector.elements, []); });
                  newSelectorPath = newSelectorPath.concat(restOfPath);
              }
              return newSelectorPath;
          }
          // joins selector path from `beginningPath` with every selector path in `addPaths` array
          // `replacedElement` contains element that is being replaced by `addPath`
          // returns array with all concatenated paths
          function addAllReplacementsIntoPath(beginningPath, addPaths, replacedElement, originalSelector, result) {
              var j;
              for (j = 0; j < beginningPath.length; j++) {
                  var newSelectorPath = addReplacementIntoPath(beginningPath[j], addPaths, replacedElement, originalSelector);
                  result.push(newSelectorPath);
              }
              return result;
          }
          function mergeElementsOnToSelectors(elements, selectors) {
              var i;
              var sel;
              if (elements.length === 0) {
                  return;
              }
              if (selectors.length === 0) {
                  selectors.push([new Selector(elements)]);
                  return;
              }
              for (i = 0; (sel = selectors[i]); i++) {
                  // if the previous thing in sel is a parent this needs to join on to it
                  if (sel.length > 0) {
                      sel[sel.length - 1] = sel[sel.length - 1].createDerived(sel[sel.length - 1].elements.concat(elements));
                  }
                  else {
                      sel.push(new Selector(elements));
                  }
              }
          }
          // replace all parent selectors inside `inSelector` by content of `context` array
          // resulting selectors are returned inside `paths` array
          // returns true if `inSelector` contained at least one parent selector
          function replaceParentSelector(paths, context, inSelector) {
              // The paths are [[Selector]]
              // The first list is a list of comma separated selectors
              // The inner list is a list of inheritance separated selectors
              // e.g.
              // .a, .b {
              //   .c {
              //   }
              // }
              // == [[.a] [.c]] [[.b] [.c]]
              //
              var i;
              var j;
              var k;
              var currentElements;
              var newSelectors;
              var selectorsMultiplied;
              var sel;
              var el;
              var hadParentSelector = false;
              var length;
              var lastSelector;
              function findNestedSelector(element) {
                  var maybeSelector;
                  if (!(element.value instanceof Paren)) {
                      return null;
                  }
                  maybeSelector = element.value.value;
                  if (!(maybeSelector instanceof Selector)) {
                      return null;
                  }
                  return maybeSelector;
              }
              // the elements from the current selector so far
              currentElements = [];
              // the current list of new selectors to add to the path.
              // We will build it up. We initiate it with one empty selector as we "multiply" the new selectors
              // by the parents
              newSelectors = [
                  []
              ];
              for (i = 0; (el = inSelector.elements[i]); i++) {
                  // non parent reference elements just get added
                  if (el.value !== '&') {
                      var nestedSelector = findNestedSelector(el);
                      if (nestedSelector != null) {
                          // merge the current list of non parent selector elements
                          // on to the current list of selectors to add
                          mergeElementsOnToSelectors(currentElements, newSelectors);
                          var nestedPaths = [];
                          var replaced = void 0;
                          var replacedNewSelectors = [];
                          replaced = replaceParentSelector(nestedPaths, context, nestedSelector);
                          hadParentSelector = hadParentSelector || replaced;
                          // the nestedPaths array should have only one member - replaceParentSelector does not multiply selectors
                          for (k = 0; k < nestedPaths.length; k++) {
                              var replacementSelector = createSelector(createParenthesis(nestedPaths[k], el), el);
                              addAllReplacementsIntoPath(newSelectors, [replacementSelector], el, inSelector, replacedNewSelectors);
                          }
                          newSelectors = replacedNewSelectors;
                          currentElements = [];
                      }
                      else {
                          currentElements.push(el);
                      }
                  }
                  else {
                      hadParentSelector = true;
                      // the new list of selectors to add
                      selectorsMultiplied = [];
                      // merge the current list of non parent selector elements
                      // on to the current list of selectors to add
                      mergeElementsOnToSelectors(currentElements, newSelectors);
                      // loop through our current selectors
                      for (j = 0; j < newSelectors.length; j++) {
                          sel = newSelectors[j];
                          // if we don't have any parent paths, the & might be in a mixin so that it can be used
                          // whether there are parents or not
                          if (context.length === 0) {
                              // the combinator used on el should now be applied to the next element instead so that
                              // it is not lost
                              if (sel.length > 0) {
                                  sel[0].elements.push(new Element(el.combinator, '', el.isVariable, el._index, el._fileInfo));
                              }
                              selectorsMultiplied.push(sel);
                          }
                          else {
                              // and the parent selectors
                              for (k = 0; k < context.length; k++) {
                                  // We need to put the current selectors
                                  // then join the last selector's elements on to the parents selectors
                                  var newSelectorPath = addReplacementIntoPath(sel, context[k], el, inSelector);
                                  // add that to our new set of selectors
                                  selectorsMultiplied.push(newSelectorPath);
                              }
                          }
                      }
                      // our new selectors has been multiplied, so reset the state
                      newSelectors = selectorsMultiplied;
                      currentElements = [];
                  }
              }
              // if we have any elements left over (e.g. .a& .b == .b)
              // add them on to all the current selectors
              mergeElementsOnToSelectors(currentElements, newSelectors);
              for (i = 0; i < newSelectors.length; i++) {
                  length = newSelectors[i].length;
                  if (length > 0) {
                      paths.push(newSelectors[i]);
                      lastSelector = newSelectors[i][length - 1];
                      newSelectors[i][length - 1] = lastSelector.createDerived(lastSelector.elements, inSelector.extendList);
                  }
              }
              return hadParentSelector;
          }
          function deriveSelector(visibilityInfo, deriveFrom) {
              var newSelector = deriveFrom.createDerived(deriveFrom.elements, deriveFrom.extendList, deriveFrom.evaldCondition);
              newSelector.copyVisibilityInfo(visibilityInfo);
              return newSelector;
          }
          // joinSelector code follows
          var i;
          var newPaths;
          var hadParentSelector;
          newPaths = [];
          hadParentSelector = replaceParentSelector(newPaths, context, selector);
          if (!hadParentSelector) {
              if (context.length > 0) {
                  newPaths = [];
                  for (i = 0; i < context.length; i++) {
                      var concatenated = context[i].map(deriveSelector.bind(this, selector.visibilityInfo()));
                      concatenated.push(selector);
                      newPaths.push(concatenated);
                  }
              }
              else {
                  newPaths = [[selector]];
              }
          }
          for (i = 0; i < newPaths.length; i++) {
              paths.push(newPaths[i]);
          }
      };
      return Ruleset;
  }(Node));
  Ruleset.prototype.type = 'Ruleset';
  Ruleset.prototype.isRuleset = true;

  var AtRule = /** @class */ (function (_super) {
      __extends(AtRule, _super);
      function AtRule(name, value, rules, index, currentFileInfo, debugInfo, isRooted, visibilityInfo) {
          var _this = _super.call(this) || this;
          var i;
          _this.name = name;
          _this.value = (value instanceof Node) ? value : (value ? new Anonymous(value) : value);
          if (rules) {
              if (Array.isArray(rules)) {
                  _this.rules = rules;
              }
              else {
                  _this.rules = [rules];
                  _this.rules[0].selectors = (new Selector([], null, null, index, currentFileInfo)).createEmptySelectors();
              }
              for (i = 0; i < _this.rules.length; i++) {
                  _this.rules[i].allowImports = true;
              }
              _this.setParent(_this.rules, _this);
          }
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.debugInfo = debugInfo;
          _this.isRooted = isRooted || false;
          _this.copyVisibilityInfo(visibilityInfo);
          _this.allowRoot = true;
          return _this;
      }
      AtRule.prototype.accept = function (visitor) {
          var value = this.value;
          var rules = this.rules;
          if (rules) {
              this.rules = visitor.visitArray(rules);
          }
          if (value) {
              this.value = visitor.visit(value);
          }
      };
      AtRule.prototype.isRulesetLike = function () {
          return this.rules || !this.isCharset();
      };
      AtRule.prototype.isCharset = function () {
          return '@charset' === this.name;
      };
      AtRule.prototype.genCSS = function (context, output) {
          var value = this.value;
          var rules = this.rules;
          output.add(this.name, this.fileInfo(), this.getIndex());
          if (value) {
              output.add(' ');
              value.genCSS(context, output);
          }
          if (rules) {
              this.outputRuleset(context, output, rules);
          }
          else {
              output.add(';');
          }
      };
      AtRule.prototype.eval = function (context) {
          var mediaPathBackup;
          var mediaBlocksBackup;
          var value = this.value;
          var rules = this.rules;
          // media stored inside other atrule should not bubble over it
          // backpup media bubbling information
          mediaPathBackup = context.mediaPath;
          mediaBlocksBackup = context.mediaBlocks;
          // deleted media bubbling information
          context.mediaPath = [];
          context.mediaBlocks = [];
          if (value) {
              value = value.eval(context);
          }
          if (rules) {
              // assuming that there is only one rule at this point - that is how parser constructs the rule
              rules = [rules[0].eval(context)];
              rules[0].root = true;
          }
          // restore media bubbling information
          context.mediaPath = mediaPathBackup;
          context.mediaBlocks = mediaBlocksBackup;
          return new AtRule(this.name, value, rules, this.getIndex(), this.fileInfo(), this.debugInfo, this.isRooted, this.visibilityInfo());
      };
      AtRule.prototype.variable = function (name) {
          if (this.rules) {
              // assuming that there is only one rule at this point - that is how parser constructs the rule
              return Ruleset.prototype.variable.call(this.rules[0], name);
          }
      };
      AtRule.prototype.find = function () {
          var args = [];
          for (var _i = 0; _i < arguments.length; _i++) {
              args[_i] = arguments[_i];
          }
          if (this.rules) {
              // assuming that there is only one rule at this point - that is how parser constructs the rule
              return Ruleset.prototype.find.apply(this.rules[0], args);
          }
      };
      AtRule.prototype.rulesets = function () {
          if (this.rules) {
              // assuming that there is only one rule at this point - that is how parser constructs the rule
              return Ruleset.prototype.rulesets.apply(this.rules[0]);
          }
      };
      AtRule.prototype.outputRuleset = function (context, output, rules) {
          var ruleCnt = rules.length;
          var i;
          context.tabLevel = (context.tabLevel | 0) + 1;
          // Compressed
          if (context.compress) {
              output.add('{');
              for (i = 0; i < ruleCnt; i++) {
                  rules[i].genCSS(context, output);
              }
              output.add('}');
              context.tabLevel--;
              return;
          }
          // Non-compressed
          var tabSetStr = "\n" + Array(context.tabLevel).join('  ');
          var tabRuleStr = tabSetStr + "  ";
          if (!ruleCnt) {
              output.add(" {" + tabSetStr + "}");
          }
          else {
              output.add(" {" + tabRuleStr);
              rules[0].genCSS(context, output);
              for (i = 1; i < ruleCnt; i++) {
                  output.add(tabRuleStr);
                  rules[i].genCSS(context, output);
              }
              output.add(tabSetStr + "}");
          }
          context.tabLevel--;
      };
      return AtRule;
  }(Node));
  AtRule.prototype.type = 'AtRule';

  var DetachedRuleset = /** @class */ (function (_super) {
      __extends(DetachedRuleset, _super);
      function DetachedRuleset(ruleset, frames) {
          var _this = _super.call(this) || this;
          _this.ruleset = ruleset;
          _this.frames = frames;
          _this.setParent(_this.ruleset, _this);
          return _this;
      }
      DetachedRuleset.prototype.accept = function (visitor) {
          this.ruleset = visitor.visit(this.ruleset);
      };
      DetachedRuleset.prototype.eval = function (context) {
          var frames = this.frames || copyArray(context.frames);
          return new DetachedRuleset(this.ruleset, frames);
      };
      DetachedRuleset.prototype.callEval = function (context) {
          return this.ruleset.eval(this.frames ? new contexts.Eval(context, this.frames.concat(context.frames)) : context);
      };
      return DetachedRuleset;
  }(Node));
  DetachedRuleset.prototype.type = 'DetachedRuleset';
  DetachedRuleset.prototype.evalFirst = true;

  var Unit = /** @class */ (function (_super) {
      __extends(Unit, _super);
      function Unit(numerator, denominator, backupUnit) {
          var _this = _super.call(this) || this;
          _this.numerator = numerator ? copyArray(numerator).sort() : [];
          _this.denominator = denominator ? copyArray(denominator).sort() : [];
          if (backupUnit) {
              _this.backupUnit = backupUnit;
          }
          else if (numerator && numerator.length) {
              _this.backupUnit = numerator[0];
          }
          return _this;
      }
      Unit.prototype.clone = function () {
          return new Unit(copyArray(this.numerator), copyArray(this.denominator), this.backupUnit);
      };
      Unit.prototype.genCSS = function (context, output) {
          // Dimension checks the unit is singular and throws an error if in strict math mode.
          var strictUnits = context && context.strictUnits;
          if (this.numerator.length === 1) {
              output.add(this.numerator[0]); // the ideal situation
          }
          else if (!strictUnits && this.backupUnit) {
              output.add(this.backupUnit);
          }
          else if (!strictUnits && this.denominator.length) {
              output.add(this.denominator[0]);
          }
      };
      Unit.prototype.toString = function () {
          var i;
          var returnStr = this.numerator.join('*');
          for (i = 0; i < this.denominator.length; i++) {
              returnStr += "/" + this.denominator[i];
          }
          return returnStr;
      };
      Unit.prototype.compare = function (other) {
          return this.is(other.toString()) ? 0 : undefined;
      };
      Unit.prototype.is = function (unitString) {
          return this.toString().toUpperCase() === unitString.toUpperCase();
      };
      Unit.prototype.isLength = function () {
          return RegExp('^(px|em|ex|ch|rem|in|cm|mm|pc|pt|ex|vw|vh|vmin|vmax)$', 'gi').test(this.toCSS());
      };
      Unit.prototype.isEmpty = function () {
          return this.numerator.length === 0 && this.denominator.length === 0;
      };
      Unit.prototype.isSingular = function () {
          return this.numerator.length <= 1 && this.denominator.length === 0;
      };
      Unit.prototype.map = function (callback) {
          var i;
          for (i = 0; i < this.numerator.length; i++) {
              this.numerator[i] = callback(this.numerator[i], false);
          }
          for (i = 0; i < this.denominator.length; i++) {
              this.denominator[i] = callback(this.denominator[i], true);
          }
      };
      Unit.prototype.usedUnits = function () {
          var group;
          var result = {};
          var mapUnit;
          var groupName;
          mapUnit = function (atomicUnit) {
              /* jshint loopfunc:true */
              if (group.hasOwnProperty(atomicUnit) && !result[groupName]) {
                  result[groupName] = atomicUnit;
              }
              return atomicUnit;
          };
          for (groupName in unitConversions) {
              if (unitConversions.hasOwnProperty(groupName)) {
                  group = unitConversions[groupName];
                  this.map(mapUnit);
              }
          }
          return result;
      };
      Unit.prototype.cancel = function () {
          var counter = {};
          var atomicUnit;
          var i;
          for (i = 0; i < this.numerator.length; i++) {
              atomicUnit = this.numerator[i];
              counter[atomicUnit] = (counter[atomicUnit] || 0) + 1;
          }
          for (i = 0; i < this.denominator.length; i++) {
              atomicUnit = this.denominator[i];
              counter[atomicUnit] = (counter[atomicUnit] || 0) - 1;
          }
          this.numerator = [];
          this.denominator = [];
          for (atomicUnit in counter) {
              if (counter.hasOwnProperty(atomicUnit)) {
                  var count = counter[atomicUnit];
                  if (count > 0) {
                      for (i = 0; i < count; i++) {
                          this.numerator.push(atomicUnit);
                      }
                  }
                  else if (count < 0) {
                      for (i = 0; i < -count; i++) {
                          this.denominator.push(atomicUnit);
                      }
                  }
              }
          }
          this.numerator.sort();
          this.denominator.sort();
      };
      return Unit;
  }(Node));
  Unit.prototype.type = 'Unit';

  //
  // A number with a unit
  //
  var Dimension = /** @class */ (function (_super) {
      __extends(Dimension, _super);
      function Dimension(value, unit) {
          var _this = _super.call(this) || this;
          _this.value = parseFloat(value);
          if (isNaN(_this.value)) {
              throw new Error('Dimension is not a number.');
          }
          _this.unit = (unit && unit instanceof Unit) ? unit :
              new Unit(unit ? [unit] : undefined);
          _this.setParent(_this.unit, _this);
          return _this;
      }
      Dimension.prototype.accept = function (visitor) {
          this.unit = visitor.visit(this.unit);
      };
      Dimension.prototype.eval = function (context) {
          return this;
      };
      Dimension.prototype.toColor = function () {
          return new Color([this.value, this.value, this.value]);
      };
      Dimension.prototype.genCSS = function (context, output) {
          if ((context && context.strictUnits) && !this.unit.isSingular()) {
              throw new Error("Multiple units in dimension. Correct the units or use the unit function. Bad unit: " + this.unit.toString());
          }
          var value = this.fround(context, this.value);
          var strValue = String(value);
          if (value !== 0 && value < 0.000001 && value > -0.000001) {
              // would be output 1e-6 etc.
              strValue = value.toFixed(20).replace(/0+$/, '');
          }
          if (context && context.compress) {
              // Zero values doesn't need a unit
              if (value === 0 && this.unit.isLength()) {
                  output.add(strValue);
                  return;
              }
              // Float values doesn't need a leading zero
              if (value > 0 && value < 1) {
                  strValue = (strValue).substr(1);
              }
          }
          output.add(strValue);
          this.unit.genCSS(context, output);
      };
      // In an operation between two Dimensions,
      // we default to the first Dimension's unit,
      // so `1px + 2` will yield `3px`.
      Dimension.prototype.operate = function (context, op, other) {
          /* jshint noempty:false */
          var value = this._operate(context, op, this.value, other.value);
          var unit = this.unit.clone();
          if (op === '+' || op === '-') {
              if (unit.numerator.length === 0 && unit.denominator.length === 0) {
                  unit = other.unit.clone();
                  if (this.unit.backupUnit) {
                      unit.backupUnit = this.unit.backupUnit;
                  }
              }
              else if (other.unit.numerator.length === 0 && unit.denominator.length === 0) ;
              else {
                  other = other.convertTo(this.unit.usedUnits());
                  if (context.strictUnits && other.unit.toString() !== unit.toString()) {
                      throw new Error("Incompatible units. Change the units or use the unit function. " +
                          ("Bad units: '" + unit.toString() + "' and '" + other.unit.toString() + "'."));
                  }
                  value = this._operate(context, op, this.value, other.value);
              }
          }
          else if (op === '*') {
              unit.numerator = unit.numerator.concat(other.unit.numerator).sort();
              unit.denominator = unit.denominator.concat(other.unit.denominator).sort();
              unit.cancel();
          }
          else if (op === '/') {
              unit.numerator = unit.numerator.concat(other.unit.denominator).sort();
              unit.denominator = unit.denominator.concat(other.unit.numerator).sort();
              unit.cancel();
          }
          return new Dimension(value, unit);
      };
      Dimension.prototype.compare = function (other) {
          var a;
          var b;
          if (!(other instanceof Dimension)) {
              return undefined;
          }
          if (this.unit.isEmpty() || other.unit.isEmpty()) {
              a = this;
              b = other;
          }
          else {
              a = this.unify();
              b = other.unify();
              if (a.unit.compare(b.unit) !== 0) {
                  return undefined;
              }
          }
          return Node.numericCompare(a.value, b.value);
      };
      Dimension.prototype.unify = function () {
          return this.convertTo({ length: 'px', duration: 's', angle: 'rad' });
      };
      Dimension.prototype.convertTo = function (conversions) {
          var value = this.value;
          var unit = this.unit.clone();
          var i;
          var groupName;
          var group;
          var targetUnit;
          var derivedConversions = {};
          var applyUnit;
          if (typeof conversions === 'string') {
              for (i in unitConversions) {
                  if (unitConversions[i].hasOwnProperty(conversions)) {
                      derivedConversions = {};
                      derivedConversions[i] = conversions;
                  }
              }
              conversions = derivedConversions;
          }
          applyUnit = function (atomicUnit, denominator) {
              /* jshint loopfunc:true */
              if (group.hasOwnProperty(atomicUnit)) {
                  if (denominator) {
                      value = value / (group[atomicUnit] / group[targetUnit]);
                  }
                  else {
                      value = value * (group[atomicUnit] / group[targetUnit]);
                  }
                  return targetUnit;
              }
              return atomicUnit;
          };
          for (groupName in conversions) {
              if (conversions.hasOwnProperty(groupName)) {
                  targetUnit = conversions[groupName];
                  group = unitConversions[groupName];
                  unit.map(applyUnit);
              }
          }
          unit.cancel();
          return new Dimension(value, unit);
      };
      return Dimension;
  }(Node));
  Dimension.prototype.type = 'Dimension';

  var MATH$1 = Math$1;
  var Operation = /** @class */ (function (_super) {
      __extends(Operation, _super);
      function Operation(op, operands, isSpaced) {
          var _this = _super.call(this) || this;
          _this.op = op.trim();
          _this.operands = operands;
          _this.isSpaced = isSpaced;
          return _this;
      }
      Operation.prototype.accept = function (visitor) {
          this.operands = visitor.visitArray(this.operands);
      };
      Operation.prototype.eval = function (context) {
          var a = this.operands[0].eval(context);
          var b = this.operands[1].eval(context);
          var op;
          if (context.isMathOn(this.op)) {
              op = this.op === './' ? '/' : this.op;
              if (a instanceof Dimension && b instanceof Color) {
                  a = a.toColor();
              }
              if (b instanceof Dimension && a instanceof Color) {
                  b = b.toColor();
              }
              if (!a.operate) {
                  if (a instanceof Operation && a.op === '/' && context.math === MATH$1.PARENS_DIVISION) {
                      return new Operation(this.op, [a, b], this.isSpaced);
                  }
                  throw { type: 'Operation',
                      message: 'Operation on an invalid type' };
              }
              return a.operate(context, op, b);
          }
          else {
              return new Operation(this.op, [a, b], this.isSpaced);
          }
      };
      Operation.prototype.genCSS = function (context, output) {
          this.operands[0].genCSS(context, output);
          if (this.isSpaced) {
              output.add(' ');
          }
          output.add(this.op);
          if (this.isSpaced) {
              output.add(' ');
          }
          this.operands[1].genCSS(context, output);
      };
      return Operation;
  }(Node));
  Operation.prototype.type = 'Operation';

  var MATH$2 = Math$1;
  var Expression = /** @class */ (function (_super) {
      __extends(Expression, _super);
      function Expression(value, noSpacing) {
          var _this = _super.call(this) || this;
          _this.value = value;
          _this.noSpacing = noSpacing;
          if (!value) {
              throw new Error('Expression requires an array parameter');
          }
          return _this;
      }
      Expression.prototype.accept = function (visitor) {
          this.value = visitor.visitArray(this.value);
      };
      Expression.prototype.eval = function (context) {
          var returnValue;
          var mathOn = context.isMathOn();
          var inParenthesis = this.parens &&
              (context.math !== MATH$2.STRICT_LEGACY || !this.parensInOp);
          var doubleParen = false;
          if (inParenthesis) {
              context.inParenthesis();
          }
          if (this.value.length > 1) {
              returnValue = new Expression(this.value.map(function (e) {
                  if (!e.eval) {
                      return e;
                  }
                  return e.eval(context);
              }), this.noSpacing);
          }
          else if (this.value.length === 1) {
              if (this.value[0].parens && !this.value[0].parensInOp && !context.inCalc) {
                  doubleParen = true;
              }
              returnValue = this.value[0].eval(context);
          }
          else {
              returnValue = this;
          }
          if (inParenthesis) {
              context.outOfParenthesis();
          }
          if (this.parens && this.parensInOp && !mathOn && !doubleParen
              && (!(returnValue instanceof Dimension))) {
              returnValue = new Paren(returnValue);
          }
          return returnValue;
      };
      Expression.prototype.genCSS = function (context, output) {
          for (var i_1 = 0; i_1 < this.value.length; i_1++) {
              this.value[i_1].genCSS(context, output);
              if (!this.noSpacing && i_1 + 1 < this.value.length) {
                  output.add(' ');
              }
          }
      };
      Expression.prototype.throwAwayComments = function () {
          this.value = this.value.filter(function (v) { return !(v instanceof Comment); });
      };
      return Expression;
  }(Node));
  Expression.prototype.type = 'Expression';

  var functionCaller = /** @class */ (function () {
      function functionCaller(name, context, index, currentFileInfo) {
          this.name = name.toLowerCase();
          this.index = index;
          this.context = context;
          this.currentFileInfo = currentFileInfo;
          this.func = context.frames[0].functionRegistry.get(this.name);
      }
      functionCaller.prototype.isValid = function () {
          return Boolean(this.func);
      };
      functionCaller.prototype.call = function (args) {
          // This code is terrible and should be replaced as per this issue...
          // https://github.com/less/less.js/issues/2477
          if (Array.isArray(args)) {
              args = args.filter(function (item) {
                  if (item.type === 'Comment') {
                      return false;
                  }
                  return true;
              })
                  .map(function (item) {
                  if (item.type === 'Expression') {
                      var subNodes = item.value.filter(function (item) {
                          if (item.type === 'Comment') {
                              return false;
                          }
                          return true;
                      });
                      if (subNodes.length === 1) {
                          return subNodes[0];
                      }
                      else {
                          return new Expression(subNodes);
                      }
                  }
                  return item;
              });
          }
          return this.func.apply(this, args);
      };
      return functionCaller;
  }());

  //
  // A function call node.
  //
  var Call = /** @class */ (function (_super) {
      __extends(Call, _super);
      function Call(name, args, index, currentFileInfo) {
          var _this = _super.call(this) || this;
          _this.name = name;
          _this.args = args;
          _this.calc = name === 'calc';
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          return _this;
      }
      Call.prototype.accept = function (visitor) {
          if (this.args) {
              this.args = visitor.visitArray(this.args);
          }
      };
      //
      // When evaluating a function call,
      // we either find the function in the functionRegistry,
      // in which case we call it, passing the  evaluated arguments,
      // if this returns null or we cannot find the function, we
      // simply print it out as it appeared originally [2].
      //
      // The reason why we evaluate the arguments, is in the case where
      // we try to pass a variable to a function, like: `saturate(@color)`.
      // The function should receive the value, not the variable.
      //
      Call.prototype.eval = function (context) {
          /**
           * Turn off math for calc(), and switch back on for evaluating nested functions
           */
          var currentMathContext = context.mathOn;
          context.mathOn = !this.calc;
          if (this.calc || context.inCalc) {
              context.enterCalc();
          }
          var args = this.args.map(function (a) { return a.eval(context); });
          if (this.calc || context.inCalc) {
              context.exitCalc();
          }
          context.mathOn = currentMathContext;
          var result;
          var funcCaller = new functionCaller(this.name, context, this.getIndex(), this.fileInfo());
          if (funcCaller.isValid()) {
              try {
                  result = funcCaller.call(args);
              }
              catch (e) {
                  throw {
                      type: e.type || 'Runtime',
                      message: "error evaluating function `" + this.name + "`" + (e.message ? ": " + e.message : ''),
                      index: this.getIndex(),
                      filename: this.fileInfo().filename,
                      line: e.lineNumber,
                      column: e.columnNumber
                  };
              }
              if (result !== null && result !== undefined) {
                  // Results that that are not nodes are cast as Anonymous nodes
                  // Falsy values or booleans are returned as empty nodes
                  if (!(result instanceof Node)) {
                      if (!result || result === true) {
                          result = new Anonymous(null);
                      }
                      else {
                          result = new Anonymous(result.toString());
                      }
                  }
                  result._index = this._index;
                  result._fileInfo = this._fileInfo;
                  return result;
              }
          }
          return new Call(this.name, args, this.getIndex(), this.fileInfo());
      };
      Call.prototype.genCSS = function (context, output) {
          output.add(this.name + "(", this.fileInfo(), this.getIndex());
          for (var i_1 = 0; i_1 < this.args.length; i_1++) {
              this.args[i_1].genCSS(context, output);
              if (i_1 + 1 < this.args.length) {
                  output.add(', ');
              }
          }
          output.add(')');
      };
      return Call;
  }(Node));
  Call.prototype.type = 'Call';

  var Variable = /** @class */ (function (_super) {
      __extends(Variable, _super);
      function Variable(name, index, currentFileInfo) {
          var _this = _super.call(this) || this;
          _this.name = name;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          return _this;
      }
      Variable.prototype.eval = function (context) {
          var variable;
          var name = this.name;
          if (name.indexOf('@@') === 0) {
              name = "@" + new Variable(name.slice(1), this.getIndex(), this.fileInfo()).eval(context).value;
          }
          if (this.evaluating) {
              throw { type: 'Name',
                  message: "Recursive variable definition for " + name,
                  filename: this.fileInfo().filename,
                  index: this.getIndex() };
          }
          this.evaluating = true;
          variable = this.find(context.frames, function (frame) {
              var v = frame.variable(name);
              if (v) {
                  if (v.important) {
                      var importantScope = context.importantScope[context.importantScope.length - 1];
                      importantScope.important = v.important;
                  }
                  // If in calc, wrap vars in a function call to cascade evaluate args first
                  if (context.inCalc) {
                      return (new Call('_SELF', [v.value])).eval(context);
                  }
                  else {
                      return v.value.eval(context);
                  }
              }
          });
          if (variable) {
              this.evaluating = false;
              return variable;
          }
          else {
              throw { type: 'Name',
                  message: "variable " + name + " is undefined",
                  filename: this.fileInfo().filename,
                  index: this.getIndex() };
          }
      };
      Variable.prototype.find = function (obj, fun) {
          for (var i_1 = 0, r = void 0; i_1 < obj.length; i_1++) {
              r = fun.call(obj, obj[i_1]);
              if (r) {
                  return r;
              }
          }
          return null;
      };
      return Variable;
  }(Node));
  Variable.prototype.type = 'Variable';

  var Property = /** @class */ (function (_super) {
      __extends(Property, _super);
      function Property(name, index, currentFileInfo) {
          var _this = _super.call(this) || this;
          _this.name = name;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          return _this;
      }
      Property.prototype.eval = function (context) {
          var property;
          var name = this.name;
          // TODO: shorten this reference
          var mergeRules = context.pluginManager.less.visitors.ToCSSVisitor.prototype._mergeRules;
          if (this.evaluating) {
              throw { type: 'Name',
                  message: "Recursive property reference for " + name,
                  filename: this.fileInfo().filename,
                  index: this.getIndex() };
          }
          this.evaluating = true;
          property = this.find(context.frames, function (frame) {
              var v;
              var vArr = frame.property(name);
              if (vArr) {
                  for (var i_1 = 0; i_1 < vArr.length; i_1++) {
                      v = vArr[i_1];
                      vArr[i_1] = new Declaration(v.name, v.value, v.important, v.merge, v.index, v.currentFileInfo, v.inline, v.variable);
                  }
                  mergeRules(vArr);
                  v = vArr[vArr.length - 1];
                  if (v.important) {
                      var importantScope = context.importantScope[context.importantScope.length - 1];
                      importantScope.important = v.important;
                  }
                  v = v.value.eval(context);
                  return v;
              }
          });
          if (property) {
              this.evaluating = false;
              return property;
          }
          else {
              throw { type: 'Name',
                  message: "Property '" + name + "' is undefined",
                  filename: this.currentFileInfo.filename,
                  index: this.index };
          }
      };
      Property.prototype.find = function (obj, fun) {
          for (var i_2 = 0, r = void 0; i_2 < obj.length; i_2++) {
              r = fun.call(obj, obj[i_2]);
              if (r) {
                  return r;
              }
          }
          return null;
      };
      return Property;
  }(Node));
  Property.prototype.type = 'Property';

  var Attribute = /** @class */ (function (_super) {
      __extends(Attribute, _super);
      function Attribute(key, op, value) {
          var _this = _super.call(this) || this;
          _this.key = key;
          _this.op = op;
          _this.value = value;
          return _this;
      }
      Attribute.prototype.eval = function (context) {
          return new Attribute(this.key.eval ? this.key.eval(context) : this.key, this.op, (this.value && this.value.eval) ? this.value.eval(context) : this.value);
      };
      Attribute.prototype.genCSS = function (context, output) {
          output.add(this.toCSS(context));
      };
      Attribute.prototype.toCSS = function (context) {
          var value = this.key.toCSS ? this.key.toCSS(context) : this.key;
          if (this.op) {
              value += this.op;
              value += (this.value.toCSS ? this.value.toCSS(context) : this.value);
          }
          return "[" + value + "]";
      };
      return Attribute;
  }(Node));
  Attribute.prototype.type = 'Attribute';

  var Quoted = /** @class */ (function (_super) {
      __extends(Quoted, _super);
      function Quoted(str, content, escaped, index, currentFileInfo) {
          var _this = _super.call(this) || this;
          _this.escaped = (escaped == null) ? true : escaped;
          _this.value = content || '';
          _this.quote = str.charAt(0);
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.variableRegex = /@\{([\w-]+)\}/g;
          _this.propRegex = /\$\{([\w-]+)\}/g;
          _this.allowRoot = escaped;
          return _this;
      }
      Quoted.prototype.genCSS = function (context, output) {
          if (!this.escaped) {
              output.add(this.quote, this.fileInfo(), this.getIndex());
          }
          output.add(this.value);
          if (!this.escaped) {
              output.add(this.quote);
          }
      };
      Quoted.prototype.containsVariables = function () {
          return this.value.match(this.variableRegex);
      };
      Quoted.prototype.eval = function (context) {
          var that = this;
          var value = this.value;
          var variableReplacement = function (_, name) {
              var v = new Variable("@" + name, that.getIndex(), that.fileInfo()).eval(context, true);
              return (v instanceof Quoted) ? v.value : v.toCSS();
          };
          var propertyReplacement = function (_, name) {
              var v = new Property("$" + name, that.getIndex(), that.fileInfo()).eval(context, true);
              return (v instanceof Quoted) ? v.value : v.toCSS();
          };
          function iterativeReplace(value, regexp, replacementFnc) {
              var evaluatedValue = value;
              do {
                  value = evaluatedValue.toString();
                  evaluatedValue = value.replace(regexp, replacementFnc);
              } while (value !== evaluatedValue);
              return evaluatedValue;
          }
          value = iterativeReplace(value, this.variableRegex, variableReplacement);
          value = iterativeReplace(value, this.propRegex, propertyReplacement);
          return new Quoted(this.quote + value + this.quote, value, this.escaped, this.getIndex(), this.fileInfo());
      };
      Quoted.prototype.compare = function (other) {
          // when comparing quoted strings allow the quote to differ
          if (other.type === 'Quoted' && !this.escaped && !other.escaped) {
              return Node.numericCompare(this.value, other.value);
          }
          else {
              return other.toCSS && this.toCSS() === other.toCSS() ? 0 : undefined;
          }
      };
      return Quoted;
  }(Node));
  Quoted.prototype.type = 'Quoted';

  var URL = /** @class */ (function (_super) {
      __extends(URL, _super);
      function URL(val, index, currentFileInfo, isEvald) {
          var _this = _super.call(this) || this;
          _this.value = val;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.isEvald = isEvald;
          return _this;
      }
      URL.prototype.accept = function (visitor) {
          this.value = visitor.visit(this.value);
      };
      URL.prototype.genCSS = function (context, output) {
          output.add('url(');
          this.value.genCSS(context, output);
          output.add(')');
      };
      URL.prototype.eval = function (context) {
          var val = this.value.eval(context);
          var rootpath;
          if (!this.isEvald) {
              // Add the rootpath if the URL requires a rewrite
              rootpath = this.fileInfo() && this.fileInfo().rootpath;
              if (typeof rootpath === 'string' &&
                  typeof val.value === 'string' &&
                  context.pathRequiresRewrite(val.value)) {
                  if (!val.quote) {
                      rootpath = escapePath(rootpath);
                  }
                  val.value = context.rewritePath(val.value, rootpath);
              }
              else {
                  val.value = context.normalizePath(val.value);
              }
              // Add url args if enabled
              if (context.urlArgs) {
                  if (!val.value.match(/^\s*data:/)) {
                      var delimiter = val.value.indexOf('?') === -1 ? '?' : '&';
                      var urlArgs = delimiter + context.urlArgs;
                      if (val.value.indexOf('#') !== -1) {
                          val.value = val.value.replace('#', urlArgs + "#");
                      }
                      else {
                          val.value += urlArgs;
                      }
                  }
              }
          }
          return new URL(val, this.getIndex(), this.fileInfo(), true);
      };
      return URL;
  }(Node));
  URL.prototype.type = 'Url';
  function escapePath(path) {
      return path.replace(/[\(\)'"\s]/g, function (match) { return "\\" + match; });
  }

  var Media = /** @class */ (function (_super) {
      __extends(Media, _super);
      function Media(value, features, index, currentFileInfo, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          var selectors = (new Selector([], null, null, _this._index, _this._fileInfo)).createEmptySelectors();
          _this.features = new Value(features);
          _this.rules = [new Ruleset(selectors, value)];
          _this.rules[0].allowImports = true;
          _this.copyVisibilityInfo(visibilityInfo);
          _this.allowRoot = true;
          _this.setParent(selectors, _this);
          _this.setParent(_this.features, _this);
          _this.setParent(_this.rules, _this);
          return _this;
      }
      Media.prototype.isRulesetLike = function () {
          return true;
      };
      Media.prototype.accept = function (visitor) {
          if (this.features) {
              this.features = visitor.visit(this.features);
          }
          if (this.rules) {
              this.rules = visitor.visitArray(this.rules);
          }
      };
      Media.prototype.genCSS = function (context, output) {
          output.add('@media ', this._fileInfo, this._index);
          this.features.genCSS(context, output);
          this.outputRuleset(context, output, this.rules);
      };
      Media.prototype.eval = function (context) {
          if (!context.mediaBlocks) {
              context.mediaBlocks = [];
              context.mediaPath = [];
          }
          var media = new Media(null, [], this._index, this._fileInfo, this.visibilityInfo());
          if (this.debugInfo) {
              this.rules[0].debugInfo = this.debugInfo;
              media.debugInfo = this.debugInfo;
          }
          media.features = this.features.eval(context);
          context.mediaPath.push(media);
          context.mediaBlocks.push(media);
          this.rules[0].functionRegistry = context.frames[0].functionRegistry.inherit();
          context.frames.unshift(this.rules[0]);
          media.rules = [this.rules[0].eval(context)];
          context.frames.shift();
          context.mediaPath.pop();
          return context.mediaPath.length === 0 ? media.evalTop(context) :
              media.evalNested(context);
      };
      Media.prototype.evalTop = function (context) {
          var result = this;
          // Render all dependent Media blocks.
          if (context.mediaBlocks.length > 1) {
              var selectors = (new Selector([], null, null, this.getIndex(), this.fileInfo())).createEmptySelectors();
              result = new Ruleset(selectors, context.mediaBlocks);
              result.multiMedia = true;
              result.copyVisibilityInfo(this.visibilityInfo());
              this.setParent(result, this);
          }
          delete context.mediaBlocks;
          delete context.mediaPath;
          return result;
      };
      Media.prototype.evalNested = function (context) {
          var i;
          var value;
          var path = context.mediaPath.concat([this]);
          // Extract the media-query conditions separated with `,` (OR).
          for (i = 0; i < path.length; i++) {
              value = path[i].features instanceof Value ?
                  path[i].features.value : path[i].features;
              path[i] = Array.isArray(value) ? value : [value];
          }
          // Trace all permutations to generate the resulting media-query.
          //
          // (a, b and c) with nested (d, e) ->
          //    a and d
          //    a and e
          //    b and c and d
          //    b and c and e
          this.features = new Value(this.permute(path).map(function (path) {
              path = path.map(function (fragment) { return fragment.toCSS ? fragment : new Anonymous(fragment); });
              for (i = path.length - 1; i > 0; i--) {
                  path.splice(i, 0, new Anonymous('and'));
              }
              return new Expression(path);
          }));
          this.setParent(this.features, this);
          // Fake a tree-node that doesn't output anything.
          return new Ruleset([], []);
      };
      Media.prototype.permute = function (arr) {
          if (arr.length === 0) {
              return [];
          }
          else if (arr.length === 1) {
              return arr[0];
          }
          else {
              var result = [];
              var rest = this.permute(arr.slice(1));
              for (var i_1 = 0; i_1 < rest.length; i_1++) {
                  for (var j = 0; j < arr[0].length; j++) {
                      result.push([arr[0][j]].concat(rest[i_1]));
                  }
              }
              return result;
          }
      };
      Media.prototype.bubbleSelectors = function (selectors) {
          if (!selectors) {
              return;
          }
          this.rules = [new Ruleset(copyArray(selectors), [this.rules[0]])];
          this.setParent(this.rules, this);
      };
      return Media;
  }(AtRule));
  Media.prototype.type = 'Media';

  //
  // CSS @import node
  //
  // The general strategy here is that we don't want to wait
  // for the parsing to be completed, before we start importing
  // the file. That's because in the context of a browser,
  // most of the time will be spent waiting for the server to respond.
  //
  // On creation, we push the import path to our import queue, though
  // `import,push`, we also pass it a callback, which it'll call once
  // the file has been fetched, and parsed.
  //
  var Import = /** @class */ (function (_super) {
      __extends(Import, _super);
      function Import(path, features, options, index, currentFileInfo, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this.options = options;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.path = path;
          _this.features = features;
          _this.allowRoot = true;
          if (_this.options.less !== undefined || _this.options.inline) {
              _this.css = !_this.options.less || _this.options.inline;
          }
          else {
              var pathValue = _this.getPath();
              if (pathValue && /[#\.\&\?]css([\?;].*)?$/.test(pathValue)) {
                  _this.css = true;
              }
          }
          _this.copyVisibilityInfo(visibilityInfo);
          _this.setParent(_this.features, _this);
          _this.setParent(_this.path, _this);
          return _this;
      }
      Import.prototype.accept = function (visitor) {
          if (this.features) {
              this.features = visitor.visit(this.features);
          }
          this.path = visitor.visit(this.path);
          if (!this.options.isPlugin && !this.options.inline && this.root) {
              this.root = visitor.visit(this.root);
          }
      };
      Import.prototype.genCSS = function (context, output) {
          if (this.css && this.path._fileInfo.reference === undefined) {
              output.add('@import ', this._fileInfo, this._index);
              this.path.genCSS(context, output);
              if (this.features) {
                  output.add(' ');
                  this.features.genCSS(context, output);
              }
              output.add(';');
          }
      };
      Import.prototype.getPath = function () {
          return (this.path instanceof URL) ?
              this.path.value.value : this.path.value;
      };
      Import.prototype.isVariableImport = function () {
          var path = this.path;
          if (path instanceof URL) {
              path = path.value;
          }
          if (path instanceof Quoted) {
              return path.containsVariables();
          }
          return true;
      };
      Import.prototype.evalForImport = function (context) {
          var path = this.path;
          if (path instanceof URL) {
              path = path.value;
          }
          return new Import(path.eval(context), this.features, this.options, this._index, this._fileInfo, this.visibilityInfo());
      };
      Import.prototype.evalPath = function (context) {
          var path = this.path.eval(context);
          var fileInfo = this._fileInfo;
          if (!(path instanceof URL)) {
              // Add the rootpath if the URL requires a rewrite
              var pathValue = path.value;
              if (fileInfo &&
                  pathValue &&
                  context.pathRequiresRewrite(pathValue)) {
                  path.value = context.rewritePath(pathValue, fileInfo.rootpath);
              }
              else {
                  path.value = context.normalizePath(path.value);
              }
          }
          return path;
      };
      Import.prototype.eval = function (context) {
          var result = this.doEval(context);
          if (this.options.reference || this.blocksVisibility()) {
              if (result.length || result.length === 0) {
                  result.forEach(function (node) {
                      node.addVisibilityBlock();
                  });
              }
              else {
                  result.addVisibilityBlock();
              }
          }
          return result;
      };
      Import.prototype.doEval = function (context) {
          var ruleset;
          var registry;
          var features = this.features && this.features.eval(context);
          if (this.options.isPlugin) {
              if (this.root && this.root.eval) {
                  try {
                      this.root.eval(context);
                  }
                  catch (e) {
                      e.message = 'Plugin error during evaluation';
                      throw new LessError(e, this.root.imports, this.root.filename);
                  }
              }
              registry = context.frames[0] && context.frames[0].functionRegistry;
              if (registry && this.root && this.root.functions) {
                  registry.addMultiple(this.root.functions);
              }
              return [];
          }
          if (this.skip) {
              if (typeof this.skip === 'function') {
                  this.skip = this.skip();
              }
              if (this.skip) {
                  return [];
              }
          }
          if (this.options.inline) {
              var contents = new Anonymous(this.root, 0, {
                  filename: this.importedFilename,
                  reference: this.path._fileInfo && this.path._fileInfo.reference
              }, true, true);
              return this.features ? new Media([contents], this.features.value) : [contents];
          }
          else if (this.css) {
              var newImport = new Import(this.evalPath(context), features, this.options, this._index);
              if (!newImport.css && this.error) {
                  throw this.error;
              }
              return newImport;
          }
          else {
              ruleset = new Ruleset(null, copyArray(this.root.rules));
              ruleset.evalImports(context);
              return this.features ? new Media(ruleset.rules, this.features.value) : ruleset.rules;
          }
      };
      return Import;
  }(Node));
  Import.prototype.type = 'Import';

  var JsEvalNode = /** @class */ (function (_super) {
      __extends(JsEvalNode, _super);
      function JsEvalNode() {
          return _super !== null && _super.apply(this, arguments) || this;
      }
      JsEvalNode.prototype.evaluateJavaScript = function (expression, context) {
          var result;
          var that = this;
          var evalContext = {};
          if (!context.javascriptEnabled) {
              throw { message: 'Inline JavaScript is not enabled. Is it set in your options?',
                  filename: this.fileInfo().filename,
                  index: this.getIndex() };
          }
          expression = expression.replace(/@\{([\w-]+)\}/g, function (_, name) { return that.jsify(new Variable("@" + name, that.getIndex(), that.fileInfo()).eval(context)); });
          try {
              expression = new Function("return (" + expression + ")");
          }
          catch (e) {
              throw { message: "JavaScript evaluation error: " + e.message + " from `" + expression + "`",
                  filename: this.fileInfo().filename,
                  index: this.getIndex() };
          }
          var variables = context.frames[0].variables();
          for (var k in variables) {
              if (variables.hasOwnProperty(k)) {
                  /* jshint loopfunc:true */
                  evalContext[k.slice(1)] = {
                      value: variables[k].value,
                      toJS: function () {
                          return this.value.eval(context).toCSS();
                      }
                  };
              }
          }
          try {
              result = expression.call(evalContext);
          }
          catch (e) {
              throw { message: "JavaScript evaluation error: '" + e.name + ": " + e.message.replace(/["]/g, '\'') + "'",
                  filename: this.fileInfo().filename,
                  index: this.getIndex() };
          }
          return result;
      };
      JsEvalNode.prototype.jsify = function (obj) {
          if (Array.isArray(obj.value) && (obj.value.length > 1)) {
              return "[" + obj.value.map(function (v) { return v.toCSS(); }).join(', ') + "]";
          }
          else {
              return obj.toCSS();
          }
      };
      return JsEvalNode;
  }(Node));

  var JavaScript = /** @class */ (function (_super) {
      __extends(JavaScript, _super);
      function JavaScript(string, escaped, index, currentFileInfo) {
          var _this = _super.call(this) || this;
          _this.escaped = escaped;
          _this.expression = string;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          return _this;
      }
      JavaScript.prototype.eval = function (context) {
          var result = this.evaluateJavaScript(this.expression, context);
          var type = typeof result;
          if (type === 'number' && !isNaN(result)) {
              return new Dimension(result);
          }
          else if (type === 'string') {
              return new Quoted("\"" + result + "\"", result, this.escaped, this._index);
          }
          else if (Array.isArray(result)) {
              return new Anonymous(result.join(', '));
          }
          else {
              return new Anonymous(result);
          }
      };
      return JavaScript;
  }(JsEvalNode));
  JavaScript.prototype.type = 'JavaScript';

  var Assignment = /** @class */ (function (_super) {
      __extends(Assignment, _super);
      function Assignment(key, val) {
          var _this = _super.call(this) || this;
          _this.key = key;
          _this.value = val;
          return _this;
      }
      Assignment.prototype.accept = function (visitor) {
          this.value = visitor.visit(this.value);
      };
      Assignment.prototype.eval = function (context) {
          if (this.value.eval) {
              return new Assignment(this.key, this.value.eval(context));
          }
          return this;
      };
      Assignment.prototype.genCSS = function (context, output) {
          output.add(this.key + "=");
          if (this.value.genCSS) {
              this.value.genCSS(context, output);
          }
          else {
              output.add(this.value);
          }
      };
      return Assignment;
  }(Node));
  Assignment.prototype.type = 'Assignment';

  var Condition = /** @class */ (function (_super) {
      __extends(Condition, _super);
      function Condition(op, l, r, i, negate) {
          var _this = _super.call(this) || this;
          _this.op = op.trim();
          _this.lvalue = l;
          _this.rvalue = r;
          _this._index = i;
          _this.negate = negate;
          return _this;
      }
      Condition.prototype.accept = function (visitor) {
          this.lvalue = visitor.visit(this.lvalue);
          this.rvalue = visitor.visit(this.rvalue);
      };
      Condition.prototype.eval = function (context) {
          var result = (function (op, a, b) {
              switch (op) {
                  case 'and': return a && b;
                  case 'or': return a || b;
                  default:
                      switch (Node.compare(a, b)) {
                          case -1:
                              return op === '<' || op === '=<' || op === '<=';
                          case 0:
                              return op === '=' || op === '>=' || op === '=<' || op === '<=';
                          case 1:
                              return op === '>' || op === '>=';
                          default:
                              return false;
                      }
              }
          })(this.op, this.lvalue.eval(context), this.rvalue.eval(context));
          return this.negate ? !result : result;
      };
      return Condition;
  }(Node));
  Condition.prototype.type = 'Condition';

  var UnicodeDescriptor = /** @class */ (function (_super) {
      __extends(UnicodeDescriptor, _super);
      function UnicodeDescriptor(value) {
          var _this = _super.call(this) || this;
          _this.value = value;
          return _this;
      }
      return UnicodeDescriptor;
  }(Node));
  UnicodeDescriptor.prototype.type = 'UnicodeDescriptor';

  var Negative = /** @class */ (function (_super) {
      __extends(Negative, _super);
      function Negative(node) {
          var _this = _super.call(this) || this;
          _this.value = node;
          return _this;
      }
      Negative.prototype.genCSS = function (context, output) {
          output.add('-');
          this.value.genCSS(context, output);
      };
      Negative.prototype.eval = function (context) {
          if (context.isMathOn()) {
              return (new Operation('*', [new Dimension(-1), this.value])).eval(context);
          }
          return new Negative(this.value.eval(context));
      };
      return Negative;
  }(Node));
  Negative.prototype.type = 'Negative';

  var Extend = /** @class */ (function (_super) {
      __extends(Extend, _super);
      function Extend(selector, option, index, currentFileInfo, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this.selector = selector;
          _this.option = option;
          _this.object_id = Extend.next_id++;
          _this.parent_ids = [_this.object_id];
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.copyVisibilityInfo(visibilityInfo);
          _this.allowRoot = true;
          switch (option) {
              case 'all':
                  _this.allowBefore = true;
                  _this.allowAfter = true;
                  break;
              default:
                  _this.allowBefore = false;
                  _this.allowAfter = false;
                  break;
          }
          _this.setParent(_this.selector, _this);
          return _this;
      }
      Extend.prototype.accept = function (visitor) {
          this.selector = visitor.visit(this.selector);
      };
      Extend.prototype.eval = function (context) {
          return new Extend(this.selector.eval(context), this.option, this.getIndex(), this.fileInfo(), this.visibilityInfo());
      };
      Extend.prototype.clone = function (context) {
          return new Extend(this.selector, this.option, this.getIndex(), this.fileInfo(), this.visibilityInfo());
      };
      // it concatenates (joins) all selectors in selector array
      Extend.prototype.findSelfSelectors = function (selectors) {
          var selfElements = [];
          var i;
          var selectorElements;
          for (i = 0; i < selectors.length; i++) {
              selectorElements = selectors[i].elements;
              // duplicate the logic in genCSS function inside the selector node.
              // future TODO - move both logics into the selector joiner visitor
              if (i > 0 && selectorElements.length && selectorElements[0].combinator.value === '') {
                  selectorElements[0].combinator.value = ' ';
              }
              selfElements = selfElements.concat(selectors[i].elements);
          }
          this.selfSelectors = [new Selector(selfElements)];
          this.selfSelectors[0].copyVisibilityInfo(this.visibilityInfo());
      };
      return Extend;
  }(Node));
  Extend.next_id = 0;
  Extend.prototype.type = 'Extend';

  var VariableCall = /** @class */ (function (_super) {
      __extends(VariableCall, _super);
      function VariableCall(variable, index, currentFileInfo) {
          var _this = _super.call(this) || this;
          _this.variable = variable;
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.allowRoot = true;
          return _this;
      }
      VariableCall.prototype.eval = function (context) {
          var rules;
          var detachedRuleset = new Variable(this.variable, this.getIndex(), this.fileInfo()).eval(context);
          var error = new LessError({ message: "Could not evaluate variable call " + this.variable });
          if (!detachedRuleset.ruleset) {
              if (detachedRuleset.rules) {
                  rules = detachedRuleset;
              }
              else if (Array.isArray(detachedRuleset)) {
                  rules = new Ruleset('', detachedRuleset);
              }
              else if (Array.isArray(detachedRuleset.value)) {
                  rules = new Ruleset('', detachedRuleset.value);
              }
              else {
                  throw error;
              }
              detachedRuleset = new DetachedRuleset(rules);
          }
          if (detachedRuleset.ruleset) {
              return detachedRuleset.callEval(context);
          }
          throw error;
      };
      return VariableCall;
  }(Node));
  VariableCall.prototype.type = 'VariableCall';

  var NamespaceValue = /** @class */ (function (_super) {
      __extends(NamespaceValue, _super);
      function NamespaceValue(ruleCall, lookups, index, fileInfo) {
          var _this = _super.call(this) || this;
          _this.value = ruleCall;
          _this.lookups = lookups;
          _this._index = index;
          _this._fileInfo = fileInfo;
          return _this;
      }
      NamespaceValue.prototype.eval = function (context) {
          var i;
          var name;
          var rules = this.value.eval(context);
          for (i = 0; i < this.lookups.length; i++) {
              name = this.lookups[i];
              /**
               * Eval'd DRs return rulesets.
               * Eval'd mixins return rules, so let's make a ruleset if we need it.
               * We need to do this because of late parsing of values
               */
              if (Array.isArray(rules)) {
                  rules = new Ruleset([new Selector()], rules);
              }
              if (name === '') {
                  rules = rules.lastDeclaration();
              }
              else if (name.charAt(0) === '@') {
                  if (name.charAt(1) === '@') {
                      name = "@" + new Variable(name.substr(1)).eval(context).value;
                  }
                  if (rules.variables) {
                      rules = rules.variable(name);
                  }
                  if (!rules) {
                      throw { type: 'Name',
                          message: "variable " + name + " not found",
                          filename: this.fileInfo().filename,
                          index: this.getIndex() };
                  }
              }
              else {
                  if (name.substring(0, 2) === '$@') {
                      name = "$" + new Variable(name.substr(1)).eval(context).value;
                  }
                  else {
                      name = name.charAt(0) === '$' ? name : "$" + name;
                  }
                  if (rules.properties) {
                      rules = rules.property(name);
                  }
                  if (!rules) {
                      throw { type: 'Name',
                          message: "property \"" + name.substr(1) + "\" not found",
                          filename: this.fileInfo().filename,
                          index: this.getIndex() };
                  }
                  // Properties are an array of values, since a ruleset can have multiple props.
                  // We pick the last one (the "cascaded" value)
                  rules = rules[rules.length - 1];
              }
              if (rules.value) {
                  rules = rules.eval(context).value;
              }
              if (rules.ruleset) {
                  rules = rules.ruleset.eval(context);
              }
          }
          return rules;
      };
      return NamespaceValue;
  }(Node));
  NamespaceValue.prototype.type = 'NamespaceValue';

  var Definition = /** @class */ (function (_super) {
      __extends(Definition, _super);
      function Definition(name, params, rules, condition, variadic, frames, visibilityInfo) {
          var _this = _super.call(this) || this;
          _this.name = name || 'anonymous mixin';
          _this.selectors = [new Selector([new Element(null, name, false, _this._index, _this._fileInfo)])];
          _this.params = params;
          _this.condition = condition;
          _this.variadic = variadic;
          _this.arity = params.length;
          _this.rules = rules;
          _this._lookups = {};
          var optionalParameters = [];
          _this.required = params.reduce(function (count, p) {
              if (!p.name || (p.name && !p.value)) {
                  return count + 1;
              }
              else {
                  optionalParameters.push(p.name);
                  return count;
              }
          }, 0);
          _this.optionalParameters = optionalParameters;
          _this.frames = frames;
          _this.copyVisibilityInfo(visibilityInfo);
          _this.allowRoot = true;
          return _this;
      }
      Definition.prototype.accept = function (visitor) {
          if (this.params && this.params.length) {
              this.params = visitor.visitArray(this.params);
          }
          this.rules = visitor.visitArray(this.rules);
          if (this.condition) {
              this.condition = visitor.visit(this.condition);
          }
      };
      Definition.prototype.evalParams = function (context, mixinEnv, args, evaldArguments) {
          /* jshint boss:true */
          var frame = new Ruleset(null, null);
          var varargs;
          var arg;
          var params = copyArray(this.params);
          var i;
          var j;
          var val;
          var name;
          var isNamedFound;
          var argIndex;
          var argsLength = 0;
          if (mixinEnv.frames && mixinEnv.frames[0] && mixinEnv.frames[0].functionRegistry) {
              frame.functionRegistry = mixinEnv.frames[0].functionRegistry.inherit();
          }
          mixinEnv = new contexts.Eval(mixinEnv, [frame].concat(mixinEnv.frames));
          if (args) {
              args = copyArray(args);
              argsLength = args.length;
              for (i = 0; i < argsLength; i++) {
                  arg = args[i];
                  if (name = (arg && arg.name)) {
                      isNamedFound = false;
                      for (j = 0; j < params.length; j++) {
                          if (!evaldArguments[j] && name === params[j].name) {
                              evaldArguments[j] = arg.value.eval(context);
                              frame.prependRule(new Declaration(name, arg.value.eval(context)));
                              isNamedFound = true;
                              break;
                          }
                      }
                      if (isNamedFound) {
                          args.splice(i, 1);
                          i--;
                          continue;
                      }
                      else {
                          throw { type: 'Runtime', message: "Named argument for " + this.name + " " + args[i].name + " not found" };
                      }
                  }
              }
          }
          argIndex = 0;
          for (i = 0; i < params.length; i++) {
              if (evaldArguments[i]) {
                  continue;
              }
              arg = args && args[argIndex];
              if (name = params[i].name) {
                  if (params[i].variadic) {
                      varargs = [];
                      for (j = argIndex; j < argsLength; j++) {
                          varargs.push(args[j].value.eval(context));
                      }
                      frame.prependRule(new Declaration(name, new Expression(varargs).eval(context)));
                  }
                  else {
                      val = arg && arg.value;
                      if (val) {
                          // This was a mixin call, pass in a detached ruleset of it's eval'd rules
                          if (Array.isArray(val)) {
                              val = new DetachedRuleset(new Ruleset('', val));
                          }
                          else {
                              val = val.eval(context);
                          }
                      }
                      else if (params[i].value) {
                          val = params[i].value.eval(mixinEnv);
                          frame.resetCache();
                      }
                      else {
                          throw { type: 'Runtime', message: "wrong number of arguments for " + this.name + " (" + argsLength + " for " + this.arity + ")" };
                      }
                      frame.prependRule(new Declaration(name, val));
                      evaldArguments[i] = val;
                  }
              }
              if (params[i].variadic && args) {
                  for (j = argIndex; j < argsLength; j++) {
                      evaldArguments[j] = args[j].value.eval(context);
                  }
              }
              argIndex++;
          }
          return frame;
      };
      Definition.prototype.makeImportant = function () {
          var rules = !this.rules ? this.rules : this.rules.map(function (r) {
              if (r.makeImportant) {
                  return r.makeImportant(true);
              }
              else {
                  return r;
              }
          });
          var result = new Definition(this.name, this.params, rules, this.condition, this.variadic, this.frames);
          return result;
      };
      Definition.prototype.eval = function (context) {
          return new Definition(this.name, this.params, this.rules, this.condition, this.variadic, this.frames || copyArray(context.frames));
      };
      Definition.prototype.evalCall = function (context, args, important) {
          var _arguments = [];
          var mixinFrames = this.frames ? this.frames.concat(context.frames) : context.frames;
          var frame = this.evalParams(context, new contexts.Eval(context, mixinFrames), args, _arguments);
          var rules;
          var ruleset;
          frame.prependRule(new Declaration('@arguments', new Expression(_arguments).eval(context)));
          rules = copyArray(this.rules);
          ruleset = new Ruleset(null, rules);
          ruleset.originalRuleset = this;
          ruleset = ruleset.eval(new contexts.Eval(context, [this, frame].concat(mixinFrames)));
          if (important) {
              ruleset = ruleset.makeImportant();
          }
          return ruleset;
      };
      Definition.prototype.matchCondition = function (args, context) {
          if (this.condition && !this.condition.eval(new contexts.Eval(context, [this.evalParams(context, /* the parameter variables */ new contexts.Eval(context, this.frames ? this.frames.concat(context.frames) : context.frames), args, [])]
              .concat(this.frames || []) // the parent namespace/mixin frames
              .concat(context.frames)))) { // the current environment frames
              return false;
          }
          return true;
      };
      Definition.prototype.matchArgs = function (args, context) {
          var allArgsCnt = (args && args.length) || 0;
          var len;
          var optionalParameters = this.optionalParameters;
          var requiredArgsCnt = !args ? 0 : args.reduce(function (count, p) {
              if (optionalParameters.indexOf(p.name) < 0) {
                  return count + 1;
              }
              else {
                  return count;
              }
          }, 0);
          if (!this.variadic) {
              if (requiredArgsCnt < this.required) {
                  return false;
              }
              if (allArgsCnt > this.params.length) {
                  return false;
              }
          }
          else {
              if (requiredArgsCnt < (this.required - 1)) {
                  return false;
              }
          }
          // check patterns
          len = Math.min(requiredArgsCnt, this.arity);
          for (var i_1 = 0; i_1 < len; i_1++) {
              if (!this.params[i_1].name && !this.params[i_1].variadic) {
                  if (args[i_1].value.eval(context).toCSS() != this.params[i_1].value.eval(context).toCSS()) {
                      return false;
                  }
              }
          }
          return true;
      };
      return Definition;
  }(Ruleset));
  Definition.prototype.type = 'MixinDefinition';
  Definition.prototype.evalFirst = true;

  var MixinCall = /** @class */ (function (_super) {
      __extends(MixinCall, _super);
      function MixinCall(elements, args, index, currentFileInfo, important) {
          var _this = _super.call(this) || this;
          _this.selector = new Selector(elements);
          _this.arguments = args || [];
          _this._index = index;
          _this._fileInfo = currentFileInfo;
          _this.important = important;
          _this.allowRoot = true;
          _this.setParent(_this.selector, _this);
          return _this;
      }
      MixinCall.prototype.accept = function (visitor) {
          if (this.selector) {
              this.selector = visitor.visit(this.selector);
          }
          if (this.arguments.length) {
              this.arguments = visitor.visitArray(this.arguments);
          }
      };
      MixinCall.prototype.eval = function (context) {
          var mixins;
          var mixin;
          var mixinPath;
          var args = [];
          var arg;
          var argValue;
          var rules = [];
          var match = false;
          var i;
          var m;
          var f;
          var isRecursive;
          var isOneFound;
          var candidates = [];
          var candidate;
          var conditionResult = [];
          var defaultResult;
          var defFalseEitherCase = -1;
          var defNone = 0;
          var defTrue = 1;
          var defFalse = 2;
          var count;
          var originalRuleset;
          var noArgumentsFilter;
          this.selector = this.selector.eval(context);
          function calcDefGroup(mixin, mixinPath) {
              var f;
              var p;
              var namespace;
              for (f = 0; f < 2; f++) {
                  conditionResult[f] = true;
                  defaultFunc.value(f);
                  for (p = 0; p < mixinPath.length && conditionResult[f]; p++) {
                      namespace = mixinPath[p];
                      if (namespace.matchCondition) {
                          conditionResult[f] = conditionResult[f] && namespace.matchCondition(null, context);
                      }
                  }
                  if (mixin.matchCondition) {
                      conditionResult[f] = conditionResult[f] && mixin.matchCondition(args, context);
                  }
              }
              if (conditionResult[0] || conditionResult[1]) {
                  if (conditionResult[0] != conditionResult[1]) {
                      return conditionResult[1] ?
                          defTrue : defFalse;
                  }
                  return defNone;
              }
              return defFalseEitherCase;
          }
          for (i = 0; i < this.arguments.length; i++) {
              arg = this.arguments[i];
              argValue = arg.value.eval(context);
              if (arg.expand && Array.isArray(argValue.value)) {
                  argValue = argValue.value;
                  for (m = 0; m < argValue.length; m++) {
                      args.push({ value: argValue[m] });
                  }
              }
              else {
                  args.push({ name: arg.name, value: argValue });
              }
          }
          noArgumentsFilter = function (rule) { return rule.matchArgs(null, context); };
          for (i = 0; i < context.frames.length; i++) {
              if ((mixins = context.frames[i].find(this.selector, null, noArgumentsFilter)).length > 0) {
                  isOneFound = true;
                  // To make `default()` function independent of definition order we have two "subpasses" here.
                  // At first we evaluate each guard *twice* (with `default() == true` and `default() == false`),
                  // and build candidate list with corresponding flags. Then, when we know all possible matches,
                  // we make a final decision.
                  for (m = 0; m < mixins.length; m++) {
                      mixin = mixins[m].rule;
                      mixinPath = mixins[m].path;
                      isRecursive = false;
                      for (f = 0; f < context.frames.length; f++) {
                          if ((!(mixin instanceof Definition)) && mixin === (context.frames[f].originalRuleset || context.frames[f])) {
                              isRecursive = true;
                              break;
                          }
                      }
                      if (isRecursive) {
                          continue;
                      }
                      if (mixin.matchArgs(args, context)) {
                          candidate = { mixin: mixin, group: calcDefGroup(mixin, mixinPath) };
                          if (candidate.group !== defFalseEitherCase) {
                              candidates.push(candidate);
                          }
                          match = true;
                      }
                  }
                  defaultFunc.reset();
                  count = [0, 0, 0];
                  for (m = 0; m < candidates.length; m++) {
                      count[candidates[m].group]++;
                  }
                  if (count[defNone] > 0) {
                      defaultResult = defFalse;
                  }
                  else {
                      defaultResult = defTrue;
                      if ((count[defTrue] + count[defFalse]) > 1) {
                          throw { type: 'Runtime',
                              message: "Ambiguous use of `default()` found when matching for `" + this.format(args) + "`",
                              index: this.getIndex(), filename: this.fileInfo().filename };
                      }
                  }
                  for (m = 0; m < candidates.length; m++) {
                      candidate = candidates[m].group;
                      if ((candidate === defNone) || (candidate === defaultResult)) {
                          try {
                              mixin = candidates[m].mixin;
                              if (!(mixin instanceof Definition)) {
                                  originalRuleset = mixin.originalRuleset || mixin;
                                  mixin = new Definition('', [], mixin.rules, null, false, null, originalRuleset.visibilityInfo());
                                  mixin.originalRuleset = originalRuleset;
                              }
                              var newRules = mixin.evalCall(context, args, this.important).rules;
                              this._setVisibilityToReplacement(newRules);
                              Array.prototype.push.apply(rules, newRules);
                          }
                          catch (e) {
                              throw { message: e.message, index: this.getIndex(), filename: this.fileInfo().filename, stack: e.stack };
                          }
                      }
                  }
                  if (match) {
                      return rules;
                  }
              }
          }
          if (isOneFound) {
              throw { type: 'Runtime',
                  message: "No matching definition was found for `" + this.format(args) + "`",
                  index: this.getIndex(), filename: this.fileInfo().filename };
          }
          else {
              throw { type: 'Name',
                  message: this.selector.toCSS().trim() + " is undefined",
                  index: this.getIndex(), filename: this.fileInfo().filename };
          }
      };
      MixinCall.prototype._setVisibilityToReplacement = function (replacement) {
          var i;
          var rule;
          if (this.blocksVisibility()) {
              for (i = 0; i < replacement.length; i++) {
                  rule = replacement[i];
                  rule.addVisibilityBlock();
              }
          }
      };
      MixinCall.prototype.format = function (args) {
          return this.selector.toCSS().trim() + "(" + (args ? args.map(function (a) {
              var argValue = '';
              if (a.name) {
                  argValue += a.name + ":";
              }
              if (a.value.toCSS) {
                  argValue += a.value.toCSS();
              }
              else {
                  argValue += '???';
              }
              return argValue;
          }).join(', ') : '') + ")";
      };
      return MixinCall;
  }(Node));
  MixinCall.prototype.type = 'MixinCall';

  var tree = {
      Node: Node, Color: Color, AtRule: AtRule, DetachedRuleset: DetachedRuleset, Operation: Operation,
      Dimension: Dimension, Unit: Unit, Keyword: Keyword, Variable: Variable, Property: Property,
      Ruleset: Ruleset, Element: Element, Attribute: Attribute, Combinator: Combinator, Selector: Selector,
      Quoted: Quoted, Expression: Expression, Declaration: Declaration, Call: Call, URL: URL, Import: Import,
      Comment: Comment, Anonymous: Anonymous, Value: Value, JavaScript: JavaScript, Assignment: Assignment,
      Condition: Condition, Paren: Paren, Media: Media, UnicodeDescriptor: UnicodeDescriptor, Negative: Negative,
      Extend: Extend, VariableCall: VariableCall, NamespaceValue: NamespaceValue,
      mixin: {
          Call: MixinCall,
          Definition: Definition
      }
  };

  var logger = {
      error: function (msg) {
          this._fireEvent('error', msg);
      },
      warn: function (msg) {
          this._fireEvent('warn', msg);
      },
      info: function (msg) {
          this._fireEvent('info', msg);
      },
      debug: function (msg) {
          this._fireEvent('debug', msg);
      },
      addListener: function (listener) {
          this._listeners.push(listener);
      },
      removeListener: function (listener) {
          for (var i_1 = 0; i_1 < this._listeners.length; i_1++) {
              if (this._listeners[i_1] === listener) {
                  this._listeners.splice(i_1, 1);
                  return;
              }
          }
      },
      _fireEvent: function (type, msg) {
          for (var i_2 = 0; i_2 < this._listeners.length; i_2++) {
              var logFunction = this._listeners[i_2][type];
              if (logFunction) {
                  logFunction(msg);
              }
          }
      },
      _listeners: []
  };

  /**
   * @todo Document why this abstraction exists, and the relationship between
   *       environment, file managers, and plugin manager
   */
  var environment = /** @class */ (function () {
      function environment(externalEnvironment, fileManagers) {
          this.fileManagers = fileManagers || [];
          externalEnvironment = externalEnvironment || {};
          var optionalFunctions = ['encodeBase64', 'mimeLookup', 'charsetLookup', 'getSourceMapGenerator'];
          var requiredFunctions = [];
          var functions = requiredFunctions.concat(optionalFunctions);
          for (var i_1 = 0; i_1 < functions.length; i_1++) {
              var propName = functions[i_1];
              var environmentFunc = externalEnvironment[propName];
              if (environmentFunc) {
                  this[propName] = environmentFunc.bind(externalEnvironment);
              }
              else if (i_1 < requiredFunctions.length) {
                  this.warn("missing required function in environment - " + propName);
              }
          }
      }
      environment.prototype.getFileManager = function (filename, currentDirectory, options, environment, isSync) {
          if (!filename) {
              logger.warn('getFileManager called with no filename.. Please report this issue. continuing.');
          }
          if (currentDirectory == null) {
              logger.warn('getFileManager called with null directory.. Please report this issue. continuing.');
          }
          var fileManagers = this.fileManagers;
          if (options.pluginManager) {
              fileManagers = [].concat(fileManagers).concat(options.pluginManager.getFileManagers());
          }
          for (var i_2 = fileManagers.length - 1; i_2 >= 0; i_2--) {
              var fileManager = fileManagers[i_2];
              if (fileManager[isSync ? 'supportsSync' : 'supports'](filename, currentDirectory, options, environment)) {
                  return fileManager;
              }
          }
          return null;
      };
      environment.prototype.addFileManager = function (fileManager) {
          this.fileManagers.push(fileManager);
      };
      environment.prototype.clearFileManagers = function () {
          this.fileManagers = [];
      };
      return environment;
  }());

  var AbstractFileManager = /** @class */ (function () {
      function AbstractFileManager() {
      }
      AbstractFileManager.prototype.getPath = function (filename) {
          var j = filename.lastIndexOf('?');
          if (j > 0) {
              filename = filename.slice(0, j);
          }
          j = filename.lastIndexOf('/');
          if (j < 0) {
              j = filename.lastIndexOf('\\');
          }
          if (j < 0) {
              return '';
          }
          return filename.slice(0, j + 1);
      };
      AbstractFileManager.prototype.tryAppendExtension = function (path, ext) {
          return /(\.[a-z]*$)|([\?;].*)$/.test(path) ? path : path + ext;
      };
      AbstractFileManager.prototype.tryAppendLessExtension = function (path) {
          return this.tryAppendExtension(path, '.less');
      };
      AbstractFileManager.prototype.supportsSync = function () { return false; };
      AbstractFileManager.prototype.alwaysMakePathsAbsolute = function () { return false; };
      AbstractFileManager.prototype.isPathAbsolute = function (filename) {
          return (/^(?:[a-z-]+:|\/|\\|#)/i).test(filename);
      };
      // TODO: pull out / replace?
      AbstractFileManager.prototype.join = function (basePath, laterPath) {
          if (!basePath) {
              return laterPath;
          }
          return basePath + laterPath;
      };
      AbstractFileManager.prototype.pathDiff = function (url, baseUrl) {
          // diff between two paths to create a relative path
          var urlParts = this.extractUrlParts(url);
          var baseUrlParts = this.extractUrlParts(baseUrl);
          var i;
          var max;
          var urlDirectories;
          var baseUrlDirectories;
          var diff = '';
          if (urlParts.hostPart !== baseUrlParts.hostPart) {
              return '';
          }
          max = Math.max(baseUrlParts.directories.length, urlParts.directories.length);
          for (i = 0; i < max; i++) {
              if (baseUrlParts.directories[i] !== urlParts.directories[i]) {
                  break;
              }
          }
          baseUrlDirectories = baseUrlParts.directories.slice(i);
          urlDirectories = urlParts.directories.slice(i);
          for (i = 0; i < baseUrlDirectories.length - 1; i++) {
              diff += '../';
          }
          for (i = 0; i < urlDirectories.length - 1; i++) {
              diff += urlDirectories[i] + "/";
          }
          return diff;
      };
      // helper function, not part of API
      AbstractFileManager.prototype.extractUrlParts = function (url, baseUrl) {
          // urlParts[1] = protocol://hostname/ OR /
          // urlParts[2] = / if path relative to host base
          // urlParts[3] = directories
          // urlParts[4] = filename
          // urlParts[5] = parameters
          var urlPartsRegex = /^((?:[a-z-]+:)?\/{2}(?:[^\/\?#]*\/)|([\/\\]))?((?:[^\/\\\?#]*[\/\\])*)([^\/\\\?#]*)([#\?].*)?$/i;
          var urlParts = url.match(urlPartsRegex);
          var returner = {};
          var rawDirectories = [];
          var directories = [];
          var i;
          var baseUrlParts;
          if (!urlParts) {
              throw new Error("Could not parse sheet href - '" + url + "'");
          }
          // Stylesheets in IE don't always return the full path
          if (baseUrl && (!urlParts[1] || urlParts[2])) {
              baseUrlParts = baseUrl.match(urlPartsRegex);
              if (!baseUrlParts) {
                  throw new Error("Could not parse page url - '" + baseUrl + "'");
              }
              urlParts[1] = urlParts[1] || baseUrlParts[1] || '';
              if (!urlParts[2]) {
                  urlParts[3] = baseUrlParts[3] + urlParts[3];
              }
          }
          if (urlParts[3]) {
              rawDirectories = urlParts[3].replace(/\\/g, '/').split('/');
              // collapse '..' and skip '.'
              for (i = 0; i < rawDirectories.length; i++) {
                  if (rawDirectories[i] === '..') {
                      directories.pop();
                  }
                  else if (rawDirectories[i] !== '.') {
                      directories.push(rawDirectories[i]);
                  }
              }
          }
          returner.hostPart = urlParts[1];
          returner.directories = directories;
          returner.rawPath = (urlParts[1] || '') + rawDirectories.join('/');
          returner.path = (urlParts[1] || '') + directories.join('/');
          returner.filename = urlParts[4];
          returner.fileUrl = returner.path + (urlParts[4] || '');
          returner.url = returner.fileUrl + (urlParts[5] || '');
          return returner;
      };
      return AbstractFileManager;
  }());

  var AbstractPluginLoader = /** @class */ (function () {
      function AbstractPluginLoader() {
          // Implemented by Node.js plugin loader
          this.require = function () { return null; };
      }
      AbstractPluginLoader.prototype.evalPlugin = function (contents, context, imports, pluginOptions, fileInfo) {
          var loader;
          var registry;
          var pluginObj;
          var localModule;
          var pluginManager;
          var filename;
          var result;
          pluginManager = context.pluginManager;
          if (fileInfo) {
              if (typeof fileInfo === 'string') {
                  filename = fileInfo;
              }
              else {
                  filename = fileInfo.filename;
              }
          }
          var shortname = (new this.less.FileManager()).extractUrlParts(filename).filename;
          if (filename) {
              pluginObj = pluginManager.get(filename);
              if (pluginObj) {
                  result = this.trySetOptions(pluginObj, filename, shortname, pluginOptions);
                  if (result) {
                      return result;
                  }
                  try {
                      if (pluginObj.use) {
                          pluginObj.use.call(this.context, pluginObj);
                      }
                  }
                  catch (e) {
                      e.message = e.message || 'Error during @plugin call';
                      return new LessError(e, imports, filename);
                  }
                  return pluginObj;
              }
          }
          localModule = {
              exports: {},
              pluginManager: pluginManager,
              fileInfo: fileInfo
          };
          registry = functionRegistry.create();
          var registerPlugin = function (obj) {
              pluginObj = obj;
          };
          try {
              loader = new Function('module', 'require', 'registerPlugin', 'functions', 'tree', 'less', 'fileInfo', contents);
              loader(localModule, this.require(filename), registerPlugin, registry, this.less.tree, this.less, fileInfo);
          }
          catch (e) {
              return new LessError(e, imports, filename);
          }
          if (!pluginObj) {
              pluginObj = localModule.exports;
          }
          pluginObj = this.validatePlugin(pluginObj, filename, shortname);
          if (pluginObj instanceof LessError) {
              return pluginObj;
          }
          if (pluginObj) {
              pluginObj.imports = imports;
              pluginObj.filename = filename;
              // For < 3.x (or unspecified minVersion) - setOptions() before install()
              if (!pluginObj.minVersion || this.compareVersion('3.0.0', pluginObj.minVersion) < 0) {
                  result = this.trySetOptions(pluginObj, filename, shortname, pluginOptions);
                  if (result) {
                      return result;
                  }
              }
              // Run on first load
              pluginManager.addPlugin(pluginObj, fileInfo.filename, registry);
              pluginObj.functions = registry.getLocalFunctions();
              // Need to call setOptions again because the pluginObj might have functions
              result = this.trySetOptions(pluginObj, filename, shortname, pluginOptions);
              if (result) {
                  return result;
              }
              // Run every @plugin call
              try {
                  if (pluginObj.use) {
                      pluginObj.use.call(this.context, pluginObj);
                  }
              }
              catch (e) {
                  e.message = e.message || 'Error during @plugin call';
                  return new LessError(e, imports, filename);
              }
          }
          else {
              return new LessError({ message: 'Not a valid plugin' }, imports, filename);
          }
          return pluginObj;
      };
      AbstractPluginLoader.prototype.trySetOptions = function (plugin, filename, name, options) {
          if (options && !plugin.setOptions) {
              return new LessError({
                  message: "Options have been provided but the plugin " + name + " does not support any options."
              });
          }
          try {
              plugin.setOptions && plugin.setOptions(options);
          }
          catch (e) {
              return new LessError(e);
          }
      };
      AbstractPluginLoader.prototype.validatePlugin = function (plugin, filename, name) {
          if (plugin) {
              // support plugins being a function
              // so that the plugin can be more usable programmatically
              if (typeof plugin === 'function') {
                  plugin = new plugin();
              }
              if (plugin.minVersion) {
                  if (this.compareVersion(plugin.minVersion, this.less.version) < 0) {
                      return new LessError({
                          message: "Plugin " + name + " requires version " + this.versionToString(plugin.minVersion)
                      });
                  }
              }
              return plugin;
          }
          return null;
      };
      AbstractPluginLoader.prototype.compareVersion = function (aVersion, bVersion) {
          if (typeof aVersion === 'string') {
              aVersion = aVersion.match(/^(\d+)\.?(\d+)?\.?(\d+)?/);
              aVersion.shift();
          }
          for (var i_1 = 0; i_1 < aVersion.length; i_1++) {
              if (aVersion[i_1] !== bVersion[i_1]) {
                  return parseInt(aVersion[i_1]) > parseInt(bVersion[i_1]) ? -1 : 1;
              }
          }
          return 0;
      };
      AbstractPluginLoader.prototype.versionToString = function (version) {
          var versionString = '';
          for (var i_2 = 0; i_2 < version.length; i_2++) {
              versionString += (versionString ? '.' : '') + version[i_2];
          }
          return versionString;
      };
      AbstractPluginLoader.prototype.printUsage = function (plugins) {
          for (var i_3 = 0; i_3 < plugins.length; i_3++) {
              var plugin = plugins[i_3];
              if (plugin.printUsage) {
                  plugin.printUsage();
              }
          }
      };
      return AbstractPluginLoader;
  }());

  var _visitArgs = { visitDeeper: true };
  var _hasIndexed = false;
  function _noop(node) {
      return node;
  }
  function indexNodeTypes(parent, ticker) {
      // add .typeIndex to tree node types for lookup table
      var key;
      var child;
      for (key in parent) {
          /* eslint guard-for-in: 0 */
          child = parent[key];
          switch (typeof child) {
              case 'function':
                  // ignore bound functions directly on tree which do not have a prototype
                  // or aren't nodes
                  if (child.prototype && child.prototype.type) {
                      child.prototype.typeIndex = ticker++;
                  }
                  break;
              case 'object':
                  ticker = indexNodeTypes(child, ticker);
                  break;
          }
      }
      return ticker;
  }
  var Visitor = /** @class */ (function () {
      function Visitor(implementation) {
          this._implementation = implementation;
          this._visitInCache = {};
          this._visitOutCache = {};
          if (!_hasIndexed) {
              indexNodeTypes(tree, 1);
              _hasIndexed = true;
          }
      }
      Visitor.prototype.visit = function (node) {
          if (!node) {
              return node;
          }
          var nodeTypeIndex = node.typeIndex;
          if (!nodeTypeIndex) {
              // MixinCall args aren't a node type?
              if (node.value && node.value.typeIndex) {
                  this.visit(node.value);
              }
              return node;
          }
          var impl = this._implementation;
          var func = this._visitInCache[nodeTypeIndex];
          var funcOut = this._visitOutCache[nodeTypeIndex];
          var visitArgs = _visitArgs;
          var fnName;
          visitArgs.visitDeeper = true;
          if (!func) {
              fnName = "visit" + node.type;
              func = impl[fnName] || _noop;
              funcOut = impl[fnName + "Out"] || _noop;
              this._visitInCache[nodeTypeIndex] = func;
              this._visitOutCache[nodeTypeIndex] = funcOut;
          }
          if (func !== _noop) {
              var newNode = func.call(impl, node, visitArgs);
              if (node && impl.isReplacing) {
                  node = newNode;
              }
          }
          if (visitArgs.visitDeeper && node) {
              if (node.length) {
                  for (var i = 0, cnt = node.length; i < cnt; i++) {
                      if (node[i].accept) {
                          node[i].accept(this);
                      }
                  }
              }
              else if (node.accept) {
                  node.accept(this);
              }
          }
          if (funcOut != _noop) {
              funcOut.call(impl, node);
          }
          return node;
      };
      Visitor.prototype.visitArray = function (nodes, nonReplacing) {
          if (!nodes) {
              return nodes;
          }
          var cnt = nodes.length;
          var i;
          // Non-replacing
          if (nonReplacing || !this._implementation.isReplacing) {
              for (i = 0; i < cnt; i++) {
                  this.visit(nodes[i]);
              }
              return nodes;
          }
          // Replacing
          var out = [];
          for (i = 0; i < cnt; i++) {
              var evald = this.visit(nodes[i]);
              if (evald === undefined) {
                  continue;
              }
              if (!evald.splice) {
                  out.push(evald);
              }
              else if (evald.length) {
                  this.flatten(evald, out);
              }
          }
          return out;
      };
      Visitor.prototype.flatten = function (arr, out) {
          if (!out) {
              out = [];
          }
          var cnt;
          var i;
          var item;
          var nestedCnt;
          var j;
          var nestedItem;
          for (i = 0, cnt = arr.length; i < cnt; i++) {
              item = arr[i];
              if (item === undefined) {
                  continue;
              }
              if (!item.splice) {
                  out.push(item);
                  continue;
              }
              for (j = 0, nestedCnt = item.length; j < nestedCnt; j++) {
                  nestedItem = item[j];
                  if (nestedItem === undefined) {
                      continue;
                  }
                  if (!nestedItem.splice) {
                      out.push(nestedItem);
                  }
                  else if (nestedItem.length) {
                      this.flatten(nestedItem, out);
                  }
              }
          }
          return out;
      };
      return Visitor;
  }());

  var ImportSequencer = /** @class */ (function () {
      function ImportSequencer(onSequencerEmpty) {
          this.imports = [];
          this.variableImports = [];
          this._onSequencerEmpty = onSequencerEmpty;
          this._currentDepth = 0;
      }
      ImportSequencer.prototype.addImport = function (callback) {
          var importSequencer = this;
          var importItem = {
              callback: callback,
              args: null,
              isReady: false
          };
          this.imports.push(importItem);
          return function () {
              var args = [];
              for (var _i = 0; _i < arguments.length; _i++) {
                  args[_i] = arguments[_i];
              }
              importItem.args = Array.prototype.slice.call(args, 0);
              importItem.isReady = true;
              importSequencer.tryRun();
          };
      };
      ImportSequencer.prototype.addVariableImport = function (callback) {
          this.variableImports.push(callback);
      };
      ImportSequencer.prototype.tryRun = function () {
          this._currentDepth++;
          try {
              while (true) {
                  while (this.imports.length > 0) {
                      var importItem = this.imports[0];
                      if (!importItem.isReady) {
                          return;
                      }
                      this.imports = this.imports.slice(1);
                      importItem.callback.apply(null, importItem.args);
                  }
                  if (this.variableImports.length === 0) {
                      break;
                  }
                  var variableImport = this.variableImports[0];
                  this.variableImports = this.variableImports.slice(1);
                  variableImport();
              }
          }
          finally {
              this._currentDepth--;
          }
          if (this._currentDepth === 0 && this._onSequencerEmpty) {
              this._onSequencerEmpty();
          }
      };
      return ImportSequencer;
  }());

  var ImportVisitor = function (importer, finish) {
      this._visitor = new Visitor(this);
      this._importer = importer;
      this._finish = finish;
      this.context = new contexts.Eval();
      this.importCount = 0;
      this.onceFileDetectionMap = {};
      this.recursionDetector = {};
      this._sequencer = new ImportSequencer(this._onSequencerEmpty.bind(this));
  };
  ImportVisitor.prototype = {
      isReplacing: false,
      run: function (root) {
          try {
              // process the contents
              this._visitor.visit(root);
          }
          catch (e) {
              this.error = e;
          }
          this.isFinished = true;
          this._sequencer.tryRun();
      },
      _onSequencerEmpty: function () {
          if (!this.isFinished) {
              return;
          }
          this._finish(this.error);
      },
      visitImport: function (importNode, visitArgs) {
          var inlineCSS = importNode.options.inline;
          if (!importNode.css || inlineCSS) {
              var context = new contexts.Eval(this.context, copyArray(this.context.frames));
              var importParent = context.frames[0];
              this.importCount++;
              if (importNode.isVariableImport()) {
                  this._sequencer.addVariableImport(this.processImportNode.bind(this, importNode, context, importParent));
              }
              else {
                  this.processImportNode(importNode, context, importParent);
              }
          }
          visitArgs.visitDeeper = false;
      },
      processImportNode: function (importNode, context, importParent) {
          var evaldImportNode;
          var inlineCSS = importNode.options.inline;
          try {
              evaldImportNode = importNode.evalForImport(context);
          }
          catch (e) {
              if (!e.filename) {
                  e.index = importNode.getIndex();
                  e.filename = importNode.fileInfo().filename;
              }
              // attempt to eval properly and treat as css
              importNode.css = true;
              // if that fails, this error will be thrown
              importNode.error = e;
          }
          if (evaldImportNode && (!evaldImportNode.css || inlineCSS)) {
              if (evaldImportNode.options.multiple) {
                  context.importMultiple = true;
              }
              // try appending if we haven't determined if it is css or not
              var tryAppendLessExtension = evaldImportNode.css === undefined;
              for (var i_1 = 0; i_1 < importParent.rules.length; i_1++) {
                  if (importParent.rules[i_1] === importNode) {
                      importParent.rules[i_1] = evaldImportNode;
                      break;
                  }
              }
              var onImported = this.onImported.bind(this, evaldImportNode, context);
              var sequencedOnImported = this._sequencer.addImport(onImported);
              this._importer.push(evaldImportNode.getPath(), tryAppendLessExtension, evaldImportNode.fileInfo(), evaldImportNode.options, sequencedOnImported);
          }
          else {
              this.importCount--;
              if (this.isFinished) {
                  this._sequencer.tryRun();
              }
          }
      },
      onImported: function (importNode, context, e, root, importedAtRoot, fullPath) {
          if (e) {
              if (!e.filename) {
                  e.index = importNode.getIndex();
                  e.filename = importNode.fileInfo().filename;
              }
              this.error = e;
          }
          var importVisitor = this;
          var inlineCSS = importNode.options.inline;
          var isPlugin = importNode.options.isPlugin;
          var isOptional = importNode.options.optional;
          var duplicateImport = importedAtRoot || fullPath in importVisitor.recursionDetector;
          if (!context.importMultiple) {
              if (duplicateImport) {
                  importNode.skip = true;
              }
              else {
                  importNode.skip = function () {
                      if (fullPath in importVisitor.onceFileDetectionMap) {
                          return true;
                      }
                      importVisitor.onceFileDetectionMap[fullPath] = true;
                      return false;
                  };
              }
          }
          if (!fullPath && isOptional) {
              importNode.skip = true;
          }
          if (root) {
              importNode.root = root;
              importNode.importedFilename = fullPath;
              if (!inlineCSS && !isPlugin && (context.importMultiple || !duplicateImport)) {
                  importVisitor.recursionDetector[fullPath] = true;
                  var oldContext = this.context;
                  this.context = context;
                  try {
                      this._visitor.visit(root);
                  }
                  catch (e) {
                      this.error = e;
                  }
                  this.context = oldContext;
              }
          }
          importVisitor.importCount--;
          if (importVisitor.isFinished) {
              importVisitor._sequencer.tryRun();
          }
      },
      visitDeclaration: function (declNode, visitArgs) {
          if (declNode.value.type === 'DetachedRuleset') {
              this.context.frames.unshift(declNode);
          }
          else {
              visitArgs.visitDeeper = false;
          }
      },
      visitDeclarationOut: function (declNode) {
          if (declNode.value.type === 'DetachedRuleset') {
              this.context.frames.shift();
          }
      },
      visitAtRule: function (atRuleNode, visitArgs) {
          this.context.frames.unshift(atRuleNode);
      },
      visitAtRuleOut: function (atRuleNode) {
          this.context.frames.shift();
      },
      visitMixinDefinition: function (mixinDefinitionNode, visitArgs) {
          this.context.frames.unshift(mixinDefinitionNode);
      },
      visitMixinDefinitionOut: function (mixinDefinitionNode) {
          this.context.frames.shift();
      },
      visitRuleset: function (rulesetNode, visitArgs) {
          this.context.frames.unshift(rulesetNode);
      },
      visitRulesetOut: function (rulesetNode) {
          this.context.frames.shift();
      },
      visitMedia: function (mediaNode, visitArgs) {
          this.context.frames.unshift(mediaNode.rules[0]);
      },
      visitMediaOut: function (mediaNode) {
          this.context.frames.shift();
      }
  };

  var SetTreeVisibilityVisitor = /** @class */ (function () {
      function SetTreeVisibilityVisitor(visible) {
          this.visible = visible;
      }
      SetTreeVisibilityVisitor.prototype.run = function (root) {
          this.visit(root);
      };
      SetTreeVisibilityVisitor.prototype.visitArray = function (nodes) {
          if (!nodes) {
              return nodes;
          }
          var cnt = nodes.length;
          var i;
          for (i = 0; i < cnt; i++) {
              this.visit(nodes[i]);
          }
          return nodes;
      };
      SetTreeVisibilityVisitor.prototype.visit = function (node) {
          if (!node) {
              return node;
          }
          if (node.constructor === Array) {
              return this.visitArray(node);
          }
          if (!node.blocksVisibility || node.blocksVisibility()) {
              return node;
          }
          if (this.visible) {
              node.ensureVisibility();
          }
          else {
              node.ensureInvisibility();
          }
          node.accept(this);
          return node;
      };
      return SetTreeVisibilityVisitor;
  }());

  /* jshint loopfunc:true */
  var ExtendFinderVisitor = /** @class */ (function () {
      function ExtendFinderVisitor() {
          this._visitor = new Visitor(this);
          this.contexts = [];
          this.allExtendsStack = [[]];
      }
      ExtendFinderVisitor.prototype.run = function (root) {
          root = this._visitor.visit(root);
          root.allExtends = this.allExtendsStack[0];
          return root;
      };
      ExtendFinderVisitor.prototype.visitDeclaration = function (declNode, visitArgs) {
          visitArgs.visitDeeper = false;
      };
      ExtendFinderVisitor.prototype.visitMixinDefinition = function (mixinDefinitionNode, visitArgs) {
          visitArgs.visitDeeper = false;
      };
      ExtendFinderVisitor.prototype.visitRuleset = function (rulesetNode, visitArgs) {
          if (rulesetNode.root) {
              return;
          }
          var i;
          var j;
          var extend;
          var allSelectorsExtendList = [];
          var extendList;
          // get &:extend(.a); rules which apply to all selectors in this ruleset
          var rules = rulesetNode.rules;
          var ruleCnt = rules ? rules.length : 0;
          for (i = 0; i < ruleCnt; i++) {
              if (rulesetNode.rules[i] instanceof tree.Extend) {
                  allSelectorsExtendList.push(rules[i]);
                  rulesetNode.extendOnEveryPath = true;
              }
          }
          // now find every selector and apply the extends that apply to all extends
          // and the ones which apply to an individual extend
          var paths = rulesetNode.paths;
          for (i = 0; i < paths.length; i++) {
              var selectorPath = paths[i];
              var selector = selectorPath[selectorPath.length - 1];
              var selExtendList = selector.extendList;
              extendList = selExtendList ? copyArray(selExtendList).concat(allSelectorsExtendList)
                  : allSelectorsExtendList;
              if (extendList) {
                  extendList = extendList.map(function (allSelectorsExtend) { return allSelectorsExtend.clone(); });
              }
              for (j = 0; j < extendList.length; j++) {
                  this.foundExtends = true;
                  extend = extendList[j];
                  extend.findSelfSelectors(selectorPath);
                  extend.ruleset = rulesetNode;
                  if (j === 0) {
                      extend.firstExtendOnThisSelectorPath = true;
                  }
                  this.allExtendsStack[this.allExtendsStack.length - 1].push(extend);
              }
          }
          this.contexts.push(rulesetNode.selectors);
      };
      ExtendFinderVisitor.prototype.visitRulesetOut = function (rulesetNode) {
          if (!rulesetNode.root) {
              this.contexts.length = this.contexts.length - 1;
          }
      };
      ExtendFinderVisitor.prototype.visitMedia = function (mediaNode, visitArgs) {
          mediaNode.allExtends = [];
          this.allExtendsStack.push(mediaNode.allExtends);
      };
      ExtendFinderVisitor.prototype.visitMediaOut = function (mediaNode) {
          this.allExtendsStack.length = this.allExtendsStack.length - 1;
      };
      ExtendFinderVisitor.prototype.visitAtRule = function (atRuleNode, visitArgs) {
          atRuleNode.allExtends = [];
          this.allExtendsStack.push(atRuleNode.allExtends);
      };
      ExtendFinderVisitor.prototype.visitAtRuleOut = function (atRuleNode) {
          this.allExtendsStack.length = this.allExtendsStack.length - 1;
      };
      return ExtendFinderVisitor;
  }());
  var ProcessExtendsVisitor = /** @class */ (function () {
      function ProcessExtendsVisitor() {
          this._visitor = new Visitor(this);
      }
      ProcessExtendsVisitor.prototype.run = function (root) {
          var extendFinder = new ExtendFinderVisitor();
          this.extendIndices = {};
          extendFinder.run(root);
          if (!extendFinder.foundExtends) {
              return root;
          }
          root.allExtends = root.allExtends.concat(this.doExtendChaining(root.allExtends, root.allExtends));
          this.allExtendsStack = [root.allExtends];
          var newRoot = this._visitor.visit(root);
          this.checkExtendsForNonMatched(root.allExtends);
          return newRoot;
      };
      ProcessExtendsVisitor.prototype.checkExtendsForNonMatched = function (extendList) {
          var indices = this.extendIndices;
          extendList.filter(function (extend) { return !extend.hasFoundMatches && extend.parent_ids.length == 1; }).forEach(function (extend) {
              var selector = '_unknown_';
              try {
                  selector = extend.selector.toCSS({});
              }
              catch (_) { }
              if (!indices[extend.index + " " + selector]) {
                  indices[extend.index + " " + selector] = true;
                  logger.warn("extend '" + selector + "' has no matches");
              }
          });
      };
      ProcessExtendsVisitor.prototype.doExtendChaining = function (extendsList, extendsListTarget, iterationCount) {
          //
          // chaining is different from normal extension.. if we extend an extend then we are not just copying, altering
          // and pasting the selector we would do normally, but we are also adding an extend with the same target selector
          // this means this new extend can then go and alter other extends
          //
          // this method deals with all the chaining work - without it, extend is flat and doesn't work on other extend selectors
          // this is also the most expensive.. and a match on one selector can cause an extension of a selector we had already
          // processed if we look at each selector at a time, as is done in visitRuleset
          var extendIndex;
          var targetExtendIndex;
          var matches;
          var extendsToAdd = [];
          var newSelector;
          var extendVisitor = this;
          var selectorPath;
          var extend;
          var targetExtend;
          var newExtend;
          iterationCount = iterationCount || 0;
          // loop through comparing every extend with every target extend.
          // a target extend is the one on the ruleset we are looking at copy/edit/pasting in place
          // e.g.  .a:extend(.b) {}  and .b:extend(.c) {} then the first extend extends the second one
          // and the second is the target.
          // the separation into two lists allows us to process a subset of chains with a bigger set, as is the
          // case when processing media queries
          for (extendIndex = 0; extendIndex < extendsList.length; extendIndex++) {
              for (targetExtendIndex = 0; targetExtendIndex < extendsListTarget.length; targetExtendIndex++) {
                  extend = extendsList[extendIndex];
                  targetExtend = extendsListTarget[targetExtendIndex];
                  // look for circular references
                  if (extend.parent_ids.indexOf(targetExtend.object_id) >= 0) {
                      continue;
                  }
                  // find a match in the target extends self selector (the bit before :extend)
                  selectorPath = [targetExtend.selfSelectors[0]];
                  matches = extendVisitor.findMatch(extend, selectorPath);
                  if (matches.length) {
                      extend.hasFoundMatches = true;
                      // we found a match, so for each self selector..
                      extend.selfSelectors.forEach(function (selfSelector) {
                          var info = targetExtend.visibilityInfo();
                          // process the extend as usual
                          newSelector = extendVisitor.extendSelector(matches, selectorPath, selfSelector, extend.isVisible());
                          // but now we create a new extend from it
                          newExtend = new (tree.Extend)(targetExtend.selector, targetExtend.option, 0, targetExtend.fileInfo(), info);
                          newExtend.selfSelectors = newSelector;
                          // add the extend onto the list of extends for that selector
                          newSelector[newSelector.length - 1].extendList = [newExtend];
                          // record that we need to add it.
                          extendsToAdd.push(newExtend);
                          newExtend.ruleset = targetExtend.ruleset;
                          // remember its parents for circular references
                          newExtend.parent_ids = newExtend.parent_ids.concat(targetExtend.parent_ids, extend.parent_ids);
                          // only process the selector once.. if we have :extend(.a,.b) then multiple
                          // extends will look at the same selector path, so when extending
                          // we know that any others will be duplicates in terms of what is added to the css
                          if (targetExtend.firstExtendOnThisSelectorPath) {
                              newExtend.firstExtendOnThisSelectorPath = true;
                              targetExtend.ruleset.paths.push(newSelector);
                          }
                      });
                  }
              }
          }
          if (extendsToAdd.length) {
              // try to detect circular references to stop a stack overflow.
              // may no longer be needed.
              this.extendChainCount++;
              if (iterationCount > 100) {
                  var selectorOne = '{unable to calculate}';
                  var selectorTwo = '{unable to calculate}';
                  try {
                      selectorOne = extendsToAdd[0].selfSelectors[0].toCSS();
                      selectorTwo = extendsToAdd[0].selector.toCSS();
                  }
                  catch (e) { }
                  throw { message: "extend circular reference detected. One of the circular extends is currently:" + selectorOne + ":extend(" + selectorTwo + ")" };
              }
              // now process the new extends on the existing rules so that we can handle a extending b extending c extending
              // d extending e...
              return extendsToAdd.concat(extendVisitor.doExtendChaining(extendsToAdd, extendsListTarget, iterationCount + 1));
          }
          else {
              return extendsToAdd;
          }
      };
      ProcessExtendsVisitor.prototype.visitDeclaration = function (ruleNode, visitArgs) {
          visitArgs.visitDeeper = false;
      };
      ProcessExtendsVisitor.prototype.visitMixinDefinition = function (mixinDefinitionNode, visitArgs) {
          visitArgs.visitDeeper = false;
      };
      ProcessExtendsVisitor.prototype.visitSelector = function (selectorNode, visitArgs) {
          visitArgs.visitDeeper = false;
      };
      ProcessExtendsVisitor.prototype.visitRuleset = function (rulesetNode, visitArgs) {
          if (rulesetNode.root) {
              return;
          }
          var matches;
          var pathIndex;
          var extendIndex;
          var allExtends = this.allExtendsStack[this.allExtendsStack.length - 1];
          var selectorsToAdd = [];
          var extendVisitor = this;
          var selectorPath;
          // look at each selector path in the ruleset, find any extend matches and then copy, find and replace
          for (extendIndex = 0; extendIndex < allExtends.length; extendIndex++) {
              for (pathIndex = 0; pathIndex < rulesetNode.paths.length; pathIndex++) {
                  selectorPath = rulesetNode.paths[pathIndex];
                  // extending extends happens initially, before the main pass
                  if (rulesetNode.extendOnEveryPath) {
                      continue;
                  }
                  var extendList = selectorPath[selectorPath.length - 1].extendList;
                  if (extendList && extendList.length) {
                      continue;
                  }
                  matches = this.findMatch(allExtends[extendIndex], selectorPath);
                  if (matches.length) {
                      allExtends[extendIndex].hasFoundMatches = true;
                      allExtends[extendIndex].selfSelectors.forEach(function (selfSelector) {
                          var extendedSelectors;
                          extendedSelectors = extendVisitor.extendSelector(matches, selectorPath, selfSelector, allExtends[extendIndex].isVisible());
                          selectorsToAdd.push(extendedSelectors);
                      });
                  }
              }
          }
          rulesetNode.paths = rulesetNode.paths.concat(selectorsToAdd);
      };
      ProcessExtendsVisitor.prototype.findMatch = function (extend, haystackSelectorPath) {
          //
          // look through the haystack selector path to try and find the needle - extend.selector
          // returns an array of selector matches that can then be replaced
          //
          var haystackSelectorIndex;
          var hackstackSelector;
          var hackstackElementIndex;
          var haystackElement;
          var targetCombinator;
          var i;
          var extendVisitor = this;
          var needleElements = extend.selector.elements;
          var potentialMatches = [];
          var potentialMatch;
          var matches = [];
          // loop through the haystack elements
          for (haystackSelectorIndex = 0; haystackSelectorIndex < haystackSelectorPath.length; haystackSelectorIndex++) {
              hackstackSelector = haystackSelectorPath[haystackSelectorIndex];
              for (hackstackElementIndex = 0; hackstackElementIndex < hackstackSelector.elements.length; hackstackElementIndex++) {
                  haystackElement = hackstackSelector.elements[hackstackElementIndex];
                  // if we allow elements before our match we can add a potential match every time. otherwise only at the first element.
                  if (extend.allowBefore || (haystackSelectorIndex === 0 && hackstackElementIndex === 0)) {
                      potentialMatches.push({ pathIndex: haystackSelectorIndex, index: hackstackElementIndex, matched: 0,
                          initialCombinator: haystackElement.combinator });
                  }
                  for (i = 0; i < potentialMatches.length; i++) {
                      potentialMatch = potentialMatches[i];
                      // selectors add " " onto the first element. When we use & it joins the selectors together, but if we don't
                      // then each selector in haystackSelectorPath has a space before it added in the toCSS phase. so we need to
                      // work out what the resulting combinator will be
                      targetCombinator = haystackElement.combinator.value;
                      if (targetCombinator === '' && hackstackElementIndex === 0) {
                          targetCombinator = ' ';
                      }
                      // if we don't match, null our match to indicate failure
                      if (!extendVisitor.isElementValuesEqual(needleElements[potentialMatch.matched].value, haystackElement.value) ||
                          (potentialMatch.matched > 0 && needleElements[potentialMatch.matched].combinator.value !== targetCombinator)) {
                          potentialMatch = null;
                      }
                      else {
                          potentialMatch.matched++;
                      }
                      // if we are still valid and have finished, test whether we have elements after and whether these are allowed
                      if (potentialMatch) {
                          potentialMatch.finished = potentialMatch.matched === needleElements.length;
                          if (potentialMatch.finished &&
                              (!extend.allowAfter &&
                                  (hackstackElementIndex + 1 < hackstackSelector.elements.length || haystackSelectorIndex + 1 < haystackSelectorPath.length))) {
                              potentialMatch = null;
                          }
                      }
                      // if null we remove, if not, we are still valid, so either push as a valid match or continue
                      if (potentialMatch) {
                          if (potentialMatch.finished) {
                              potentialMatch.length = needleElements.length;
                              potentialMatch.endPathIndex = haystackSelectorIndex;
                              potentialMatch.endPathElementIndex = hackstackElementIndex + 1; // index after end of match
                              potentialMatches.length = 0; // we don't allow matches to overlap, so start matching again
                              matches.push(potentialMatch);
                          }
                      }
                      else {
                          potentialMatches.splice(i, 1);
                          i--;
                      }
                  }
              }
          }
          return matches;
      };
      ProcessExtendsVisitor.prototype.isElementValuesEqual = function (elementValue1, elementValue2) {
          if (typeof elementValue1 === 'string' || typeof elementValue2 === 'string') {
              return elementValue1 === elementValue2;
          }
          if (elementValue1 instanceof tree.Attribute) {
              if (elementValue1.op !== elementValue2.op || elementValue1.key !== elementValue2.key) {
                  return false;
              }
              if (!elementValue1.value || !elementValue2.value) {
                  if (elementValue1.value || elementValue2.value) {
                      return false;
                  }
                  return true;
              }
              elementValue1 = elementValue1.value.value || elementValue1.value;
              elementValue2 = elementValue2.value.value || elementValue2.value;
              return elementValue1 === elementValue2;
          }
          elementValue1 = elementValue1.value;
          elementValue2 = elementValue2.value;
          if (elementValue1 instanceof tree.Selector) {
              if (!(elementValue2 instanceof tree.Selector) || elementValue1.elements.length !== elementValue2.elements.length) {
                  return false;
              }
              for (var i_1 = 0; i_1 < elementValue1.elements.length; i_1++) {
                  if (elementValue1.elements[i_1].combinator.value !== elementValue2.elements[i_1].combinator.value) {
                      if (i_1 !== 0 || (elementValue1.elements[i_1].combinator.value || ' ') !== (elementValue2.elements[i_1].combinator.value || ' ')) {
                          return false;
                      }
                  }
                  if (!this.isElementValuesEqual(elementValue1.elements[i_1].value, elementValue2.elements[i_1].value)) {
                      return false;
                  }
              }
              return true;
          }
          return false;
      };
      ProcessExtendsVisitor.prototype.extendSelector = function (matches, selectorPath, replacementSelector, isVisible) {
          // for a set of matches, replace each match with the replacement selector
          var currentSelectorPathIndex = 0;
          var currentSelectorPathElementIndex = 0;
          var path = [];
          var matchIndex;
          var selector;
          var firstElement;
          var match;
          var newElements;
          for (matchIndex = 0; matchIndex < matches.length; matchIndex++) {
              match = matches[matchIndex];
              selector = selectorPath[match.pathIndex];
              firstElement = new tree.Element(match.initialCombinator, replacementSelector.elements[0].value, replacementSelector.elements[0].isVariable, replacementSelector.elements[0].getIndex(), replacementSelector.elements[0].fileInfo());
              if (match.pathIndex > currentSelectorPathIndex && currentSelectorPathElementIndex > 0) {
                  path[path.length - 1].elements = path[path.length - 1]
                      .elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
                  currentSelectorPathElementIndex = 0;
                  currentSelectorPathIndex++;
              }
              newElements = selector.elements
                  .slice(currentSelectorPathElementIndex, match.index)
                  .concat([firstElement])
                  .concat(replacementSelector.elements.slice(1));
              if (currentSelectorPathIndex === match.pathIndex && matchIndex > 0) {
                  path[path.length - 1].elements =
                      path[path.length - 1].elements.concat(newElements);
              }
              else {
                  path = path.concat(selectorPath.slice(currentSelectorPathIndex, match.pathIndex));
                  path.push(new tree.Selector(newElements));
              }
              currentSelectorPathIndex = match.endPathIndex;
              currentSelectorPathElementIndex = match.endPathElementIndex;
              if (currentSelectorPathElementIndex >= selectorPath[currentSelectorPathIndex].elements.length) {
                  currentSelectorPathElementIndex = 0;
                  currentSelectorPathIndex++;
              }
          }
          if (currentSelectorPathIndex < selectorPath.length && currentSelectorPathElementIndex > 0) {
              path[path.length - 1].elements = path[path.length - 1]
                  .elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
              currentSelectorPathIndex++;
          }
          path = path.concat(selectorPath.slice(currentSelectorPathIndex, selectorPath.length));
          path = path.map(function (currentValue) {
              // we can re-use elements here, because the visibility property matters only for selectors
              var derived = currentValue.createDerived(currentValue.elements);
              if (isVisible) {
                  derived.ensureVisibility();
              }
              else {
                  derived.ensureInvisibility();
              }
              return derived;
          });
          return path;
      };
      ProcessExtendsVisitor.prototype.visitMedia = function (mediaNode, visitArgs) {
          var newAllExtends = mediaNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length - 1]);
          newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, mediaNode.allExtends));
          this.allExtendsStack.push(newAllExtends);
      };
      ProcessExtendsVisitor.prototype.visitMediaOut = function (mediaNode) {
          var lastIndex = this.allExtendsStack.length - 1;
          this.allExtendsStack.length = lastIndex;
      };
      ProcessExtendsVisitor.prototype.visitAtRule = function (atRuleNode, visitArgs) {
          var newAllExtends = atRuleNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length - 1]);
          newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, atRuleNode.allExtends));
          this.allExtendsStack.push(newAllExtends);
      };
      ProcessExtendsVisitor.prototype.visitAtRuleOut = function (atRuleNode) {
          var lastIndex = this.allExtendsStack.length - 1;
          this.allExtendsStack.length = lastIndex;
      };
      return ProcessExtendsVisitor;
  }());

  var JoinSelectorVisitor = /** @class */ (function () {
      function JoinSelectorVisitor() {
          this.contexts = [[]];
          this._visitor = new Visitor(this);
      }
      JoinSelectorVisitor.prototype.run = function (root) {
          return this._visitor.visit(root);
      };
      JoinSelectorVisitor.prototype.visitDeclaration = function (declNode, visitArgs) {
          visitArgs.visitDeeper = false;
      };
      JoinSelectorVisitor.prototype.visitMixinDefinition = function (mixinDefinitionNode, visitArgs) {
          visitArgs.visitDeeper = false;
      };
      JoinSelectorVisitor.prototype.visitRuleset = function (rulesetNode, visitArgs) {
          var context = this.contexts[this.contexts.length - 1];
          var paths = [];
          var selectors;
          this.contexts.push(paths);
          if (!rulesetNode.root) {
              selectors = rulesetNode.selectors;
              if (selectors) {
                  selectors = selectors.filter(function (selector) { return selector.getIsOutput(); });
                  rulesetNode.selectors = selectors.length ? selectors : (selectors = null);
                  if (selectors) {
                      rulesetNode.joinSelectors(paths, context, selectors);
                  }
              }
              if (!selectors) {
                  rulesetNode.rules = null;
              }
              rulesetNode.paths = paths;
          }
      };
      JoinSelectorVisitor.prototype.visitRulesetOut = function (rulesetNode) {
          this.contexts.length = this.contexts.length - 1;
      };
      JoinSelectorVisitor.prototype.visitMedia = function (mediaNode, visitArgs) {
          var context = this.contexts[this.contexts.length - 1];
          mediaNode.rules[0].root = (context.length === 0 || context[0].multiMedia);
      };
      JoinSelectorVisitor.prototype.visitAtRule = function (atRuleNode, visitArgs) {
          var context = this.contexts[this.contexts.length - 1];
          if (atRuleNode.rules && atRuleNode.rules.length) {
              atRuleNode.rules[0].root = (atRuleNode.isRooted || context.length === 0 || null);
          }
      };
      return JoinSelectorVisitor;
  }());

  var CSSVisitorUtils = /** @class */ (function () {
      function CSSVisitorUtils(context) {
          this._visitor = new Visitor(this);
          this._context = context;
      }
      CSSVisitorUtils.prototype.containsSilentNonBlockedChild = function (bodyRules) {
          var rule;
          if (!bodyRules) {
              return false;
          }
          for (var r = 0; r < bodyRules.length; r++) {
              rule = bodyRules[r];
              if (rule.isSilent && rule.isSilent(this._context) && !rule.blocksVisibility()) {
                  // the atrule contains something that was referenced (likely by extend)
                  // therefore it needs to be shown in output too
                  return true;
              }
          }
          return false;
      };
      CSSVisitorUtils.prototype.keepOnlyVisibleChilds = function (owner) {
          if (owner && owner.rules) {
              owner.rules = owner.rules.filter(function (thing) { return thing.isVisible(); });
          }
      };
      CSSVisitorUtils.prototype.isEmpty = function (owner) {
          return (owner && owner.rules)
              ? (owner.rules.length === 0) : true;
      };
      CSSVisitorUtils.prototype.hasVisibleSelector = function (rulesetNode) {
          return (rulesetNode && rulesetNode.paths)
              ? (rulesetNode.paths.length > 0) : false;
      };
      CSSVisitorUtils.prototype.resolveVisibility = function (node, originalRules) {
          if (!node.blocksVisibility()) {
              if (this.isEmpty(node) && !this.containsSilentNonBlockedChild(originalRules)) {
                  return;
              }
              return node;
          }
          var compiledRulesBody = node.rules[0];
          this.keepOnlyVisibleChilds(compiledRulesBody);
          if (this.isEmpty(compiledRulesBody)) {
              return;
          }
          node.ensureVisibility();
          node.removeVisibilityBlock();
          return node;
      };
      CSSVisitorUtils.prototype.isVisibleRuleset = function (rulesetNode) {
          if (rulesetNode.firstRoot) {
              return true;
          }
          if (this.isEmpty(rulesetNode)) {
              return false;
          }
          if (!rulesetNode.root && !this.hasVisibleSelector(rulesetNode)) {
              return false;
          }
          return true;
      };
      return CSSVisitorUtils;
  }());
  var ToCSSVisitor = function (context) {
      this._visitor = new Visitor(this);
      this._context = context;
      this.utils = new CSSVisitorUtils(context);
  };
  ToCSSVisitor.prototype = {
      isReplacing: true,
      run: function (root) {
          return this._visitor.visit(root);
      },
      visitDeclaration: function (declNode, visitArgs) {
          if (declNode.blocksVisibility() || declNode.variable) {
              return;
          }
          return declNode;
      },
      visitMixinDefinition: function (mixinNode, visitArgs) {
          // mixin definitions do not get eval'd - this means they keep state
          // so we have to clear that state here so it isn't used if toCSS is called twice
          mixinNode.frames = [];
      },
      visitExtend: function (extendNode, visitArgs) {
      },
      visitComment: function (commentNode, visitArgs) {
          if (commentNode.blocksVisibility() || commentNode.isSilent(this._context)) {
              return;
          }
          return commentNode;
      },
      visitMedia: function (mediaNode, visitArgs) {
          var originalRules = mediaNode.rules[0].rules;
          mediaNode.accept(this._visitor);
          visitArgs.visitDeeper = false;
          return this.utils.resolveVisibility(mediaNode, originalRules);
      },
      visitImport: function (importNode, visitArgs) {
          if (importNode.blocksVisibility()) {
              return;
          }
          return importNode;
      },
      visitAtRule: function (atRuleNode, visitArgs) {
          if (atRuleNode.rules && atRuleNode.rules.length) {
              return this.visitAtRuleWithBody(atRuleNode, visitArgs);
          }
          else {
              return this.visitAtRuleWithoutBody(atRuleNode, visitArgs);
          }
      },
      visitAnonymous: function (anonymousNode, visitArgs) {
          if (!anonymousNode.blocksVisibility()) {
              anonymousNode.accept(this._visitor);
              return anonymousNode;
          }
      },
      visitAtRuleWithBody: function (atRuleNode, visitArgs) {
          // if there is only one nested ruleset and that one has no path, then it is
          // just fake ruleset
          function hasFakeRuleset(atRuleNode) {
              var bodyRules = atRuleNode.rules;
              return bodyRules.length === 1 && (!bodyRules[0].paths || bodyRules[0].paths.length === 0);
          }
          function getBodyRules(atRuleNode) {
              var nodeRules = atRuleNode.rules;
              if (hasFakeRuleset(atRuleNode)) {
                  return nodeRules[0].rules;
              }
              return nodeRules;
          }
          // it is still true that it is only one ruleset in array
          // this is last such moment
          // process childs
          var originalRules = getBodyRules(atRuleNode);
          atRuleNode.accept(this._visitor);
          visitArgs.visitDeeper = false;
          if (!this.utils.isEmpty(atRuleNode)) {
              this._mergeRules(atRuleNode.rules[0].rules);
          }
          return this.utils.resolveVisibility(atRuleNode, originalRules);
      },
      visitAtRuleWithoutBody: function (atRuleNode, visitArgs) {
          if (atRuleNode.blocksVisibility()) {
              return;
          }
          if (atRuleNode.name === '@charset') {
              // Only output the debug info together with subsequent @charset definitions
              // a comment (or @media statement) before the actual @charset atrule would
              // be considered illegal css as it has to be on the first line
              if (this.charset) {
                  if (atRuleNode.debugInfo) {
                      var comment = new tree.Comment("/* " + atRuleNode.toCSS(this._context).replace(/\n/g, '') + " */\n");
                      comment.debugInfo = atRuleNode.debugInfo;
                      return this._visitor.visit(comment);
                  }
                  return;
              }
              this.charset = true;
          }
          return atRuleNode;
      },
      checkValidNodes: function (rules, isRoot) {
          if (!rules) {
              return;
          }
          for (var i_1 = 0; i_1 < rules.length; i_1++) {
              var ruleNode = rules[i_1];
              if (isRoot && ruleNode instanceof tree.Declaration && !ruleNode.variable) {
                  throw { message: 'Properties must be inside selector blocks. They cannot be in the root',
                      index: ruleNode.getIndex(), filename: ruleNode.fileInfo() && ruleNode.fileInfo().filename };
              }
              if (ruleNode instanceof tree.Call) {
                  throw { message: "Function '" + ruleNode.name + "' is undefined",
                      index: ruleNode.getIndex(), filename: ruleNode.fileInfo() && ruleNode.fileInfo().filename };
              }
              if (ruleNode.type && !ruleNode.allowRoot) {
                  throw { message: ruleNode.type + " node returned by a function is not valid here",
                      index: ruleNode.getIndex(), filename: ruleNode.fileInfo() && ruleNode.fileInfo().filename };
              }
          }
      },
      visitRuleset: function (rulesetNode, visitArgs) {
          // at this point rulesets are nested into each other
          var rule;
          var rulesets = [];
          this.checkValidNodes(rulesetNode.rules, rulesetNode.firstRoot);
          if (!rulesetNode.root) {
              // remove invisible paths
              this._compileRulesetPaths(rulesetNode);
              // remove rulesets from this ruleset body and compile them separately
              var nodeRules = rulesetNode.rules;
              var nodeRuleCnt = nodeRules ? nodeRules.length : 0;
              for (var i_2 = 0; i_2 < nodeRuleCnt;) {
                  rule = nodeRules[i_2];
                  if (rule && rule.rules) {
                      // visit because we are moving them out from being a child
                      rulesets.push(this._visitor.visit(rule));
                      nodeRules.splice(i_2, 1);
                      nodeRuleCnt--;
                      continue;
                  }
                  i_2++;
              }
              // accept the visitor to remove rules and refactor itself
              // then we can decide nogw whether we want it or not
              // compile body
              if (nodeRuleCnt > 0) {
                  rulesetNode.accept(this._visitor);
              }
              else {
                  rulesetNode.rules = null;
              }
              visitArgs.visitDeeper = false;
          }
          else { // if (! rulesetNode.root) {
              rulesetNode.accept(this._visitor);
              visitArgs.visitDeeper = false;
          }
          if (rulesetNode.rules) {
              this._mergeRules(rulesetNode.rules);
              this._removeDuplicateRules(rulesetNode.rules);
          }
          // now decide whether we keep the ruleset
          if (this.utils.isVisibleRuleset(rulesetNode)) {
              rulesetNode.ensureVisibility();
              rulesets.splice(0, 0, rulesetNode);
          }
          if (rulesets.length === 1) {
              return rulesets[0];
          }
          return rulesets;
      },
      _compileRulesetPaths: function (rulesetNode) {
          if (rulesetNode.paths) {
              rulesetNode.paths = rulesetNode.paths
                  .filter(function (p) {
                  var i;
                  if (p[0].elements[0].combinator.value === ' ') {
                      p[0].elements[0].combinator = new (tree.Combinator)('');
                  }
                  for (i = 0; i < p.length; i++) {
                      if (p[i].isVisible() && p[i].getIsOutput()) {
                          return true;
                      }
                  }
                  return false;
              });
          }
      },
      _removeDuplicateRules: function (rules) {
          if (!rules) {
              return;
          }
          // remove duplicates
          var ruleCache = {};
          var ruleList;
          var rule;
          var i;
          for (i = rules.length - 1; i >= 0; i--) {
              rule = rules[i];
              if (rule instanceof tree.Declaration) {
                  if (!ruleCache[rule.name]) {
                      ruleCache[rule.name] = rule;
                  }
                  else {
                      ruleList = ruleCache[rule.name];
                      if (ruleList instanceof tree.Declaration) {
                          ruleList = ruleCache[rule.name] = [ruleCache[rule.name].toCSS(this._context)];
                      }
                      var ruleCSS = rule.toCSS(this._context);
                      if (ruleList.indexOf(ruleCSS) !== -1) {
                          rules.splice(i, 1);
                      }
                      else {
                          ruleList.push(ruleCSS);
                      }
                  }
              }
          }
      },
      _mergeRules: function (rules) {
          if (!rules) {
              return;
          }
          var groups = {};
          var groupsArr = [];
          for (var i_3 = 0; i_3 < rules.length; i_3++) {
              var rule = rules[i_3];
              if (rule.merge) {
                  var key = rule.name;
                  groups[key] ? rules.splice(i_3--, 1) :
                      groupsArr.push(groups[key] = []);
                  groups[key].push(rule);
              }
          }
          groupsArr.forEach(function (group) {
              if (group.length > 0) {
                  var result_1 = group[0];
                  var space_1 = [];
                  var comma_1 = [new tree.Expression(space_1)];
                  group.forEach(function (rule) {
                      if ((rule.merge === '+') && (space_1.length > 0)) {
                          comma_1.push(new tree.Expression(space_1 = []));
                      }
                      space_1.push(rule.value);
                      result_1.important = result_1.important || rule.important;
                  });
                  result_1.value = new tree.Value(comma_1);
              }
          });
      }
  };

  var visitors = {
      Visitor: Visitor,
      ImportVisitor: ImportVisitor,
      MarkVisibleSelectorsVisitor: SetTreeVisibilityVisitor,
      ExtendVisitor: ProcessExtendsVisitor,
      JoinSelectorVisitor: JoinSelectorVisitor,
      ToCSSVisitor: ToCSSVisitor
  };

  // Split the input into chunks.
  var chunker = (function (input, fail) {
      var len = input.length;
      var level = 0;
      var parenLevel = 0;
      var lastOpening;
      var lastOpeningParen;
      var lastMultiComment;
      var lastMultiCommentEndBrace;
      var chunks = [];
      var emitFrom = 0;
      var chunkerCurrentIndex;
      var currentChunkStartIndex;
      var cc;
      var cc2;
      var matched;
      function emitChunk(force) {
          var len = chunkerCurrentIndex - emitFrom;
          if (((len < 512) && !force) || !len) {
              return;
          }
          chunks.push(input.slice(emitFrom, chunkerCurrentIndex + 1));
          emitFrom = chunkerCurrentIndex + 1;
      }
      for (chunkerCurrentIndex = 0; chunkerCurrentIndex < len; chunkerCurrentIndex++) {
          cc = input.charCodeAt(chunkerCurrentIndex);
          if (((cc >= 97) && (cc <= 122)) || (cc < 34)) {
              // a-z or whitespace
              continue;
          }
          switch (cc) {
              case 40: // (
                  parenLevel++;
                  lastOpeningParen = chunkerCurrentIndex;
                  continue;
              case 41: // )
                  if (--parenLevel < 0) {
                      return fail('missing opening `(`', chunkerCurrentIndex);
                  }
                  continue;
              case 59: // ;
                  if (!parenLevel) {
                      emitChunk();
                  }
                  continue;
              case 123: // {
                  level++;
                  lastOpening = chunkerCurrentIndex;
                  continue;
              case 125: // }
                  if (--level < 0) {
                      return fail('missing opening `{`', chunkerCurrentIndex);
                  }
                  if (!level && !parenLevel) {
                      emitChunk();
                  }
                  continue;
              case 92: // \
                  if (chunkerCurrentIndex < len - 1) {
                      chunkerCurrentIndex++;
                      continue;
                  }
                  return fail('unescaped `\\`', chunkerCurrentIndex);
              case 34:
              case 39:
              case 96: // ", ' and `
                  matched = 0;
                  currentChunkStartIndex = chunkerCurrentIndex;
                  for (chunkerCurrentIndex = chunkerCurrentIndex + 1; chunkerCurrentIndex < len; chunkerCurrentIndex++) {
                      cc2 = input.charCodeAt(chunkerCurrentIndex);
                      if (cc2 > 96) {
                          continue;
                      }
                      if (cc2 == cc) {
                          matched = 1;
                          break;
                      }
                      if (cc2 == 92) { // \
                          if (chunkerCurrentIndex == len - 1) {
                              return fail('unescaped `\\`', chunkerCurrentIndex);
                          }
                          chunkerCurrentIndex++;
                      }
                  }
                  if (matched) {
                      continue;
                  }
                  return fail("unmatched `" + String.fromCharCode(cc) + "`", currentChunkStartIndex);
              case 47: // /, check for comment
                  if (parenLevel || (chunkerCurrentIndex == len - 1)) {
                      continue;
                  }
                  cc2 = input.charCodeAt(chunkerCurrentIndex + 1);
                  if (cc2 == 47) {
                      // //, find lnfeed
                      for (chunkerCurrentIndex = chunkerCurrentIndex + 2; chunkerCurrentIndex < len; chunkerCurrentIndex++) {
                          cc2 = input.charCodeAt(chunkerCurrentIndex);
                          if ((cc2 <= 13) && ((cc2 == 10) || (cc2 == 13))) {
                              break;
                          }
                      }
                  }
                  else if (cc2 == 42) {
                      // /*, find */
                      lastMultiComment = currentChunkStartIndex = chunkerCurrentIndex;
                      for (chunkerCurrentIndex = chunkerCurrentIndex + 2; chunkerCurrentIndex < len - 1; chunkerCurrentIndex++) {
                          cc2 = input.charCodeAt(chunkerCurrentIndex);
                          if (cc2 == 125) {
                              lastMultiCommentEndBrace = chunkerCurrentIndex;
                          }
                          if (cc2 != 42) {
                              continue;
                          }
                          if (input.charCodeAt(chunkerCurrentIndex + 1) == 47) {
                              break;
                          }
                      }
                      if (chunkerCurrentIndex == len - 1) {
                          return fail('missing closing `*/`', currentChunkStartIndex);
                      }
                      chunkerCurrentIndex++;
                  }
                  continue;
              case 42: // *, check for unmatched */
                  if ((chunkerCurrentIndex < len - 1) && (input.charCodeAt(chunkerCurrentIndex + 1) == 47)) {
                      return fail('unmatched `/*`', chunkerCurrentIndex);
                  }
                  continue;
          }
      }
      if (level !== 0) {
          if ((lastMultiComment > lastOpening) && (lastMultiCommentEndBrace > lastMultiComment)) {
              return fail('missing closing `}` or `*/`', lastOpening);
          }
          else {
              return fail('missing closing `}`', lastOpening);
          }
      }
      else if (parenLevel !== 0) {
          return fail('missing closing `)`', lastOpeningParen);
      }
      emitChunk(true);
      return chunks;
  });

  var getParserInput = (function () {
      var // Less input string
      input;
      var // current chunk
      j;
      var // holds state for backtracking
      saveStack = [];
      var // furthest index the parser has gone to
      furthest;
      var // if this is furthest we got to, this is the probably cause
      furthestPossibleErrorMessage;
      var // chunkified input
      chunks;
      var // current chunk
      current;
      var // index of current chunk, in `input`
      currentPos;
      var parserInput = {};
      var CHARCODE_SPACE = 32;
      var CHARCODE_TAB = 9;
      var CHARCODE_LF = 10;
      var CHARCODE_CR = 13;
      var CHARCODE_PLUS = 43;
      var CHARCODE_COMMA = 44;
      var CHARCODE_FORWARD_SLASH = 47;
      var CHARCODE_9 = 57;
      function skipWhitespace(length) {
          var oldi = parserInput.i;
          var oldj = j;
          var curr = parserInput.i - currentPos;
          var endIndex = parserInput.i + current.length - curr;
          var mem = (parserInput.i += length);
          var inp = input;
          var c;
          var nextChar;
          var comment;
          for (; parserInput.i < endIndex; parserInput.i++) {
              c = inp.charCodeAt(parserInput.i);
              if (parserInput.autoCommentAbsorb && c === CHARCODE_FORWARD_SLASH) {
                  nextChar = inp.charAt(parserInput.i + 1);
                  if (nextChar === '/') {
                      comment = { index: parserInput.i, isLineComment: true };
                      var nextNewLine = inp.indexOf('\n', parserInput.i + 2);
                      if (nextNewLine < 0) {
                          nextNewLine = endIndex;
                      }
                      parserInput.i = nextNewLine;
                      comment.text = inp.substr(comment.index, parserInput.i - comment.index);
                      parserInput.commentStore.push(comment);
                      continue;
                  }
                  else if (nextChar === '*') {
                      var nextStarSlash = inp.indexOf('*/', parserInput.i + 2);
                      if (nextStarSlash >= 0) {
                          comment = {
                              index: parserInput.i,
                              text: inp.substr(parserInput.i, nextStarSlash + 2 - parserInput.i),
                              isLineComment: false
                          };
                          parserInput.i += comment.text.length - 1;
                          parserInput.commentStore.push(comment);
                          continue;
                      }
                  }
                  break;
              }
              if ((c !== CHARCODE_SPACE) && (c !== CHARCODE_LF) && (c !== CHARCODE_TAB) && (c !== CHARCODE_CR)) {
                  break;
              }
          }
          current = current.slice(length + parserInput.i - mem + curr);
          currentPos = parserInput.i;
          if (!current.length) {
              if (j < chunks.length - 1) {
                  current = chunks[++j];
                  skipWhitespace(0); // skip space at the beginning of a chunk
                  return true; // things changed
              }
              parserInput.finished = true;
          }
          return oldi !== parserInput.i || oldj !== j;
      }
      parserInput.save = function () {
          currentPos = parserInput.i;
          saveStack.push({ current: current, i: parserInput.i, j: j });
      };
      parserInput.restore = function (possibleErrorMessage) {
          if (parserInput.i > furthest || (parserInput.i === furthest && possibleErrorMessage && !furthestPossibleErrorMessage)) {
              furthest = parserInput.i;
              furthestPossibleErrorMessage = possibleErrorMessage;
          }
          var state = saveStack.pop();
          current = state.current;
          currentPos = parserInput.i = state.i;
          j = state.j;
      };
      parserInput.forget = function () {
          saveStack.pop();
      };
      parserInput.isWhitespace = function (offset) {
          var pos = parserInput.i + (offset || 0);
          var code = input.charCodeAt(pos);
          return (code === CHARCODE_SPACE || code === CHARCODE_CR || code === CHARCODE_TAB || code === CHARCODE_LF);
      };
      // Specialization of $(tok)
      parserInput.$re = function (tok) {
          if (parserInput.i > currentPos) {
              current = current.slice(parserInput.i - currentPos);
              currentPos = parserInput.i;
          }
          var m = tok.exec(current);
          if (!m) {
              return null;
          }
          skipWhitespace(m[0].length);
          if (typeof m === 'string') {
              return m;
          }
          return m.length === 1 ? m[0] : m;
      };
      parserInput.$char = function (tok) {
          if (input.charAt(parserInput.i) !== tok) {
              return null;
          }
          skipWhitespace(1);
          return tok;
      };
      parserInput.$str = function (tok) {
          var tokLength = tok.length;
          // https://jsperf.com/string-startswith/21
          for (var i_1 = 0; i_1 < tokLength; i_1++) {
              if (input.charAt(parserInput.i + i_1) !== tok.charAt(i_1)) {
                  return null;
              }
          }
          skipWhitespace(tokLength);
          return tok;
      };
      parserInput.$quoted = function (loc) {
          var pos = loc || parserInput.i;
          var startChar = input.charAt(pos);
          if (startChar !== '\'' && startChar !== '"') {
              return;
          }
          var length = input.length;
          var currentPosition = pos;
          for (var i_2 = 1; i_2 + currentPosition < length; i_2++) {
              var nextChar = input.charAt(i_2 + currentPosition);
              switch (nextChar) {
                  case '\\':
                      i_2++;
                      continue;
                  case '\r':
                  case '\n':
                      break;
                  case startChar:
                      var str = input.substr(currentPosition, i_2 + 1);
                      if (!loc && loc !== 0) {
                          skipWhitespace(i_2 + 1);
                          return str;
                      }
                      return [startChar, str];
              }
          }
          return null;
      };
      /**
       * Permissive parsing. Ignores everything except matching {} [] () and quotes
       * until matching token (outside of blocks)
       */
      parserInput.$parseUntil = function (tok) {
          var quote = '';
          var returnVal = null;
          var inComment = false;
          var blockDepth = 0;
          var blockStack = [];
          var parseGroups = [];
          var length = input.length;
          var startPos = parserInput.i;
          var lastPos = parserInput.i;
          var i = parserInput.i;
          var loop = true;
          var testChar;
          if (typeof tok === 'string') {
              testChar = function (char) { return char === tok; };
          }
          else {
              testChar = function (char) { return tok.test(char); };
          }
          do {
              var nextChar = input.charAt(i);
              if (blockDepth === 0 && testChar(nextChar)) {
                  returnVal = input.substr(lastPos, i - lastPos);
                  if (returnVal) {
                      parseGroups.push(returnVal);
                  }
                  else {
                      parseGroups.push(' ');
                  }
                  returnVal = parseGroups;
                  skipWhitespace(i - startPos);
                  loop = false;
              }
              else {
                  if (inComment) {
                      if (nextChar === '*' &&
                          input.charAt(i + 1) === '/') {
                          i++;
                          blockDepth--;
                          inComment = false;
                      }
                      i++;
                      continue;
                  }
                  switch (nextChar) {
                      case '\\':
                          i++;
                          nextChar = input.charAt(i);
                          parseGroups.push(input.substr(lastPos, i - lastPos + 1));
                          lastPos = i + 1;
                          break;
                      case '/':
                          if (input.charAt(i + 1) === '*') {
                              i++;
                              inComment = true;
                              blockDepth++;
                          }
                          break;
                      case '\'':
                      case '"':
                          quote = parserInput.$quoted(i);
                          if (quote) {
                              parseGroups.push(input.substr(lastPos, i - lastPos), quote);
                              i += quote[1].length - 1;
                              lastPos = i + 1;
                          }
                          else {
                              skipWhitespace(i - startPos);
                              returnVal = nextChar;
                              loop = false;
                          }
                          break;
                      case '{':
                          blockStack.push('}');
                          blockDepth++;
                          break;
                      case '(':
                          blockStack.push(')');
                          blockDepth++;
                          break;
                      case '[':
                          blockStack.push(']');
                          blockDepth++;
                          break;
                      case '}':
                      case ')':
                      case ']':
                          var expected = blockStack.pop();
                          if (nextChar === expected) {
                              blockDepth--;
                          }
                          else {
                              // move the parser to the error and return expected
                              skipWhitespace(i - startPos);
                              returnVal = expected;
                              loop = false;
                          }
                  }
                  i++;
                  if (i > length) {
                      loop = false;
                  }
              }
          } while (loop);
          return returnVal ? returnVal : null;
      };
      parserInput.autoCommentAbsorb = true;
      parserInput.commentStore = [];
      parserInput.finished = false;
      // Same as $(), but don't change the state of the parser,
      // just return the match.
      parserInput.peek = function (tok) {
          if (typeof tok === 'string') {
              // https://jsperf.com/string-startswith/21
              for (var i_3 = 0; i_3 < tok.length; i_3++) {
                  if (input.charAt(parserInput.i + i_3) !== tok.charAt(i_3)) {
                      return false;
                  }
              }
              return true;
          }
          else {
              return tok.test(current);
          }
      };
      // Specialization of peek()
      // TODO remove or change some currentChar calls to peekChar
      parserInput.peekChar = function (tok) { return input.charAt(parserInput.i) === tok; };
      parserInput.currentChar = function () { return input.charAt(parserInput.i); };
      parserInput.prevChar = function () { return input.charAt(parserInput.i - 1); };
      parserInput.getInput = function () { return input; };
      parserInput.peekNotNumeric = function () {
          var c = input.charCodeAt(parserInput.i);
          // Is the first char of the dimension 0-9, '.', '+' or '-'
          return (c > CHARCODE_9 || c < CHARCODE_PLUS) || c === CHARCODE_FORWARD_SLASH || c === CHARCODE_COMMA;
      };
      parserInput.start = function (str, chunkInput, failFunction) {
          input = str;
          parserInput.i = j = currentPos = furthest = 0;
          // chunking apparently makes things quicker (but my tests indicate
          // it might actually make things slower in node at least)
          // and it is a non-perfect parse - it can't recognise
          // unquoted urls, meaning it can't distinguish comments
          // meaning comments with quotes or {}() in them get 'counted'
          // and then lead to parse errors.
          // In addition if the chunking chunks in the wrong place we might
          // not be able to parse a parser statement in one go
          // this is officially deprecated but can be switched on via an option
          // in the case it causes too much performance issues.
          if (chunkInput) {
              chunks = chunker(str, failFunction);
          }
          else {
              chunks = [str];
          }
          current = chunks[0];
          skipWhitespace(0);
      };
      parserInput.end = function () {
          var message;
          var isFinished = parserInput.i >= input.length;
          if (parserInput.i < furthest) {
              message = furthestPossibleErrorMessage;
              parserInput.i = furthest;
          }
          return {
              isFinished: isFinished,
              furthest: parserInput.i,
              furthestPossibleErrorMessage: message,
              furthestReachedEnd: parserInput.i >= input.length - 1,
              furthestChar: input[parserInput.i]
          };
      };
      return parserInput;
  });

  //
  // less.js - parser
  //
  //    A relatively straight-forward predictive parser.
  //    There is no tokenization/lexing stage, the input is parsed
  //    in one sweep.
  //
  //    To make the parser fast enough to run in the browser, several
  //    optimization had to be made:
  //
  //    - Matching and slicing on a huge input is often cause of slowdowns.
  //      The solution is to chunkify the input into smaller strings.
  //      The chunks are stored in the `chunks` var,
  //      `j` holds the current chunk index, and `currentPos` holds
  //      the index of the current chunk in relation to `input`.
  //      This gives us an almost 4x speed-up.
  //
  //    - In many cases, we don't need to match individual tokens;
  //      for example, if a value doesn't hold any variables, operations
  //      or dynamic references, the parser can effectively 'skip' it,
  //      treating it as a literal.
  //      An example would be '1px solid #000' - which evaluates to itself,
  //      we don't need to know what the individual components are.
  //      The drawback, of course is that you don't get the benefits of
  //      syntax-checking on the CSS. This gives us a 50% speed-up in the parser,
  //      and a smaller speed-up in the code-gen.
  //
  //
  //    Token matching is done with the `$` function, which either takes
  //    a terminal string or regexp, or a non-terminal function to call.
  //    It also takes care of moving all the indices forwards.
  //
  var Parser = function Parser(context, imports, fileInfo) {
      var parsers;
      var parserInput = getParserInput();
      function error(msg, type) {
          throw new LessError({
              index: parserInput.i,
              filename: fileInfo.filename,
              type: type || 'Syntax',
              message: msg
          }, imports);
      }
      function expect(arg, msg) {
          // some older browsers return typeof 'function' for RegExp
          var result = (arg instanceof Function) ? arg.call(parsers) : parserInput.$re(arg);
          if (result) {
              return result;
          }
          error(msg || (typeof arg === 'string'
              ? "expected '" + arg + "' got '" + parserInput.currentChar() + "'"
              : 'unexpected token'));
      }
      // Specialization of expect()
      function expectChar(arg, msg) {
          if (parserInput.$char(arg)) {
              return arg;
          }
          error(msg || "expected '" + arg + "' got '" + parserInput.currentChar() + "'");
      }
      function getDebugInfo(index) {
          var filename = fileInfo.filename;
          return {
              lineNumber: getLocation(index, parserInput.getInput()).line + 1,
              fileName: filename
          };
      }
      /**
       *  Used after initial parsing to create nodes on the fly
       *
       *  @param {String} str          - string to parse
       *  @param {Array}  parseList    - array of parsers to run input through e.g. ["value", "important"]
       *  @param {Number} currentIndex - start number to begin indexing
       *  @param {Object} fileInfo     - fileInfo to attach to created nodes
       */
      function parseNode(str, parseList, currentIndex, fileInfo, callback) {
          var result;
          var returnNodes = [];
          var parser = parserInput;
          try {
              parser.start(str, false, function fail(msg, index) {
                  callback({
                      message: msg,
                      index: index + currentIndex
                  });
              });
              for (var x = 0, p = void 0, i_1; (p = parseList[x]); x++) {
                  i_1 = parser.i;
                  result = parsers[p]();
                  if (result) {
                      try {
                          result._index = i_1 + currentIndex;
                          result._fileInfo = fileInfo;
                      }
                      catch (e) { }
                      returnNodes.push(result);
                  }
                  else {
                      returnNodes.push(null);
                  }
              }
              var endInfo = parser.end();
              if (endInfo.isFinished) {
                  callback(null, returnNodes);
              }
              else {
                  callback(true, null);
              }
          }
          catch (e) {
              throw new LessError({
                  index: e.index + currentIndex,
                  message: e.message
              }, imports, fileInfo.filename);
          }
      }
      //
      // The Parser
      //
      return {
          parserInput: parserInput,
          imports: imports,
          fileInfo: fileInfo,
          parseNode: parseNode,
          //
          // Parse an input string into an abstract syntax tree,
          // @param str A string containing 'less' markup
          // @param callback call `callback` when done.
          // @param [additionalData] An optional map which can contains vars - a map (key, value) of variables to apply
          //
          parse: function (str, callback, additionalData) {
              var root;
              var error = null;
              var globalVars;
              var modifyVars;
              var ignored;
              var preText = '';
              globalVars = (additionalData && additionalData.globalVars) ? Parser.serializeVars(additionalData.globalVars) + "\n" : '';
              modifyVars = (additionalData && additionalData.modifyVars) ? "\n" + Parser.serializeVars(additionalData.modifyVars) : '';
              if (context.pluginManager) {
                  var preProcessors = context.pluginManager.getPreProcessors();
                  for (var i_2 = 0; i_2 < preProcessors.length; i_2++) {
                      str = preProcessors[i_2].process(str, { context: context, imports: imports, fileInfo: fileInfo });
                  }
              }
              if (globalVars || (additionalData && additionalData.banner)) {
                  preText = ((additionalData && additionalData.banner) ? additionalData.banner : '') + globalVars;
                  ignored = imports.contentsIgnoredChars;
                  ignored[fileInfo.filename] = ignored[fileInfo.filename] || 0;
                  ignored[fileInfo.filename] += preText.length;
              }
              str = str.replace(/\r\n?/g, '\n');
              // Remove potential UTF Byte Order Mark
              str = preText + str.replace(/^\uFEFF/, '') + modifyVars;
              imports.contents[fileInfo.filename] = str;
              // Start with the primary rule.
              // The whole syntax tree is held under a Ruleset node,
              // with the `root` property set to true, so no `{}` are
              // output. The callback is called when the input is parsed.
              try {
                  parserInput.start(str, context.chunkInput, function fail(msg, index) {
                      throw new LessError({
                          index: index,
                          type: 'Parse',
                          message: msg,
                          filename: fileInfo.filename
                      }, imports);
                  });
                  tree.Node.prototype.parse = this;
                  root = new tree.Ruleset(null, this.parsers.primary());
                  tree.Node.prototype.rootNode = root;
                  root.root = true;
                  root.firstRoot = true;
                  root.functionRegistry = functionRegistry.inherit();
              }
              catch (e) {
                  return callback(new LessError(e, imports, fileInfo.filename));
              }
              // If `i` is smaller than the `input.length - 1`,
              // it means the parser wasn't able to parse the whole
              // string, so we've got a parsing error.
              //
              // We try to extract a \n delimited string,
              // showing the line where the parse error occurred.
              // We split it up into two parts (the part which parsed,
              // and the part which didn't), so we can color them differently.
              var endInfo = parserInput.end();
              if (!endInfo.isFinished) {
                  var message = endInfo.furthestPossibleErrorMessage;
                  if (!message) {
                      message = 'Unrecognised input';
                      if (endInfo.furthestChar === '}') {
                          message += '. Possibly missing opening \'{\'';
                      }
                      else if (endInfo.furthestChar === ')') {
                          message += '. Possibly missing opening \'(\'';
                      }
                      else if (endInfo.furthestReachedEnd) {
                          message += '. Possibly missing something';
                      }
                  }
                  error = new LessError({
                      type: 'Parse',
                      message: message,
                      index: endInfo.furthest,
                      filename: fileInfo.filename
                  }, imports);
              }
              var finish = function (e) {
                  e = error || e || imports.error;
                  if (e) {
                      if (!(e instanceof LessError)) {
                          e = new LessError(e, imports, fileInfo.filename);
                      }
                      return callback(e);
                  }
                  else {
                      return callback(null, root);
                  }
              };
              if (context.processImports !== false) {
                  new visitors.ImportVisitor(imports, finish)
                      .run(root);
              }
              else {
                  return finish();
              }
          },
          //
          // Here in, the parsing rules/functions
          //
          // The basic structure of the syntax tree generated is as follows:
          //
          //   Ruleset ->  Declaration -> Value -> Expression -> Entity
          //
          // Here's some Less code:
          //
          //    .class {
          //      color: #fff;
          //      border: 1px solid #000;
          //      width: @w + 4px;
          //      > .child {...}
          //    }
          //
          // And here's what the parse tree might look like:
          //
          //     Ruleset (Selector '.class', [
          //         Declaration ("color",  Value ([Expression [Color #fff]]))
          //         Declaration ("border", Value ([Expression [Dimension 1px][Keyword "solid"][Color #000]]))
          //         Declaration ("width",  Value ([Expression [Operation " + " [Variable "@w"][Dimension 4px]]]))
          //         Ruleset (Selector [Element '>', '.child'], [...])
          //     ])
          //
          //  In general, most rules will try to parse a token with the `$re()` function, and if the return
          //  value is truly, will return a new node, of the relevant type. Sometimes, we need to check
          //  first, before parsing, that's when we use `peek()`.
          //
          parsers: parsers = {
              //
              // The `primary` rule is the *entry* and *exit* point of the parser.
              // The rules here can appear at any level of the parse tree.
              //
              // The recursive nature of the grammar is an interplay between the `block`
              // rule, which represents `{ ... }`, the `ruleset` rule, and this `primary` rule,
              // as represented by this simplified grammar:
              //
              //     primary  →  (ruleset | declaration)+
              //     ruleset  →  selector+ block
              //     block    →  '{' primary '}'
              //
              // Only at one point is the primary rule not called from the
              // block rule: at the root level.
              //
              primary: function () {
                  var mixin = this.mixin;
                  var root = [];
                  var node;
                  while (true) {
                      while (true) {
                          node = this.comment();
                          if (!node) {
                              break;
                          }
                          root.push(node);
                      }
                      // always process comments before deciding if finished
                      if (parserInput.finished) {
                          break;
                      }
                      if (parserInput.peek('}')) {
                          break;
                      }
                      node = this.extendRule();
                      if (node) {
                          root = root.concat(node);
                          continue;
                      }
                      node = mixin.definition() || this.declaration() || mixin.call(false, false) ||
                          this.ruleset() || this.variableCall() || this.entities.call() || this.atrule();
                      if (node) {
                          root.push(node);
                      }
                      else {
                          var foundSemiColon = false;
                          while (parserInput.$char(';')) {
                              foundSemiColon = true;
                          }
                          if (!foundSemiColon) {
                              break;
                          }
                      }
                  }
                  return root;
              },
              // comments are collected by the main parsing mechanism and then assigned to nodes
              // where the current structure allows it
              comment: function () {
                  if (parserInput.commentStore.length) {
                      var comment = parserInput.commentStore.shift();
                      return new (tree.Comment)(comment.text, comment.isLineComment, comment.index, fileInfo);
                  }
              },
              //
              // Entities are tokens which can be found inside an Expression
              //
              entities: {
                  mixinLookup: function () {
                      return parsers.mixin.call(true, true);
                  },
                  //
                  // A string, which supports escaping " and '
                  //
                  //     "milky way" 'he\'s the one!'
                  //
                  quoted: function (forceEscaped) {
                      var str;
                      var index = parserInput.i;
                      var isEscaped = false;
                      parserInput.save();
                      if (parserInput.$char('~')) {
                          isEscaped = true;
                      }
                      else if (forceEscaped) {
                          parserInput.restore();
                          return;
                      }
                      str = parserInput.$quoted();
                      if (!str) {
                          parserInput.restore();
                          return;
                      }
                      parserInput.forget();
                      return new (tree.Quoted)(str.charAt(0), str.substr(1, str.length - 2), isEscaped, index, fileInfo);
                  },
                  //
                  // A catch-all word, such as:
                  //
                  //     black border-collapse
                  //
                  keyword: function () {
                      var k = parserInput.$char('%') || parserInput.$re(/^\[?(?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+\]?/);
                      if (k) {
                          return tree.Color.fromKeyword(k) || new (tree.Keyword)(k);
                      }
                  },
                  //
                  // A function call
                  //
                  //     rgb(255, 0, 255)
                  //
                  // The arguments are parsed with the `entities.arguments` parser.
                  //
                  call: function () {
                      var name;
                      var args;
                      var func;
                      var index = parserInput.i;
                      // http://jsperf.com/case-insensitive-regex-vs-strtolower-then-regex/18
                      if (parserInput.peek(/^url\(/i)) {
                          return;
                      }
                      parserInput.save();
                      name = parserInput.$re(/^([\w-]+|%|progid:[\w\.]+)\(/);
                      if (!name) {
                          parserInput.forget();
                          return;
                      }
                      name = name[1];
                      func = this.customFuncCall(name);
                      if (func) {
                          args = func.parse();
                          if (args && func.stop) {
                              parserInput.forget();
                              return args;
                          }
                      }
                      args = this.arguments(args);
                      if (!parserInput.$char(')')) {
                          parserInput.restore('Could not parse call arguments or missing \')\'');
                          return;
                      }
                      parserInput.forget();
                      return new (tree.Call)(name, args, index, fileInfo);
                  },
                  //
                  // Parsing rules for functions with non-standard args, e.g.:
                  //
                  //     boolean(not(2 > 1))
                  //
                  //     This is a quick prototype, to be modified/improved when
                  //     more custom-parsed funcs come (e.g. `selector(...)`)
                  //
                  customFuncCall: function (name) {
                      /* Ideally the table is to be moved out of here for faster perf.,
                         but it's quite tricky since it relies on all these `parsers`
                         and `expect` available only here */
                      return {
                          alpha: f(parsers.ieAlpha, true),
                          boolean: f(condition),
                          'if': f(condition)
                      }[name.toLowerCase()];
                      function f(parse, stop) {
                          return {
                              parse: parse,
                              stop: stop // when true - stop after parse() and return its result,
                              // otherwise continue for plain args
                          };
                      }
                      function condition() {
                          return [expect(parsers.condition, 'expected condition')];
                      }
                  },
                  arguments: function (prevArgs) {
                      var argsComma = prevArgs || [];
                      var argsSemiColon = [];
                      var isSemiColonSeparated;
                      var value;
                      parserInput.save();
                      while (true) {
                          if (prevArgs) {
                              prevArgs = false;
                          }
                          else {
                              value = parsers.detachedRuleset() || this.assignment() || parsers.expression();
                              if (!value) {
                                  break;
                              }
                              if (value.value && value.value.length == 1) {
                                  value = value.value[0];
                              }
                              argsComma.push(value);
                          }
                          if (parserInput.$char(',')) {
                              continue;
                          }
                          if (parserInput.$char(';') || isSemiColonSeparated) {
                              isSemiColonSeparated = true;
                              value = (argsComma.length < 1) ? argsComma[0]
                                  : new tree.Value(argsComma);
                              argsSemiColon.push(value);
                              argsComma = [];
                          }
                      }
                      parserInput.forget();
                      return isSemiColonSeparated ? argsSemiColon : argsComma;
                  },
                  literal: function () {
                      return this.dimension() ||
                          this.color() ||
                          this.quoted() ||
                          this.unicodeDescriptor();
                  },
                  // Assignments are argument entities for calls.
                  // They are present in ie filter properties as shown below.
                  //
                  //     filter: progid:DXImageTransform.Microsoft.Alpha( *opacity=50* )
                  //
                  assignment: function () {
                      var key;
                      var value;
                      parserInput.save();
                      key = parserInput.$re(/^\w+(?=\s?=)/i);
                      if (!key) {
                          parserInput.restore();
                          return;
                      }
                      if (!parserInput.$char('=')) {
                          parserInput.restore();
                          return;
                      }
                      value = parsers.entity();
                      if (value) {
                          parserInput.forget();
                          return new (tree.Assignment)(key, value);
                      }
                      else {
                          parserInput.restore();
                      }
                  },
                  //
                  // Parse url() tokens
                  //
                  // We use a specific rule for urls, because they don't really behave like
                  // standard function calls. The difference is that the argument doesn't have
                  // to be enclosed within a string, so it can't be parsed as an Expression.
                  //
                  url: function () {
                      var value;
                      var index = parserInput.i;
                      parserInput.autoCommentAbsorb = false;
                      if (!parserInput.$str('url(')) {
                          parserInput.autoCommentAbsorb = true;
                          return;
                      }
                      value = this.quoted() || this.variable() || this.property() ||
                          parserInput.$re(/^(?:(?:\\[\(\)'"])|[^\(\)'"])+/) || '';
                      parserInput.autoCommentAbsorb = true;
                      expectChar(')');
                      return new (tree.URL)((value.value != null ||
                          value instanceof tree.Variable ||
                          value instanceof tree.Property) ?
                          value : new (tree.Anonymous)(value, index), index, fileInfo);
                  },
                  //
                  // A Variable entity, such as `@fink`, in
                  //
                  //     width: @fink + 2px
                  //
                  // We use a different parser for variable definitions,
                  // see `parsers.variable`.
                  //
                  variable: function () {
                      var ch;
                      var name;
                      var index = parserInput.i;
                      parserInput.save();
                      if (parserInput.currentChar() === '@' && (name = parserInput.$re(/^@@?[\w-]+/))) {
                          ch = parserInput.currentChar();
                          if (ch === '(' || ch === '[' && !parserInput.prevChar().match(/^\s/)) {
                              // this may be a VariableCall lookup
                              var result = parsers.variableCall(name);
                              if (result) {
                                  parserInput.forget();
                                  return result;
                              }
                          }
                          parserInput.forget();
                          return new (tree.Variable)(name, index, fileInfo);
                      }
                      parserInput.restore();
                  },
                  // A variable entity using the protective {} e.g. @{var}
                  variableCurly: function () {
                      var curly;
                      var index = parserInput.i;
                      if (parserInput.currentChar() === '@' && (curly = parserInput.$re(/^@\{([\w-]+)\}/))) {
                          return new (tree.Variable)("@" + curly[1], index, fileInfo);
                      }
                  },
                  //
                  // A Property accessor, such as `$color`, in
                  //
                  //     background-color: $color
                  //
                  property: function () {
                      var name;
                      var index = parserInput.i;
                      if (parserInput.currentChar() === '$' && (name = parserInput.$re(/^\$[\w-]+/))) {
                          return new (tree.Property)(name, index, fileInfo);
                      }
                  },
                  // A property entity useing the protective {} e.g. ${prop}
                  propertyCurly: function () {
                      var curly;
                      var index = parserInput.i;
                      if (parserInput.currentChar() === '$' && (curly = parserInput.$re(/^\$\{([\w-]+)\}/))) {
                          return new (tree.Property)("$" + curly[1], index, fileInfo);
                      }
                  },
                  //
                  // A Hexadecimal color
                  //
                  //     #4F3C2F
                  //
                  // `rgb` and `hsl` colors are parsed through the `entities.call` parser.
                  //
                  color: function () {
                      var rgb;
                      parserInput.save();
                      if (parserInput.currentChar() === '#' && (rgb = parserInput.$re(/^#([A-Fa-f0-9]{8}|[A-Fa-f0-9]{6}|[A-Fa-f0-9]{3,4})([\w.#\[])?/))) {
                          if (!rgb[2]) {
                              parserInput.forget();
                              return new (tree.Color)(rgb[1], undefined, rgb[0]);
                          }
                      }
                      parserInput.restore();
                  },
                  colorKeyword: function () {
                      parserInput.save();
                      var autoCommentAbsorb = parserInput.autoCommentAbsorb;
                      parserInput.autoCommentAbsorb = false;
                      var k = parserInput.$re(/^[_A-Za-z-][_A-Za-z0-9-]+/);
                      parserInput.autoCommentAbsorb = autoCommentAbsorb;
                      if (!k) {
                          parserInput.forget();
                          return;
                      }
                      parserInput.restore();
                      var color = tree.Color.fromKeyword(k);
                      if (color) {
                          parserInput.$str(k);
                          return color;
                      }
                  },
                  //
                  // A Dimension, that is, a number and a unit
                  //
                  //     0.5em 95%
                  //
                  dimension: function () {
                      if (parserInput.peekNotNumeric()) {
                          return;
                      }
                      var value = parserInput.$re(/^([+-]?\d*\.?\d+)(%|[a-z_]+)?/i);
                      if (value) {
                          return new (tree.Dimension)(value[1], value[2]);
                      }
                  },
                  //
                  // A unicode descriptor, as is used in unicode-range
                  //
                  // U+0??  or U+00A1-00A9
                  //
                  unicodeDescriptor: function () {
                      var ud;
                      ud = parserInput.$re(/^U\+[0-9a-fA-F?]+(\-[0-9a-fA-F?]+)?/);
                      if (ud) {
                          return new (tree.UnicodeDescriptor)(ud[0]);
                      }
                  },
                  //
                  // JavaScript code to be evaluated
                  //
                  //     `window.location.href`
                  //
                  javascript: function () {
                      var js;
                      var index = parserInput.i;
                      parserInput.save();
                      var escape = parserInput.$char('~');
                      var jsQuote = parserInput.$char('`');
                      if (!jsQuote) {
                          parserInput.restore();
                          return;
                      }
                      js = parserInput.$re(/^[^`]*`/);
                      if (js) {
                          parserInput.forget();
                          return new (tree.JavaScript)(js.substr(0, js.length - 1), Boolean(escape), index, fileInfo);
                      }
                      parserInput.restore('invalid javascript definition');
                  }
              },
              //
              // The variable part of a variable definition. Used in the `rule` parser
              //
              //     @fink:
              //
              variable: function () {
                  var name;
                  if (parserInput.currentChar() === '@' && (name = parserInput.$re(/^(@[\w-]+)\s*:/))) {
                      return name[1];
                  }
              },
              //
              // Call a variable value to retrieve a detached ruleset
              // or a value from a detached ruleset's rules.
              //
              //     @fink();
              //     @fink;
              //     color: @fink[@color];
              //
              variableCall: function (parsedName) {
                  var lookups;
                  var i = parserInput.i;
                  var inValue = !!parsedName;
                  var name = parsedName;
                  parserInput.save();
                  if (name || (parserInput.currentChar() === '@'
                      && (name = parserInput.$re(/^(@[\w-]+)(\(\s*\))?/)))) {
                      lookups = this.mixin.ruleLookups();
                      if (!lookups && ((inValue && parserInput.$str('()') !== '()') || (name[2] !== '()'))) {
                          parserInput.restore('Missing \'[...]\' lookup in variable call');
                          return;
                      }
                      if (!inValue) {
                          name = name[1];
                      }
                      var call = new tree.VariableCall(name, i, fileInfo);
                      if (!inValue && parsers.end()) {
                          parserInput.forget();
                          return call;
                      }
                      else {
                          parserInput.forget();
                          return new tree.NamespaceValue(call, lookups, i, fileInfo);
                      }
                  }
                  parserInput.restore();
              },
              //
              // extend syntax - used to extend selectors
              //
              extend: function (isRule) {
                  var elements;
                  var e;
                  var index = parserInput.i;
                  var option;
                  var extendList;
                  var extend;
                  if (!parserInput.$str(isRule ? '&:extend(' : ':extend(')) {
                      return;
                  }
                  do {
                      option = null;
                      elements = null;
                      while (!(option = parserInput.$re(/^(all)(?=\s*(\)|,))/))) {
                          e = this.element();
                          if (!e) {
                              break;
                          }
                          if (elements) {
                              elements.push(e);
                          }
                          else {
                              elements = [e];
                          }
                      }
                      option = option && option[1];
                      if (!elements) {
                          error('Missing target selector for :extend().');
                      }
                      extend = new (tree.Extend)(new (tree.Selector)(elements), option, index, fileInfo);
                      if (extendList) {
                          extendList.push(extend);
                      }
                      else {
                          extendList = [extend];
                      }
                  } while (parserInput.$char(','));
                  expect(/^\)/);
                  if (isRule) {
                      expect(/^;/);
                  }
                  return extendList;
              },
              //
              // extendRule - used in a rule to extend all the parent selectors
              //
              extendRule: function () {
                  return this.extend(true);
              },
              //
              // Mixins
              //
              mixin: {
                  //
                  // A Mixin call, with an optional argument list
                  //
                  //     #mixins > .square(#fff);
                  //     #mixins.square(#fff);
                  //     .rounded(4px, black);
                  //     .button;
                  //
                  // We can lookup / return a value using the lookup syntax:
                  //
                  //     color: #mixin.square(#fff)[@color];
                  //
                  // The `while` loop is there because mixins can be
                  // namespaced, but we only support the child and descendant
                  // selector for now.
                  //
                  call: function (inValue, getLookup) {
                      var s = parserInput.currentChar();
                      var important = false;
                      var lookups;
                      var index = parserInput.i;
                      var elements;
                      var args;
                      var hasParens;
                      if (s !== '.' && s !== '#') {
                          return;
                      }
                      parserInput.save(); // stop us absorbing part of an invalid selector
                      elements = this.elements();
                      if (elements) {
                          if (parserInput.$char('(')) {
                              args = this.args(true).args;
                              expectChar(')');
                              hasParens = true;
                          }
                          if (getLookup !== false) {
                              lookups = this.ruleLookups();
                          }
                          if (getLookup === true && !lookups) {
                              parserInput.restore();
                              return;
                          }
                          if (inValue && !lookups && !hasParens) {
                              // This isn't a valid in-value mixin call
                              parserInput.restore();
                              return;
                          }
                          if (!inValue && parsers.important()) {
                              important = true;
                          }
                          if (inValue || parsers.end()) {
                              parserInput.forget();
                              var mixin = new (tree.mixin.Call)(elements, args, index, fileInfo, !lookups && important);
                              if (lookups) {
                                  return new tree.NamespaceValue(mixin, lookups);
                              }
                              else {
                                  return mixin;
                              }
                          }
                      }
                      parserInput.restore();
                  },
                  /**
                   * Matching elements for mixins
                   * (Start with . or # and can have > )
                   */
                  elements: function () {
                      var elements;
                      var e;
                      var c;
                      var elem;
                      var elemIndex;
                      var re = /^[#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/;
                      while (true) {
                          elemIndex = parserInput.i;
                          e = parserInput.$re(re);
                          if (!e) {
                              break;
                          }
                          elem = new (tree.Element)(c, e, false, elemIndex, fileInfo);
                          if (elements) {
                              elements.push(elem);
                          }
                          else {
                              elements = [elem];
                          }
                          c = parserInput.$char('>');
                      }
                      return elements;
                  },
                  args: function (isCall) {
                      var entities = parsers.entities;
                      var returner = { args: null, variadic: false };
                      var expressions = [];
                      var argsSemiColon = [];
                      var argsComma = [];
                      var isSemiColonSeparated;
                      var expressionContainsNamed;
                      var name;
                      var nameLoop;
                      var value;
                      var arg;
                      var expand;
                      var hasSep = true;
                      parserInput.save();
                      while (true) {
                          if (isCall) {
                              arg = parsers.detachedRuleset() || parsers.expression();
                          }
                          else {
                              parserInput.commentStore.length = 0;
                              if (parserInput.$str('...')) {
                                  returner.variadic = true;
                                  if (parserInput.$char(';') && !isSemiColonSeparated) {
                                      isSemiColonSeparated = true;
                                  }
                                  (isSemiColonSeparated ? argsSemiColon : argsComma)
                                      .push({ variadic: true });
                                  break;
                              }
                              arg = entities.variable() || entities.property() || entities.literal() || entities.keyword() || this.call(true);
                          }
                          if (!arg || !hasSep) {
                              break;
                          }
                          nameLoop = null;
                          if (arg.throwAwayComments) {
                              arg.throwAwayComments();
                          }
                          value = arg;
                          var val = null;
                          if (isCall) {
                              // Variable
                              if (arg.value && arg.value.length == 1) {
                                  val = arg.value[0];
                              }
                          }
                          else {
                              val = arg;
                          }
                          if (val && (val instanceof tree.Variable || val instanceof tree.Property)) {
                              if (parserInput.$char(':')) {
                                  if (expressions.length > 0) {
                                      if (isSemiColonSeparated) {
                                          error('Cannot mix ; and , as delimiter types');
                                      }
                                      expressionContainsNamed = true;
                                  }
                                  value = parsers.detachedRuleset() || parsers.expression();
                                  if (!value) {
                                      if (isCall) {
                                          error('could not understand value for named argument');
                                      }
                                      else {
                                          parserInput.restore();
                                          returner.args = [];
                                          return returner;
                                      }
                                  }
                                  nameLoop = (name = val.name);
                              }
                              else if (parserInput.$str('...')) {
                                  if (!isCall) {
                                      returner.variadic = true;
                                      if (parserInput.$char(';') && !isSemiColonSeparated) {
                                          isSemiColonSeparated = true;
                                      }
                                      (isSemiColonSeparated ? argsSemiColon : argsComma)
                                          .push({ name: arg.name, variadic: true });
                                      break;
                                  }
                                  else {
                                      expand = true;
                                  }
                              }
                              else if (!isCall) {
                                  name = nameLoop = val.name;
                                  value = null;
                              }
                          }
                          if (value) {
                              expressions.push(value);
                          }
                          argsComma.push({ name: nameLoop, value: value, expand: expand });
                          if (parserInput.$char(',')) {
                              hasSep = true;
                              continue;
                          }
                          hasSep = parserInput.$char(';') === ';';
                          if (hasSep || isSemiColonSeparated) {
                              if (expressionContainsNamed) {
                                  error('Cannot mix ; and , as delimiter types');
                              }
                              isSemiColonSeparated = true;
                              if (expressions.length > 1) {
                                  value = new (tree.Value)(expressions);
                              }
                              argsSemiColon.push({ name: name, value: value, expand: expand });
                              name = null;
                              expressions = [];
                              expressionContainsNamed = false;
                          }
                      }
                      parserInput.forget();
                      returner.args = isSemiColonSeparated ? argsSemiColon : argsComma;
                      return returner;
                  },
                  //
                  // A Mixin definition, with a list of parameters
                  //
                  //     .rounded (@radius: 2px, @color) {
                  //        ...
                  //     }
                  //
                  // Until we have a finer grained state-machine, we have to
                  // do a look-ahead, to make sure we don't have a mixin call.
                  // See the `rule` function for more information.
                  //
                  // We start by matching `.rounded (`, and then proceed on to
                  // the argument list, which has optional default values.
                  // We store the parameters in `params`, with a `value` key,
                  // if there is a value, such as in the case of `@radius`.
                  //
                  // Once we've got our params list, and a closing `)`, we parse
                  // the `{...}` block.
                  //
                  definition: function () {
                      var name;
                      var params = [];
                      var match;
                      var ruleset;
                      var cond;
                      var variadic = false;
                      if ((parserInput.currentChar() !== '.' && parserInput.currentChar() !== '#') ||
                          parserInput.peek(/^[^{]*\}/)) {
                          return;
                      }
                      parserInput.save();
                      match = parserInput.$re(/^([#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+)\s*\(/);
                      if (match) {
                          name = match[1];
                          var argInfo = this.args(false);
                          params = argInfo.args;
                          variadic = argInfo.variadic;
                          // .mixincall("@{a}");
                          // looks a bit like a mixin definition..
                          // also
                          // .mixincall(@a: {rule: set;});
                          // so we have to be nice and restore
                          if (!parserInput.$char(')')) {
                              parserInput.restore('Missing closing \')\'');
                              return;
                          }
                          parserInput.commentStore.length = 0;
                          if (parserInput.$str('when')) { // Guard
                              cond = expect(parsers.conditions, 'expected condition');
                          }
                          ruleset = parsers.block();
                          if (ruleset) {
                              parserInput.forget();
                              return new (tree.mixin.Definition)(name, params, ruleset, cond, variadic);
                          }
                          else {
                              parserInput.restore();
                          }
                      }
                      else {
                          parserInput.restore();
                      }
                  },
                  ruleLookups: function () {
                      var rule;
                      var lookups = [];
                      if (parserInput.currentChar() !== '[') {
                          return;
                      }
                      while (true) {
                          parserInput.save();
                          rule = this.lookupValue();
                          if (!rule && rule !== '') {
                              parserInput.restore();
                              break;
                          }
                          lookups.push(rule);
                          parserInput.forget();
                      }
                      if (lookups.length > 0) {
                          return lookups;
                      }
                  },
                  lookupValue: function () {
                      parserInput.save();
                      if (!parserInput.$char('[')) {
                          parserInput.restore();
                          return;
                      }
                      var name = parserInput.$re(/^(?:[@$]{0,2})[_a-zA-Z0-9-]*/);
                      if (!parserInput.$char(']')) {
                          parserInput.restore();
                          return;
                      }
                      if (name || name === '') {
                          parserInput.forget();
                          return name;
                      }
                      parserInput.restore();
                  }
              },
              //
              // Entities are the smallest recognized token,
              // and can be found inside a rule's value.
              //
              entity: function () {
                  var entities = this.entities;
                  return this.comment() || entities.literal() || entities.variable() || entities.url() ||
                      entities.property() || entities.call() || entities.keyword() || this.mixin.call(true) ||
                      entities.javascript();
              },
              //
              // A Declaration terminator. Note that we use `peek()` to check for '}',
              // because the `block` rule will be expecting it, but we still need to make sure
              // it's there, if ';' was omitted.
              //
              end: function () {
                  return parserInput.$char(';') || parserInput.peek('}');
              },
              //
              // IE's alpha function
              //
              //     alpha(opacity=88)
              //
              ieAlpha: function () {
                  var value;
                  // http://jsperf.com/case-insensitive-regex-vs-strtolower-then-regex/18
                  if (!parserInput.$re(/^opacity=/i)) {
                      return;
                  }
                  value = parserInput.$re(/^\d+/);
                  if (!value) {
                      value = expect(parsers.entities.variable, 'Could not parse alpha');
                      value = "@{" + value.name.slice(1) + "}";
                  }
                  expectChar(')');
                  return new tree.Quoted('', "alpha(opacity=" + value + ")");
              },
              //
              // A Selector Element
              //
              //     div
              //     + h1
              //     #socks
              //     input[type="text"]
              //
              // Elements are the building blocks for Selectors,
              // they are made out of a `Combinator` (see combinator rule),
              // and an element name, such as a tag a class, or `*`.
              //
              element: function () {
                  var e;
                  var c;
                  var v;
                  var index = parserInput.i;
                  c = this.combinator();
                  e = parserInput.$re(/^(?:\d+\.\d+|\d+)%/) ||
                      parserInput.$re(/^(?:[.#]?|:*)(?:[\w-]|[^\x00-\x9f]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/) ||
                      parserInput.$char('*') || parserInput.$char('&') || this.attribute() ||
                      parserInput.$re(/^\([^&()@]+\)/) || parserInput.$re(/^[\.#:](?=@)/) ||
                      this.entities.variableCurly();
                  if (!e) {
                      parserInput.save();
                      if (parserInput.$char('(')) {
                          if ((v = this.selector(false)) && parserInput.$char(')')) {
                              e = new (tree.Paren)(v);
                              parserInput.forget();
                          }
                          else {
                              parserInput.restore('Missing closing \')\'');
                          }
                      }
                      else {
                          parserInput.forget();
                      }
                  }
                  if (e) {
                      return new (tree.Element)(c, e, e instanceof tree.Variable, index, fileInfo);
                  }
              },
              //
              // Combinators combine elements together, in a Selector.
              //
              // Because our parser isn't white-space sensitive, special care
              // has to be taken, when parsing the descendant combinator, ` `,
              // as it's an empty space. We have to check the previous character
              // in the input, to see if it's a ` ` character. More info on how
              // we deal with this in *combinator.js*.
              //
              combinator: function () {
                  var c = parserInput.currentChar();
                  if (c === '/') {
                      parserInput.save();
                      var slashedCombinator = parserInput.$re(/^\/[a-z]+\//i);
                      if (slashedCombinator) {
                          parserInput.forget();
                          return new (tree.Combinator)(slashedCombinator);
                      }
                      parserInput.restore();
                  }
                  if (c === '>' || c === '+' || c === '~' || c === '|' || c === '^') {
                      parserInput.i++;
                      if (c === '^' && parserInput.currentChar() === '^') {
                          c = '^^';
                          parserInput.i++;
                      }
                      while (parserInput.isWhitespace()) {
                          parserInput.i++;
                      }
                      return new (tree.Combinator)(c);
                  }
                  else if (parserInput.isWhitespace(-1)) {
                      return new (tree.Combinator)(' ');
                  }
                  else {
                      return new (tree.Combinator)(null);
                  }
              },
              //
              // A CSS Selector
              // with less extensions e.g. the ability to extend and guard
              //
              //     .class > div + h1
              //     li a:hover
              //
              // Selectors are made out of one or more Elements, see above.
              //
              selector: function (isLess) {
                  var index = parserInput.i;
                  var elements;
                  var extendList;
                  var c;
                  var e;
                  var allExtends;
                  var when;
                  var condition;
                  isLess = isLess !== false;
                  while ((isLess && (extendList = this.extend())) || (isLess && (when = parserInput.$str('when'))) || (e = this.element())) {
                      if (when) {
                          condition = expect(this.conditions, 'expected condition');
                      }
                      else if (condition) {
                          error('CSS guard can only be used at the end of selector');
                      }
                      else if (extendList) {
                          if (allExtends) {
                              allExtends = allExtends.concat(extendList);
                          }
                          else {
                              allExtends = extendList;
                          }
                      }
                      else {
                          if (allExtends) {
                              error('Extend can only be used at the end of selector');
                          }
                          c = parserInput.currentChar();
                          if (elements) {
                              elements.push(e);
                          }
                          else {
                              elements = [e];
                          }
                          e = null;
                      }
                      if (c === '{' || c === '}' || c === ';' || c === ',' || c === ')') {
                          break;
                      }
                  }
                  if (elements) {
                      return new (tree.Selector)(elements, allExtends, condition, index, fileInfo);
                  }
                  if (allExtends) {
                      error('Extend must be used to extend a selector, it cannot be used on its own');
                  }
              },
              selectors: function () {
                  var s;
                  var selectors;
                  while (true) {
                      s = this.selector();
                      if (!s) {
                          break;
                      }
                      if (selectors) {
                          selectors.push(s);
                      }
                      else {
                          selectors = [s];
                      }
                      parserInput.commentStore.length = 0;
                      if (s.condition && selectors.length > 1) {
                          error("Guards are only currently allowed on a single selector.");
                      }
                      if (!parserInput.$char(',')) {
                          break;
                      }
                      if (s.condition) {
                          error("Guards are only currently allowed on a single selector.");
                      }
                      parserInput.commentStore.length = 0;
                  }
                  return selectors;
              },
              attribute: function () {
                  if (!parserInput.$char('[')) {
                      return;
                  }
                  var entities = this.entities;
                  var key;
                  var val;
                  var op;
                  if (!(key = entities.variableCurly())) {
                      key = expect(/^(?:[_A-Za-z0-9-\*]*\|)?(?:[_A-Za-z0-9-]|\\.)+/);
                  }
                  op = parserInput.$re(/^[|~*$^]?=/);
                  if (op) {
                      val = entities.quoted() || parserInput.$re(/^[0-9]+%/) || parserInput.$re(/^[\w-]+/) || entities.variableCurly();
                  }
                  expectChar(']');
                  return new (tree.Attribute)(key, op, val);
              },
              //
              // The `block` rule is used by `ruleset` and `mixin.definition`.
              // It's a wrapper around the `primary` rule, with added `{}`.
              //
              block: function () {
                  var content;
                  if (parserInput.$char('{') && (content = this.primary()) && parserInput.$char('}')) {
                      return content;
                  }
              },
              blockRuleset: function () {
                  var block = this.block();
                  if (block) {
                      block = new tree.Ruleset(null, block);
                  }
                  return block;
              },
              detachedRuleset: function () {
                  var argInfo;
                  var params;
                  var variadic;
                  parserInput.save();
                  if (parserInput.$re(/^[.#]\(/)) {
                      /**
                       * DR args currently only implemented for each() function, and not
                       * yet settable as `@dr: #(@arg) {}`
                       * This should be done when DRs are merged with mixins.
                       * See: https://github.com/less/less-meta/issues/16
                       */
                      argInfo = this.mixin.args(false);
                      params = argInfo.args;
                      variadic = argInfo.variadic;
                      if (!parserInput.$char(')')) {
                          parserInput.restore();
                          return;
                      }
                  }
                  var blockRuleset = this.blockRuleset();
                  if (blockRuleset) {
                      parserInput.forget();
                      if (params) {
                          return new tree.mixin.Definition(null, params, blockRuleset, null, variadic);
                      }
                      return new tree.DetachedRuleset(blockRuleset);
                  }
                  parserInput.restore();
              },
              //
              // div, .class, body > p {...}
              //
              ruleset: function () {
                  var selectors;
                  var rules;
                  var debugInfo;
                  parserInput.save();
                  if (context.dumpLineNumbers) {
                      debugInfo = getDebugInfo(parserInput.i);
                  }
                  selectors = this.selectors();
                  if (selectors && (rules = this.block())) {
                      parserInput.forget();
                      var ruleset = new (tree.Ruleset)(selectors, rules, context.strictImports);
                      if (context.dumpLineNumbers) {
                          ruleset.debugInfo = debugInfo;
                      }
                      return ruleset;
                  }
                  else {
                      parserInput.restore();
                  }
              },
              declaration: function () {
                  var name;
                  var value;
                  var index = parserInput.i;
                  var hasDR;
                  var c = parserInput.currentChar();
                  var important;
                  var merge;
                  var isVariable;
                  if (c === '.' || c === '#' || c === '&' || c === ':') {
                      return;
                  }
                  parserInput.save();
                  name = this.variable() || this.ruleProperty();
                  if (name) {
                      isVariable = typeof name === 'string';
                      if (isVariable) {
                          value = this.detachedRuleset();
                          if (value) {
                              hasDR = true;
                          }
                      }
                      parserInput.commentStore.length = 0;
                      if (!value) {
                          // a name returned by this.ruleProperty() is always an array of the form:
                          // [string-1, ..., string-n, ""] or [string-1, ..., string-n, "+"]
                          // where each item is a tree.Keyword or tree.Variable
                          merge = !isVariable && name.length > 1 && name.pop().value;
                          // Custom property values get permissive parsing
                          if (name[0].value && name[0].value.slice(0, 2) === '--') {
                              value = this.permissiveValue();
                          }
                          // Try to store values as anonymous
                          // If we need the value later we'll re-parse it in ruleset.parseValue
                          else {
                              value = this.anonymousValue();
                          }
                          if (value) {
                              parserInput.forget();
                              // anonymous values absorb the end ';' which is required for them to work
                              return new (tree.Declaration)(name, value, false, merge, index, fileInfo);
                          }
                          if (!value) {
                              value = this.value();
                          }
                          if (value) {
                              important = this.important();
                          }
                          else if (isVariable) {
                              // As a last resort, try permissiveValue
                              value = this.permissiveValue();
                          }
                      }
                      if (value && (this.end() || hasDR)) {
                          parserInput.forget();
                          return new (tree.Declaration)(name, value, important, merge, index, fileInfo);
                      }
                      else {
                          parserInput.restore();
                      }
                  }
                  else {
                      parserInput.restore();
                  }
              },
              anonymousValue: function () {
                  var index = parserInput.i;
                  var match = parserInput.$re(/^([^.#@\$+\/'"*`(;{}-]*);/);
                  if (match) {
                      return new (tree.Anonymous)(match[1], index);
                  }
              },
              /**
               * Used for custom properties, at-rules, and variables (as fallback)
               * Parses almost anything inside of {} [] () "" blocks
               * until it reaches outer-most tokens.
               *
               * First, it will try to parse comments and entities to reach
               * the end. This is mostly like the Expression parser except no
               * math is allowed.
               */
              permissiveValue: function (untilTokens) {
                  var i;
                  var e;
                  var done;
                  var value;
                  var tok = untilTokens || ';';
                  var index = parserInput.i;
                  var result = [];
                  function testCurrentChar() {
                      var char = parserInput.currentChar();
                      if (typeof tok === 'string') {
                          return char === tok;
                      }
                      else {
                          return tok.test(char);
                      }
                  }
                  if (testCurrentChar()) {
                      return;
                  }
                  value = [];
                  do {
                      e = this.comment();
                      if (e) {
                          value.push(e);
                          continue;
                      }
                      e = this.entity();
                      if (e) {
                          value.push(e);
                      }
                  } while (e);
                  done = testCurrentChar();
                  if (value.length > 0) {
                      value = new (tree.Expression)(value);
                      if (done) {
                          return value;
                      }
                      else {
                          result.push(value);
                      }
                      // Preserve space before $parseUntil as it will not
                      if (parserInput.prevChar() === ' ') {
                          result.push(new tree.Anonymous(' ', index));
                      }
                  }
                  parserInput.save();
                  value = parserInput.$parseUntil(tok);
                  if (value) {
                      if (typeof value === 'string') {
                          error("Expected '" + value + "'", 'Parse');
                      }
                      if (value.length === 1 && value[0] === ' ') {
                          parserInput.forget();
                          return new tree.Anonymous('', index);
                      }
                      var item = void 0;
                      for (i = 0; i < value.length; i++) {
                          item = value[i];
                          if (Array.isArray(item)) {
                              // Treat actual quotes as normal quoted values
                              result.push(new tree.Quoted(item[0], item[1], true, index, fileInfo));
                          }
                          else {
                              if (i === value.length - 1) {
                                  item = item.trim();
                              }
                              // Treat like quoted values, but replace vars like unquoted expressions
                              var quote = new tree.Quoted('\'', item, true, index, fileInfo);
                              quote.variableRegex = /@([\w-]+)/g;
                              quote.propRegex = /\$([\w-]+)/g;
                              result.push(quote);
                          }
                      }
                      parserInput.forget();
                      return new tree.Expression(result, true);
                  }
                  parserInput.restore();
              },
              //
              // An @import atrule
              //
              //     @import "lib";
              //
              // Depending on our environment, importing is done differently:
              // In the browser, it's an XHR request, in Node, it would be a
              // file-system operation. The function used for importing is
              // stored in `import`, which we pass to the Import constructor.
              //
              'import': function () {
                  var path;
                  var features;
                  var index = parserInput.i;
                  var dir = parserInput.$re(/^@import?\s+/);
                  if (dir) {
                      var options_1 = (dir ? this.importOptions() : null) || {};
                      if ((path = this.entities.quoted() || this.entities.url())) {
                          features = this.mediaFeatures();
                          if (!parserInput.$char(';')) {
                              parserInput.i = index;
                              error('missing semi-colon or unrecognised media features on import');
                          }
                          features = features && new (tree.Value)(features);
                          return new (tree.Import)(path, features, options_1, index, fileInfo);
                      }
                      else {
                          parserInput.i = index;
                          error('malformed import statement');
                      }
                  }
              },
              importOptions: function () {
                  var o;
                  var options = {};
                  var optionName;
                  var value;
                  // list of options, surrounded by parens
                  if (!parserInput.$char('(')) {
                      return null;
                  }
                  do {
                      o = this.importOption();
                      if (o) {
                          optionName = o;
                          value = true;
                          switch (optionName) {
                              case 'css':
                                  optionName = 'less';
                                  value = false;
                                  break;
                              case 'once':
                                  optionName = 'multiple';
                                  value = false;
                                  break;
                          }
                          options[optionName] = value;
                          if (!parserInput.$char(',')) {
                              break;
                          }
                      }
                  } while (o);
                  expectChar(')');
                  return options;
              },
              importOption: function () {
                  var opt = parserInput.$re(/^(less|css|multiple|once|inline|reference|optional)/);
                  if (opt) {
                      return opt[1];
                  }
              },
              mediaFeature: function () {
                  var entities = this.entities;
                  var nodes = [];
                  var e;
                  var p;
                  parserInput.save();
                  do {
                      e = entities.keyword() || entities.variable() || entities.mixinLookup();
                      if (e) {
                          nodes.push(e);
                      }
                      else if (parserInput.$char('(')) {
                          p = this.property();
                          e = this.value();
                          if (parserInput.$char(')')) {
                              if (p && e) {
                                  nodes.push(new (tree.Paren)(new (tree.Declaration)(p, e, null, null, parserInput.i, fileInfo, true)));
                              }
                              else if (e) {
                                  nodes.push(new (tree.Paren)(e));
                              }
                              else {
                                  error('badly formed media feature definition');
                              }
                          }
                          else {
                              error('Missing closing \')\'', 'Parse');
                          }
                      }
                  } while (e);
                  parserInput.forget();
                  if (nodes.length > 0) {
                      return new (tree.Expression)(nodes);
                  }
              },
              mediaFeatures: function () {
                  var entities = this.entities;
                  var features = [];
                  var e;
                  do {
                      e = this.mediaFeature();
                      if (e) {
                          features.push(e);
                          if (!parserInput.$char(',')) {
                              break;
                          }
                      }
                      else {
                          e = entities.variable() || entities.mixinLookup();
                          if (e) {
                              features.push(e);
                              if (!parserInput.$char(',')) {
                                  break;
                              }
                          }
                      }
                  } while (e);
                  return features.length > 0 ? features : null;
              },
              media: function () {
                  var features;
                  var rules;
                  var media;
                  var debugInfo;
                  var index = parserInput.i;
                  if (context.dumpLineNumbers) {
                      debugInfo = getDebugInfo(index);
                  }
                  parserInput.save();
                  if (parserInput.$str('@media')) {
                      features = this.mediaFeatures();
                      rules = this.block();
                      if (!rules) {
                          error('media definitions require block statements after any features');
                      }
                      parserInput.forget();
                      media = new (tree.Media)(rules, features, index, fileInfo);
                      if (context.dumpLineNumbers) {
                          media.debugInfo = debugInfo;
                      }
                      return media;
                  }
                  parserInput.restore();
              },
              //
              // A @plugin directive, used to import plugins dynamically.
              //
              //     @plugin (args) "lib";
              //
              plugin: function () {
                  var path;
                  var args;
                  var options;
                  var index = parserInput.i;
                  var dir = parserInput.$re(/^@plugin?\s+/);
                  if (dir) {
                      args = this.pluginArgs();
                      if (args) {
                          options = {
                              pluginArgs: args,
                              isPlugin: true
                          };
                      }
                      else {
                          options = { isPlugin: true };
                      }
                      if ((path = this.entities.quoted() || this.entities.url())) {
                          if (!parserInput.$char(';')) {
                              parserInput.i = index;
                              error('missing semi-colon on @plugin');
                          }
                          return new (tree.Import)(path, null, options, index, fileInfo);
                      }
                      else {
                          parserInput.i = index;
                          error('malformed @plugin statement');
                      }
                  }
              },
              pluginArgs: function () {
                  // list of options, surrounded by parens
                  parserInput.save();
                  if (!parserInput.$char('(')) {
                      parserInput.restore();
                      return null;
                  }
                  var args = parserInput.$re(/^\s*([^\);]+)\)\s*/);
                  if (args[1]) {
                      parserInput.forget();
                      return args[1].trim();
                  }
                  else {
                      parserInput.restore();
                      return null;
                  }
              },
              //
              // A CSS AtRule
              //
              //     @charset "utf-8";
              //
              atrule: function () {
                  var index = parserInput.i;
                  var name;
                  var value;
                  var rules;
                  var nonVendorSpecificName;
                  var hasIdentifier;
                  var hasExpression;
                  var hasUnknown;
                  var hasBlock = true;
                  var isRooted = true;
                  if (parserInput.currentChar() !== '@') {
                      return;
                  }
                  value = this['import']() || this.plugin() || this.media();
                  if (value) {
                      return value;
                  }
                  parserInput.save();
                  name = parserInput.$re(/^@[a-z-]+/);
                  if (!name) {
                      return;
                  }
                  nonVendorSpecificName = name;
                  if (name.charAt(1) == '-' && name.indexOf('-', 2) > 0) {
                      nonVendorSpecificName = "@" + name.slice(name.indexOf('-', 2) + 1);
                  }
                  switch (nonVendorSpecificName) {
                      case '@charset':
                          hasIdentifier = true;
                          hasBlock = false;
                          break;
                      case '@namespace':
                          hasExpression = true;
                          hasBlock = false;
                          break;
                      case '@keyframes':
                      case '@counter-style':
                          hasIdentifier = true;
                          break;
                      case '@document':
                      case '@supports':
                          hasUnknown = true;
                          isRooted = false;
                          break;
                      default:
                          hasUnknown = true;
                          break;
                  }
                  parserInput.commentStore.length = 0;
                  if (hasIdentifier) {
                      value = this.entity();
                      if (!value) {
                          error("expected " + name + " identifier");
                      }
                  }
                  else if (hasExpression) {
                      value = this.expression();
                      if (!value) {
                          error("expected " + name + " expression");
                      }
                  }
                  else if (hasUnknown) {
                      value = this.permissiveValue(/^[{;]/);
                      hasBlock = (parserInput.currentChar() === '{');
                      if (!value) {
                          if (!hasBlock && parserInput.currentChar() !== ';') {
                              error(name + " rule is missing block or ending semi-colon");
                          }
                      }
                      else if (!value.value) {
                          value = null;
                      }
                  }
                  if (hasBlock) {
                      rules = this.blockRuleset();
                  }
                  if (rules || (!hasBlock && value && parserInput.$char(';'))) {
                      parserInput.forget();
                      return new (tree.AtRule)(name, value, rules, index, fileInfo, context.dumpLineNumbers ? getDebugInfo(index) : null, isRooted);
                  }
                  parserInput.restore('at-rule options not recognised');
              },
              //
              // A Value is a comma-delimited list of Expressions
              //
              //     font-family: Baskerville, Georgia, serif;
              //
              // In a Rule, a Value represents everything after the `:`,
              // and before the `;`.
              //
              value: function () {
                  var e;
                  var expressions = [];
                  var index = parserInput.i;
                  do {
                      e = this.expression();
                      if (e) {
                          expressions.push(e);
                          if (!parserInput.$char(',')) {
                              break;
                          }
                      }
                  } while (e);
                  if (expressions.length > 0) {
                      return new (tree.Value)(expressions, index);
                  }
              },
              important: function () {
                  if (parserInput.currentChar() === '!') {
                      return parserInput.$re(/^! *important/);
                  }
              },
              sub: function () {
                  var a;
                  var e;
                  parserInput.save();
                  if (parserInput.$char('(')) {
                      a = this.addition();
                      if (a && parserInput.$char(')')) {
                          parserInput.forget();
                          e = new (tree.Expression)([a]);
                          e.parens = true;
                          return e;
                      }
                      parserInput.restore('Expected \')\'');
                      return;
                  }
                  parserInput.restore();
              },
              multiplication: function () {
                  var m;
                  var a;
                  var op;
                  var operation;
                  var isSpaced;
                  m = this.operand();
                  if (m) {
                      isSpaced = parserInput.isWhitespace(-1);
                      while (true) {
                          if (parserInput.peek(/^\/[*\/]/)) {
                              break;
                          }
                          parserInput.save();
                          op = parserInput.$char('/') || parserInput.$char('*') || parserInput.$str('./');
                          if (!op) {
                              parserInput.forget();
                              break;
                          }
                          a = this.operand();
                          if (!a) {
                              parserInput.restore();
                              break;
                          }
                          parserInput.forget();
                          m.parensInOp = true;
                          a.parensInOp = true;
                          operation = new (tree.Operation)(op, [operation || m, a], isSpaced);
                          isSpaced = parserInput.isWhitespace(-1);
                      }
                      return operation || m;
                  }
              },
              addition: function () {
                  var m;
                  var a;
                  var op;
                  var operation;
                  var isSpaced;
                  m = this.multiplication();
                  if (m) {
                      isSpaced = parserInput.isWhitespace(-1);
                      while (true) {
                          op = parserInput.$re(/^[-+]\s+/) || (!isSpaced && (parserInput.$char('+') || parserInput.$char('-')));
                          if (!op) {
                              break;
                          }
                          a = this.multiplication();
                          if (!a) {
                              break;
                          }
                          m.parensInOp = true;
                          a.parensInOp = true;
                          operation = new (tree.Operation)(op, [operation || m, a], isSpaced);
                          isSpaced = parserInput.isWhitespace(-1);
                      }
                      return operation || m;
                  }
              },
              conditions: function () {
                  var a;
                  var b;
                  var index = parserInput.i;
                  var condition;
                  a = this.condition(true);
                  if (a) {
                      while (true) {
                          if (!parserInput.peek(/^,\s*(not\s*)?\(/) || !parserInput.$char(',')) {
                              break;
                          }
                          b = this.condition(true);
                          if (!b) {
                              break;
                          }
                          condition = new (tree.Condition)('or', condition || a, b, index);
                      }
                      return condition || a;
                  }
              },
              condition: function (needsParens) {
                  var result;
                  var logical;
                  var next;
                  function or() {
                      return parserInput.$str('or');
                  }
                  result = this.conditionAnd(needsParens);
                  if (!result) {
                      return;
                  }
                  logical = or();
                  if (logical) {
                      next = this.condition(needsParens);
                      if (next) {
                          result = new (tree.Condition)(logical, result, next);
                      }
                      else {
                          return;
                      }
                  }
                  return result;
              },
              conditionAnd: function (needsParens) {
                  var result;
                  var logical;
                  var next;
                  var self = this;
                  function insideCondition() {
                      var cond = self.negatedCondition(needsParens) || self.parenthesisCondition(needsParens);
                      if (!cond && !needsParens) {
                          return self.atomicCondition(needsParens);
                      }
                      return cond;
                  }
                  function and() {
                      return parserInput.$str('and');
                  }
                  result = insideCondition();
                  if (!result) {
                      return;
                  }
                  logical = and();
                  if (logical) {
                      next = this.conditionAnd(needsParens);
                      if (next) {
                          result = new (tree.Condition)(logical, result, next);
                      }
                      else {
                          return;
                      }
                  }
                  return result;
              },
              negatedCondition: function (needsParens) {
                  if (parserInput.$str('not')) {
                      var result = this.parenthesisCondition(needsParens);
                      if (result) {
                          result.negate = !result.negate;
                      }
                      return result;
                  }
              },
              parenthesisCondition: function (needsParens) {
                  function tryConditionFollowedByParenthesis(me) {
                      var body;
                      parserInput.save();
                      body = me.condition(needsParens);
                      if (!body) {
                          parserInput.restore();
                          return;
                      }
                      if (!parserInput.$char(')')) {
                          parserInput.restore();
                          return;
                      }
                      parserInput.forget();
                      return body;
                  }
                  var body;
                  parserInput.save();
                  if (!parserInput.$str('(')) {
                      parserInput.restore();
                      return;
                  }
                  body = tryConditionFollowedByParenthesis(this);
                  if (body) {
                      parserInput.forget();
                      return body;
                  }
                  body = this.atomicCondition(needsParens);
                  if (!body) {
                      parserInput.restore();
                      return;
                  }
                  if (!parserInput.$char(')')) {
                      parserInput.restore("expected ')' got '" + parserInput.currentChar() + "'");
                      return;
                  }
                  parserInput.forget();
                  return body;
              },
              atomicCondition: function (needsParens) {
                  var entities = this.entities;
                  var index = parserInput.i;
                  var a;
                  var b;
                  var c;
                  var op;
                  function cond() {
                      return this.addition() || entities.keyword() || entities.quoted() || entities.mixinLookup();
                  }
                  cond = cond.bind(this);
                  a = cond();
                  if (a) {
                      if (parserInput.$char('>')) {
                          if (parserInput.$char('=')) {
                              op = '>=';
                          }
                          else {
                              op = '>';
                          }
                      }
                      else if (parserInput.$char('<')) {
                          if (parserInput.$char('=')) {
                              op = '<=';
                          }
                          else {
                              op = '<';
                          }
                      }
                      else if (parserInput.$char('=')) {
                          if (parserInput.$char('>')) {
                              op = '=>';
                          }
                          else if (parserInput.$char('<')) {
                              op = '=<';
                          }
                          else {
                              op = '=';
                          }
                      }
                      if (op) {
                          b = cond();
                          if (b) {
                              c = new (tree.Condition)(op, a, b, index, false);
                          }
                          else {
                              error('expected expression');
                          }
                      }
                      else {
                          c = new (tree.Condition)('=', a, new (tree.Keyword)('true'), index, false);
                      }
                      return c;
                  }
              },
              //
              // An operand is anything that can be part of an operation,
              // such as a Color, or a Variable
              //
              operand: function () {
                  var entities = this.entities;
                  var negate;
                  if (parserInput.peek(/^-[@\$\(]/)) {
                      negate = parserInput.$char('-');
                  }
                  var o = this.sub() || entities.dimension() ||
                      entities.color() || entities.variable() ||
                      entities.property() || entities.call() ||
                      entities.quoted(true) || entities.colorKeyword() ||
                      entities.mixinLookup();
                  if (negate) {
                      o.parensInOp = true;
                      o = new (tree.Negative)(o);
                  }
                  return o;
              },
              //
              // Expressions either represent mathematical operations,
              // or white-space delimited Entities.
              //
              //     1px solid black
              //     @var * 2
              //
              expression: function () {
                  var entities = [];
                  var e;
                  var delim;
                  var index = parserInput.i;
                  do {
                      e = this.comment();
                      if (e) {
                          entities.push(e);
                          continue;
                      }
                      e = this.addition() || this.entity();
                      if (e instanceof tree.Comment) {
                          e = null;
                      }
                      if (e) {
                          entities.push(e);
                          // operations do not allow keyword "/" dimension (e.g. small/20px) so we support that here
                          if (!parserInput.peek(/^\/[\/*]/)) {
                              delim = parserInput.$char('/');
                              if (delim) {
                                  entities.push(new (tree.Anonymous)(delim, index));
                              }
                          }
                      }
                  } while (e);
                  if (entities.length > 0) {
                      return new (tree.Expression)(entities);
                  }
              },
              property: function () {
                  var name = parserInput.$re(/^(\*?-?[_a-zA-Z0-9-]+)\s*:/);
                  if (name) {
                      return name[1];
                  }
              },
              ruleProperty: function () {
                  var name = [];
                  var index = [];
                  var s;
                  var k;
                  parserInput.save();
                  var simpleProperty = parserInput.$re(/^([_a-zA-Z0-9-]+)\s*:/);
                  if (simpleProperty) {
                      name = [new (tree.Keyword)(simpleProperty[1])];
                      parserInput.forget();
                      return name;
                  }
                  function match(re) {
                      var i = parserInput.i;
                      var chunk = parserInput.$re(re);
                      if (chunk) {
                          index.push(i);
                          return name.push(chunk[1]);
                      }
                  }
                  match(/^(\*?)/);
                  while (true) {
                      if (!match(/^((?:[\w-]+)|(?:[@\$]\{[\w-]+\}))/)) {
                          break;
                      }
                  }
                  if ((name.length > 1) && match(/^((?:\+_|\+)?)\s*:/)) {
                      parserInput.forget();
                      // at last, we have the complete match now. move forward,
                      // convert name particles to tree objects and return:
                      if (name[0] === '') {
                          name.shift();
                          index.shift();
                      }
                      for (k = 0; k < name.length; k++) {
                          s = name[k];
                          name[k] = (s.charAt(0) !== '@' && s.charAt(0) !== '$') ?
                              new (tree.Keyword)(s) :
                              (s.charAt(0) === '@' ?
                                  new (tree.Variable)("@" + s.slice(2, -1), index[k], fileInfo) :
                                  new (tree.Property)("$" + s.slice(2, -1), index[k], fileInfo));
                      }
                      return name;
                  }
                  parserInput.restore();
              }
          }
      };
  };
  Parser.serializeVars = function (vars) {
      var s = '';
      for (var name_1 in vars) {
          if (Object.hasOwnProperty.call(vars, name_1)) {
              var value = vars[name_1];
              s += ((name_1[0] === '@') ? '' : '@') + name_1 + ": " + value + ((String(value).slice(-1) === ';') ? '' : ';');
          }
      }
      return s;
  };

  function boolean(condition) {
      return condition ? Keyword.True : Keyword.False;
  }
  function If(condition, trueValue, falseValue) {
      return condition ? trueValue
          : (falseValue || new Anonymous);
  }
  var boolean$1 = { boolean: boolean, 'if': If };

  var colorFunctions;
  function clamp$1(val) {
      return Math.min(1, Math.max(0, val));
  }
  function hsla(origColor, hsl) {
      var color = colorFunctions.hsla(hsl.h, hsl.s, hsl.l, hsl.a);
      if (color) {
          if (origColor.value &&
              /^(rgb|hsl)/.test(origColor.value)) {
              color.value = origColor.value;
          }
          else {
              color.value = 'rgb';
          }
          return color;
      }
  }
  function toHSL(color) {
      if (color.toHSL) {
          return color.toHSL();
      }
      else {
          throw new Error('Argument cannot be evaluated to a color');
      }
  }
  function toHSV(color) {
      if (color.toHSV) {
          return color.toHSV();
      }
      else {
          throw new Error('Argument cannot be evaluated to a color');
      }
  }
  function number(n) {
      if (n instanceof Dimension) {
          return parseFloat(n.unit.is('%') ? n.value / 100 : n.value);
      }
      else if (typeof n === 'number') {
          return n;
      }
      else {
          throw {
              type: 'Argument',
              message: 'color functions take numbers as parameters'
          };
      }
  }
  function scaled(n, size) {
      if (n instanceof Dimension && n.unit.is('%')) {
          return parseFloat(n.value * size / 100);
      }
      else {
          return number(n);
      }
  }
  colorFunctions = {
      rgb: function (r, g, b) {
          var color = colorFunctions.rgba(r, g, b, 1.0);
          if (color) {
              color.value = 'rgb';
              return color;
          }
      },
      rgba: function (r, g, b, a) {
          try {
              if (r instanceof Color) {
                  if (g) {
                      a = number(g);
                  }
                  else {
                      a = r.alpha;
                  }
                  return new Color(r.rgb, a, 'rgba');
              }
              var rgb = [r, g, b].map(function (c) { return scaled(c, 255); });
              a = number(a);
              return new Color(rgb, a, 'rgba');
          }
          catch (e) { }
      },
      hsl: function (h, s, l) {
          var color = colorFunctions.hsla(h, s, l, 1.0);
          if (color) {
              color.value = 'hsl';
              return color;
          }
      },
      hsla: function (h, s, l, a) {
          try {
              if (h instanceof Color) {
                  if (s) {
                      a = number(s);
                  }
                  else {
                      a = h.alpha;
                  }
                  return new Color(h.rgb, a, 'hsla');
              }
              var m1_1;
              var m2_1;
              function hue(h) {
                  h = h < 0 ? h + 1 : (h > 1 ? h - 1 : h);
                  if (h * 6 < 1) {
                      return m1_1 + (m2_1 - m1_1) * h * 6;
                  }
                  else if (h * 2 < 1) {
                      return m2_1;
                  }
                  else if (h * 3 < 2) {
                      return m1_1 + (m2_1 - m1_1) * (2 / 3 - h) * 6;
                  }
                  else {
                      return m1_1;
                  }
              }
              h = (number(h) % 360) / 360;
              s = clamp$1(number(s));
              l = clamp$1(number(l));
              a = clamp$1(number(a));
              m2_1 = l <= 0.5 ? l * (s + 1) : l + s - l * s;
              m1_1 = l * 2 - m2_1;
              var rgb = [
                  hue(h + 1 / 3) * 255,
                  hue(h) * 255,
                  hue(h - 1 / 3) * 255
              ];
              a = number(a);
              return new Color(rgb, a, 'hsla');
          }
          catch (e) { }
      },
      hsv: function (h, s, v) {
          return colorFunctions.hsva(h, s, v, 1.0);
      },
      hsva: function (h, s, v, a) {
          h = ((number(h) % 360) / 360) * 360;
          s = number(s);
          v = number(v);
          a = number(a);
          var i;
          var f;
          i = Math.floor((h / 60) % 6);
          f = (h / 60) - i;
          var vs = [v,
              v * (1 - s),
              v * (1 - f * s),
              v * (1 - (1 - f) * s)];
          var perm = [[0, 3, 1],
              [2, 0, 1],
              [1, 0, 3],
              [1, 2, 0],
              [3, 1, 0],
              [0, 1, 2]];
          return colorFunctions.rgba(vs[perm[i][0]] * 255, vs[perm[i][1]] * 255, vs[perm[i][2]] * 255, a);
      },
      hue: function (color) {
          return new Dimension(toHSL(color).h);
      },
      saturation: function (color) {
          return new Dimension(toHSL(color).s * 100, '%');
      },
      lightness: function (color) {
          return new Dimension(toHSL(color).l * 100, '%');
      },
      hsvhue: function (color) {
          return new Dimension(toHSV(color).h);
      },
      hsvsaturation: function (color) {
          return new Dimension(toHSV(color).s * 100, '%');
      },
      hsvvalue: function (color) {
          return new Dimension(toHSV(color).v * 100, '%');
      },
      red: function (color) {
          return new Dimension(color.rgb[0]);
      },
      green: function (color) {
          return new Dimension(color.rgb[1]);
      },
      blue: function (color) {
          return new Dimension(color.rgb[2]);
      },
      alpha: function (color) {
          return new Dimension(toHSL(color).a);
      },
      luma: function (color) {
          return new Dimension(color.luma() * color.alpha * 100, '%');
      },
      luminance: function (color) {
          var luminance = (0.2126 * color.rgb[0] / 255) +
              (0.7152 * color.rgb[1] / 255) +
              (0.0722 * color.rgb[2] / 255);
          return new Dimension(luminance * color.alpha * 100, '%');
      },
      saturate: function (color, amount, method) {
          // filter: saturate(3.2);
          // should be kept as is, so check for color
          if (!color.rgb) {
              return null;
          }
          var hsl = toHSL(color);
          if (typeof method !== 'undefined' && method.value === 'relative') {
              hsl.s += hsl.s * amount.value / 100;
          }
          else {
              hsl.s += amount.value / 100;
          }
          hsl.s = clamp$1(hsl.s);
          return hsla(color, hsl);
      },
      desaturate: function (color, amount, method) {
          var hsl = toHSL(color);
          if (typeof method !== 'undefined' && method.value === 'relative') {
              hsl.s -= hsl.s * amount.value / 100;
          }
          else {
              hsl.s -= amount.value / 100;
          }
          hsl.s = clamp$1(hsl.s);
          return hsla(color, hsl);
      },
      lighten: function (color, amount, method) {
          var hsl = toHSL(color);
          if (typeof method !== 'undefined' && method.value === 'relative') {
              hsl.l += hsl.l * amount.value / 100;
          }
          else {
              hsl.l += amount.value / 100;
          }
          hsl.l = clamp$1(hsl.l);
          return hsla(color, hsl);
      },
      darken: function (color, amount, method) {
          var hsl = toHSL(color);
          if (typeof method !== 'undefined' && method.value === 'relative') {
              hsl.l -= hsl.l * amount.value / 100;
          }
          else {
              hsl.l -= amount.value / 100;
          }
          hsl.l = clamp$1(hsl.l);
          return hsla(color, hsl);
      },
      fadein: function (color, amount, method) {
          var hsl = toHSL(color);
          if (typeof method !== 'undefined' && method.value === 'relative') {
              hsl.a += hsl.a * amount.value / 100;
          }
          else {
              hsl.a += amount.value / 100;
          }
          hsl.a = clamp$1(hsl.a);
          return hsla(color, hsl);
      },
      fadeout: function (color, amount, method) {
          var hsl = toHSL(color);
          if (typeof method !== 'undefined' && method.value === 'relative') {
              hsl.a -= hsl.a * amount.value / 100;
          }
          else {
              hsl.a -= amount.value / 100;
          }
          hsl.a = clamp$1(hsl.a);
          return hsla(color, hsl);
      },
      fade: function (color, amount) {
          var hsl = toHSL(color);
          hsl.a = amount.value / 100;
          hsl.a = clamp$1(hsl.a);
          return hsla(color, hsl);
      },
      spin: function (color, amount) {
          var hsl = toHSL(color);
          var hue = (hsl.h + amount.value) % 360;
          hsl.h = hue < 0 ? 360 + hue : hue;
          return hsla(color, hsl);
      },
      //
      // Copyright (c) 2006-2009 Hampton Catlin, Natalie Weizenbaum, and Chris Eppstein
      // http://sass-lang.com
      //
      mix: function (color1, color2, weight) {
          if (!weight) {
              weight = new Dimension(50);
          }
          var p = weight.value / 100.0;
          var w = p * 2 - 1;
          var a = toHSL(color1).a - toHSL(color2).a;
          var w1 = (((w * a == -1) ? w : (w + a) / (1 + w * a)) + 1) / 2.0;
          var w2 = 1 - w1;
          var rgb = [color1.rgb[0] * w1 + color2.rgb[0] * w2,
              color1.rgb[1] * w1 + color2.rgb[1] * w2,
              color1.rgb[2] * w1 + color2.rgb[2] * w2];
          var alpha = color1.alpha * p + color2.alpha * (1 - p);
          return new Color(rgb, alpha);
      },
      greyscale: function (color) {
          return colorFunctions.desaturate(color, new Dimension(100));
      },
      contrast: function (color, dark, light, threshold) {
          // filter: contrast(3.2);
          // should be kept as is, so check for color
          if (!color.rgb) {
              return null;
          }
          if (typeof light === 'undefined') {
              light = colorFunctions.rgba(255, 255, 255, 1.0);
          }
          if (typeof dark === 'undefined') {
              dark = colorFunctions.rgba(0, 0, 0, 1.0);
          }
          // Figure out which is actually light and dark:
          if (dark.luma() > light.luma()) {
              var t = light;
              light = dark;
              dark = t;
          }
          if (typeof threshold === 'undefined') {
              threshold = 0.43;
          }
          else {
              threshold = number(threshold);
          }
          if (color.luma() < threshold) {
              return light;
          }
          else {
              return dark;
          }
      },
      // Changes made in 2.7.0 - Reverted in 3.0.0
      // contrast: function (color, color1, color2, threshold) {
      //     // Return which of `color1` and `color2` has the greatest contrast with `color`
      //     // according to the standard WCAG contrast ratio calculation.
      //     // http://www.w3.org/TR/WCAG20/#contrast-ratiodef
      //     // The threshold param is no longer used, in line with SASS.
      //     // filter: contrast(3.2);
      //     // should be kept as is, so check for color
      //     if (!color.rgb) {
      //         return null;
      //     }
      //     if (typeof color1 === 'undefined') {
      //         color1 = colorFunctions.rgba(0, 0, 0, 1.0);
      //     }
      //     if (typeof color2 === 'undefined') {
      //         color2 = colorFunctions.rgba(255, 255, 255, 1.0);
      //     }
      //     var contrast1, contrast2;
      //     var luma = color.luma();
      //     var luma1 = color1.luma();
      //     var luma2 = color2.luma();
      //     // Calculate contrast ratios for each color
      //     if (luma > luma1) {
      //         contrast1 = (luma + 0.05) / (luma1 + 0.05);
      //     } else {
      //         contrast1 = (luma1 + 0.05) / (luma + 0.05);
      //     }
      //     if (luma > luma2) {
      //         contrast2 = (luma + 0.05) / (luma2 + 0.05);
      //     } else {
      //         contrast2 = (luma2 + 0.05) / (luma + 0.05);
      //     }
      //     if (contrast1 > contrast2) {
      //         return color1;
      //     } else {
      //         return color2;
      //     }
      // },
      argb: function (color) {
          return new Anonymous(color.toARGB());
      },
      color: function (c) {
          if ((c instanceof Quoted) &&
              (/^#([A-Fa-f0-9]{8}|[A-Fa-f0-9]{6}|[A-Fa-f0-9]{3,4})$/i.test(c.value))) {
              var val = c.value.slice(1);
              return new Color(val, undefined, "#" + val);
          }
          if ((c instanceof Color) || (c = Color.fromKeyword(c.value))) {
              c.value = undefined;
              return c;
          }
          throw {
              type: 'Argument',
              message: 'argument must be a color keyword or 3|4|6|8 digit hex e.g. #FFF'
          };
      },
      tint: function (color, amount) {
          return colorFunctions.mix(colorFunctions.rgb(255, 255, 255), color, amount);
      },
      shade: function (color, amount) {
          return colorFunctions.mix(colorFunctions.rgb(0, 0, 0), color, amount);
      }
  };
  var color = colorFunctions;

  // Color Blending
  // ref: http://www.w3.org/TR/compositing-1
  function colorBlend(mode, color1, color2) {
      var ab = color1.alpha; // result
      var // backdrop
      cb;
      var as = color2.alpha;
      var // source
      cs;
      var ar;
      var cr;
      var r = [];
      ar = as + ab * (1 - as);
      for (var i_1 = 0; i_1 < 3; i_1++) {
          cb = color1.rgb[i_1] / 255;
          cs = color2.rgb[i_1] / 255;
          cr = mode(cb, cs);
          if (ar) {
              cr = (as * cs + ab * (cb -
                  as * (cb + cs - cr))) / ar;
          }
          r[i_1] = cr * 255;
      }
      return new Color(r, ar);
  }
  var colorBlendModeFunctions = {
      multiply: function (cb, cs) {
          return cb * cs;
      },
      screen: function (cb, cs) {
          return cb + cs - cb * cs;
      },
      overlay: function (cb, cs) {
          cb *= 2;
          return (cb <= 1) ?
              colorBlendModeFunctions.multiply(cb, cs) :
              colorBlendModeFunctions.screen(cb - 1, cs);
      },
      softlight: function (cb, cs) {
          var d = 1;
          var e = cb;
          if (cs > 0.5) {
              e = 1;
              d = (cb > 0.25) ? Math.sqrt(cb)
                  : ((16 * cb - 12) * cb + 4) * cb;
          }
          return cb - (1 - 2 * cs) * e * (d - cb);
      },
      hardlight: function (cb, cs) {
          return colorBlendModeFunctions.overlay(cs, cb);
      },
      difference: function (cb, cs) {
          return Math.abs(cb - cs);
      },
      exclusion: function (cb, cs) {
          return cb + cs - 2 * cb * cs;
      },
      // non-w3c functions:
      average: function (cb, cs) {
          return (cb + cs) / 2;
      },
      negation: function (cb, cs) {
          return 1 - Math.abs(cb + cs - 1);
      }
  };
  for (var f in colorBlendModeFunctions) {
      if (colorBlendModeFunctions.hasOwnProperty(f)) {
          colorBlend[f] = colorBlend.bind(null, colorBlendModeFunctions[f]);
      }
  }

  var dataUri = (function (environment) {
      var fallback = function (functionThis, node) { return new URL(node, functionThis.index, functionThis.currentFileInfo).eval(functionThis.context); };
      return { 'data-uri': function (mimetypeNode, filePathNode) {
              if (!filePathNode) {
                  filePathNode = mimetypeNode;
                  mimetypeNode = null;
              }
              var mimetype = mimetypeNode && mimetypeNode.value;
              var filePath = filePathNode.value;
              var currentFileInfo = this.currentFileInfo;
              var currentDirectory = currentFileInfo.rewriteUrls ?
                  currentFileInfo.currentDirectory : currentFileInfo.entryPath;
              var fragmentStart = filePath.indexOf('#');
              var fragment = '';
              if (fragmentStart !== -1) {
                  fragment = filePath.slice(fragmentStart);
                  filePath = filePath.slice(0, fragmentStart);
              }
              var context = clone(this.context);
              context.rawBuffer = true;
              var fileManager = environment.getFileManager(filePath, currentDirectory, context, environment, true);
              if (!fileManager) {
                  return fallback(this, filePathNode);
              }
              var useBase64 = false;
              // detect the mimetype if not given
              if (!mimetypeNode) {
                  mimetype = environment.mimeLookup(filePath);
                  if (mimetype === 'image/svg+xml') {
                      useBase64 = false;
                  }
                  else {
                      // use base 64 unless it's an ASCII or UTF-8 format
                      var charset = environment.charsetLookup(mimetype);
                      useBase64 = ['US-ASCII', 'UTF-8'].indexOf(charset) < 0;
                  }
                  if (useBase64) {
                      mimetype += ';base64';
                  }
              }
              else {
                  useBase64 = /;base64$/.test(mimetype);
              }
              var fileSync = fileManager.loadFileSync(filePath, currentDirectory, context, environment);
              if (!fileSync.contents) {
                  logger.warn("Skipped data-uri embedding of " + filePath + " because file not found");
                  return fallback(this, filePathNode || mimetypeNode);
              }
              var buf = fileSync.contents;
              if (useBase64 && !environment.encodeBase64) {
                  return fallback(this, filePathNode);
              }
              buf = useBase64 ? environment.encodeBase64(buf) : encodeURIComponent(buf);
              var uri = "data:" + mimetype + "," + buf + fragment;
              return new URL(new Quoted("\"" + uri + "\"", uri, false, this.index, this.currentFileInfo), this.index, this.currentFileInfo);
          } };
  });

  var getItemsFromNode = function (node) {
      // handle non-array values as an array of length 1
      // return 'undefined' if index is invalid
      var items = Array.isArray(node.value) ?
          node.value : Array(node);
      return items;
  };
  var list = {
      _SELF: function (n) {
          return n;
      },
      extract: function (values, index) {
          // (1-based index)
          index = index.value - 1;
          return getItemsFromNode(values)[index];
      },
      length: function (values) {
          return new Dimension(getItemsFromNode(values).length);
      },
      /**
       * Creates a Less list of incremental values.
       * Modeled after Lodash's range function, also exists natively in PHP
       *
       * @param {Dimension} [start=1]
       * @param {Dimension} end  - e.g. 10 or 10px - unit is added to output
       * @param {Dimension} [step=1]
       */
      range: function (start, end, step) {
          var from;
          var to;
          var stepValue = 1;
          var list = [];
          if (end) {
              to = end;
              from = start.value;
              if (step) {
                  stepValue = step.value;
              }
          }
          else {
              from = 1;
              to = start;
          }
          for (var i_1 = from; i_1 <= to.value; i_1 += stepValue) {
              list.push(new Dimension(i_1, to.unit));
          }
          return new Expression(list);
      },
      each: function (list, rs) {
          var rules = [];
          var newRules;
          var iterator;
          if (list.value && !(list instanceof Quoted)) {
              if (Array.isArray(list.value)) {
                  iterator = list.value;
              }
              else {
                  iterator = [list.value];
              }
          }
          else if (list.ruleset) {
              iterator = list.ruleset.rules;
          }
          else if (list.rules) {
              iterator = list.rules;
          }
          else if (Array.isArray(list)) {
              iterator = list;
          }
          else {
              iterator = [list];
          }
          var valueName = '@value';
          var keyName = '@key';
          var indexName = '@index';
          if (rs.params) {
              valueName = rs.params[0] && rs.params[0].name;
              keyName = rs.params[1] && rs.params[1].name;
              indexName = rs.params[2] && rs.params[2].name;
              rs = rs.rules;
          }
          else {
              rs = rs.ruleset;
          }
          for (var i_2 = 0; i_2 < iterator.length; i_2++) {
              var key = void 0;
              var value = void 0;
              var item = iterator[i_2];
              if (item instanceof Declaration) {
                  key = typeof item.name === 'string' ? item.name : item.name[0].value;
                  value = item.value;
              }
              else {
                  key = new Dimension(i_2 + 1);
                  value = item;
              }
              if (item instanceof Comment) {
                  continue;
              }
              newRules = rs.rules.slice(0);
              if (valueName) {
                  newRules.push(new Declaration(valueName, value, false, false, this.index, this.currentFileInfo));
              }
              if (indexName) {
                  newRules.push(new Declaration(indexName, new Dimension(i_2 + 1), false, false, this.index, this.currentFileInfo));
              }
              if (keyName) {
                  newRules.push(new Declaration(keyName, key, false, false, this.index, this.currentFileInfo));
              }
              rules.push(new Ruleset([new (Selector)([new Element("", '&')])], newRules, rs.strictImports, rs.visibilityInfo()));
          }
          return new Ruleset([new (Selector)([new Element("", '&')])], rules, rs.strictImports, rs.visibilityInfo()).eval(this.context);
      }
  };

  var MathHelper = function (fn, unit, n) {
      if (!(n instanceof Dimension)) {
          throw { type: 'Argument', message: 'argument must be a number' };
      }
      if (unit == null) {
          unit = n.unit;
      }
      else {
          n = n.unify();
      }
      return new Dimension(fn(parseFloat(n.value)), unit);
  };

  var mathFunctions = {
      // name,  unit
      ceil: null,
      floor: null,
      sqrt: null,
      abs: null,
      tan: '',
      sin: '',
      cos: '',
      atan: 'rad',
      asin: 'rad',
      acos: 'rad'
  };
  for (var f$1 in mathFunctions) {
      if (mathFunctions.hasOwnProperty(f$1)) {
          mathFunctions[f$1] = MathHelper.bind(null, Math[f$1], mathFunctions[f$1]);
      }
  }
  mathFunctions.round = function (n, f) {
      var fraction = typeof f === 'undefined' ? 0 : f.value;
      return MathHelper(function (num) { return num.toFixed(fraction); }, null, n);
  };

  var minMax = function (isMin, args) {
      args = Array.prototype.slice.call(args);
      switch (args.length) {
          case 0: throw { type: 'Argument', message: 'one or more arguments required' };
      }
      var i; // key is the unit.toString() for unified Dimension values,
      var j;
      var current;
      var currentUnified;
      var referenceUnified;
      var unit;
      var unitStatic;
      var unitClone;
      var // elems only contains original argument values.
      order = [];
      var values = {};
      // value is the index into the order array.
      for (i = 0; i < args.length; i++) {
          current = args[i];
          if (!(current instanceof Dimension)) {
              if (Array.isArray(args[i].value)) {
                  Array.prototype.push.apply(args, Array.prototype.slice.call(args[i].value));
              }
              continue;
          }
          currentUnified = current.unit.toString() === '' && unitClone !== undefined ? new Dimension(current.value, unitClone).unify() : current.unify();
          unit = currentUnified.unit.toString() === '' && unitStatic !== undefined ? unitStatic : currentUnified.unit.toString();
          unitStatic = unit !== '' && unitStatic === undefined || unit !== '' && order[0].unify().unit.toString() === '' ? unit : unitStatic;
          unitClone = unit !== '' && unitClone === undefined ? current.unit.toString() : unitClone;
          j = values[''] !== undefined && unit !== '' && unit === unitStatic ? values[''] : values[unit];
          if (j === undefined) {
              if (unitStatic !== undefined && unit !== unitStatic) {
                  throw { type: 'Argument', message: 'incompatible types' };
              }
              values[unit] = order.length;
              order.push(current);
              continue;
          }
          referenceUnified = order[j].unit.toString() === '' && unitClone !== undefined ? new Dimension(order[j].value, unitClone).unify() : order[j].unify();
          if (isMin && currentUnified.value < referenceUnified.value ||
              !isMin && currentUnified.value > referenceUnified.value) {
              order[j] = current;
          }
      }
      if (order.length == 1) {
          return order[0];
      }
      args = order.map(function (a) { return a.toCSS(this.context); }).join(this.context.compress ? ',' : ', ');
      return new Anonymous((isMin ? 'min' : 'max') + "(" + args + ")");
  };
  var number$1 = {
      min: function () {
          var args = [];
          for (var _i = 0; _i < arguments.length; _i++) {
              args[_i] = arguments[_i];
          }
          return minMax(true, args);
      },
      max: function () {
          var args = [];
          for (var _i = 0; _i < arguments.length; _i++) {
              args[_i] = arguments[_i];
          }
          return minMax(false, args);
      },
      convert: function (val, unit) {
          return val.convertTo(unit.value);
      },
      pi: function () {
          return new Dimension(Math.PI);
      },
      mod: function (a, b) {
          return new Dimension(a.value % b.value, a.unit);
      },
      pow: function (x, y) {
          if (typeof x === 'number' && typeof y === 'number') {
              x = new Dimension(x);
              y = new Dimension(y);
          }
          else if (!(x instanceof Dimension) || !(y instanceof Dimension)) {
              throw { type: 'Argument', message: 'arguments must be numbers' };
          }
          return new Dimension(Math.pow(x.value, y.value), x.unit);
      },
      percentage: function (n) {
          var result = MathHelper(function (num) { return num * 100; }, '%', n);
          return result;
      }
  };

  var string = {
      e: function (str) {
          return new Quoted('"', str instanceof JavaScript ? str.evaluated : str.value, true);
      },
      escape: function (str) {
          return new Anonymous(encodeURI(str.value).replace(/=/g, '%3D').replace(/:/g, '%3A').replace(/#/g, '%23').replace(/;/g, '%3B')
              .replace(/\(/g, '%28').replace(/\)/g, '%29'));
      },
      replace: function (string, pattern, replacement, flags) {
          var result = string.value;
          replacement = (replacement.type === 'Quoted') ?
              replacement.value : replacement.toCSS();
          result = result.replace(new RegExp(pattern.value, flags ? flags.value : ''), replacement);
          return new Quoted(string.quote || '', result, string.escaped);
      },
      '%': function (string /* arg, arg, ... */) {
          var args = Array.prototype.slice.call(arguments, 1);
          var result = string.value;
          var _loop_1 = function (i_1) {
              /* jshint loopfunc:true */
              result = result.replace(/%[sda]/i, function (token) {
                  var value = ((args[i_1].type === 'Quoted') &&
                      token.match(/s/i)) ? args[i_1].value : args[i_1].toCSS();
                  return token.match(/[A-Z]$/) ? encodeURIComponent(value) : value;
              });
          };
          for (var i_1 = 0; i_1 < args.length; i_1++) {
              _loop_1(i_1);
          }
          result = result.replace(/%%/g, '%');
          return new Quoted(string.quote || '', result, string.escaped);
      }
  };

  var svg = (function (environment) {
      return { 'svg-gradient': function (direction) {
              var stops;
              var gradientDirectionSvg;
              var gradientType = 'linear';
              var rectangleDimension = 'x="0" y="0" width="1" height="1"';
              var renderEnv = { compress: false };
              var returner;
              var directionValue = direction.toCSS(renderEnv);
              var i;
              var color;
              var position;
              var positionValue;
              var alpha;
              function throwArgumentDescriptor() {
                  throw { type: 'Argument',
                      message: 'svg-gradient expects direction, start_color [start_position], [color position,]...,' +
                          ' end_color [end_position] or direction, color list' };
              }
              if (arguments.length == 2) {
                  if (arguments[1].value.length < 2) {
                      throwArgumentDescriptor();
                  }
                  stops = arguments[1].value;
              }
              else if (arguments.length < 3) {
                  throwArgumentDescriptor();
              }
              else {
                  stops = Array.prototype.slice.call(arguments, 1);
              }
              switch (directionValue) {
                  case 'to bottom':
                      gradientDirectionSvg = 'x1="0%" y1="0%" x2="0%" y2="100%"';
                      break;
                  case 'to right':
                      gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="0%"';
                      break;
                  case 'to bottom right':
                      gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="100%"';
                      break;
                  case 'to top right':
                      gradientDirectionSvg = 'x1="0%" y1="100%" x2="100%" y2="0%"';
                      break;
                  case 'ellipse':
                  case 'ellipse at center':
                      gradientType = 'radial';
                      gradientDirectionSvg = 'cx="50%" cy="50%" r="75%"';
                      rectangleDimension = 'x="-50" y="-50" width="101" height="101"';
                      break;
                  default:
                      throw { type: 'Argument', message: 'svg-gradient direction must be \'to bottom\', \'to right\',' +
                              ' \'to bottom right\', \'to top right\' or \'ellipse at center\'' };
              }
              returner = "<svg xmlns=\"http://www.w3.org/2000/svg\" viewBox=\"0 0 1 1\"><" + gradientType + "Gradient id=\"g\" " + gradientDirectionSvg + ">";
              for (i = 0; i < stops.length; i += 1) {
                  if (stops[i] instanceof Expression) {
                      color = stops[i].value[0];
                      position = stops[i].value[1];
                  }
                  else {
                      color = stops[i];
                      position = undefined;
                  }
                  if (!(color instanceof Color) || (!((i === 0 || i + 1 === stops.length) && position === undefined) && !(position instanceof Dimension))) {
                      throwArgumentDescriptor();
                  }
                  positionValue = position ? position.toCSS(renderEnv) : i === 0 ? '0%' : '100%';
                  alpha = color.alpha;
                  returner += "<stop offset=\"" + positionValue + "\" stop-color=\"" + color.toRGB() + "\"" + (alpha < 1 ? " stop-opacity=\"" + alpha + "\"" : '') + "/>";
              }
              returner += "</" + gradientType + "Gradient><rect " + rectangleDimension + " fill=\"url(#g)\" /></svg>";
              returner = encodeURIComponent(returner);
              returner = "data:image/svg+xml," + returner;
              return new URL(new Quoted("'" + returner + "'", returner, false, this.index, this.currentFileInfo), this.index, this.currentFileInfo);
          } };
  });

  var isa = function (n, Type) { return (n instanceof Type) ? Keyword.True : Keyword.False; };
  var isunit = function (n, unit) {
      if (unit === undefined) {
          throw { type: 'Argument', message: 'missing the required second argument to isunit.' };
      }
      unit = typeof unit.value === 'string' ? unit.value : unit;
      if (typeof unit !== 'string') {
          throw { type: 'Argument', message: 'Second argument to isunit should be a unit or a string.' };
      }
      return (n instanceof Dimension) && n.unit.is(unit) ? Keyword.True : Keyword.False;
  };
  var types = {
      isruleset: function (n) {
          return isa(n, DetachedRuleset);
      },
      iscolor: function (n) {
          return isa(n, Color);
      },
      isnumber: function (n) {
          return isa(n, Dimension);
      },
      isstring: function (n) {
          return isa(n, Quoted);
      },
      iskeyword: function (n) {
          return isa(n, Keyword);
      },
      isurl: function (n) {
          return isa(n, URL);
      },
      ispixel: function (n) {
          return isunit(n, 'px');
      },
      ispercentage: function (n) {
          return isunit(n, '%');
      },
      isem: function (n) {
          return isunit(n, 'em');
      },
      isunit: isunit,
      unit: function (val, unit) {
          if (!(val instanceof Dimension)) {
              throw { type: 'Argument',
                  message: "the first argument to unit must be a number" + (val instanceof Operation ? '. Have you forgotten parenthesis?' : '') };
          }
          if (unit) {
              if (unit instanceof Keyword) {
                  unit = unit.value;
              }
              else {
                  unit = unit.toCSS();
              }
          }
          else {
              unit = '';
          }
          return new Dimension(val.value, unit);
      },
      'get-unit': function (n) {
          return new Anonymous(n.unit);
      }
  };

  var Functions = (function (environment) {
      var functions = { functionRegistry: functionRegistry, functionCaller: functionCaller };
      // register functions
      functionRegistry.addMultiple(boolean$1);
      functionRegistry.add('default', defaultFunc.eval.bind(defaultFunc));
      functionRegistry.addMultiple(color);
      functionRegistry.addMultiple(colorBlend);
      functionRegistry.addMultiple(dataUri(environment));
      functionRegistry.addMultiple(list);
      functionRegistry.addMultiple(mathFunctions);
      functionRegistry.addMultiple(number$1);
      functionRegistry.addMultiple(string);
      functionRegistry.addMultiple(svg());
      functionRegistry.addMultiple(types);
      return functions;
  });

  var sourceMapOutput = (function (environment) {
      var SourceMapOutput = /** @class */ (function () {
          function SourceMapOutput(options) {
              this._css = [];
              this._rootNode = options.rootNode;
              this._contentsMap = options.contentsMap;
              this._contentsIgnoredCharsMap = options.contentsIgnoredCharsMap;
              if (options.sourceMapFilename) {
                  this._sourceMapFilename = options.sourceMapFilename.replace(/\\/g, '/');
              }
              this._outputFilename = options.outputFilename;
              this.sourceMapURL = options.sourceMapURL;
              if (options.sourceMapBasepath) {
                  this._sourceMapBasepath = options.sourceMapBasepath.replace(/\\/g, '/');
              }
              if (options.sourceMapRootpath) {
                  this._sourceMapRootpath = options.sourceMapRootpath.replace(/\\/g, '/');
                  if (this._sourceMapRootpath.charAt(this._sourceMapRootpath.length - 1) !== '/') {
                      this._sourceMapRootpath += '/';
                  }
              }
              else {
                  this._sourceMapRootpath = '';
              }
              this._outputSourceFiles = options.outputSourceFiles;
              this._sourceMapGeneratorConstructor = environment.getSourceMapGenerator();
              this._lineNumber = 0;
              this._column = 0;
          }
          SourceMapOutput.prototype.removeBasepath = function (path) {
              if (this._sourceMapBasepath && path.indexOf(this._sourceMapBasepath) === 0) {
                  path = path.substring(this._sourceMapBasepath.length);
                  if (path.charAt(0) === '\\' || path.charAt(0) === '/') {
                      path = path.substring(1);
                  }
              }
              return path;
          };
          SourceMapOutput.prototype.normalizeFilename = function (filename) {
              filename = filename.replace(/\\/g, '/');
              filename = this.removeBasepath(filename);
              return (this._sourceMapRootpath || '') + filename;
          };
          SourceMapOutput.prototype.add = function (chunk, fileInfo, index, mapLines) {
              // ignore adding empty strings
              if (!chunk) {
                  return;
              }
              var lines;
              var sourceLines;
              var columns;
              var sourceColumns;
              var i;
              if (fileInfo && fileInfo.filename) {
                  var inputSource = this._contentsMap[fileInfo.filename];
                  // remove vars/banner added to the top of the file
                  if (this._contentsIgnoredCharsMap[fileInfo.filename]) {
                      // adjust the index
                      index -= this._contentsIgnoredCharsMap[fileInfo.filename];
                      if (index < 0) {
                          index = 0;
                      }
                      // adjust the source
                      inputSource = inputSource.slice(this._contentsIgnoredCharsMap[fileInfo.filename]);
                  }
                  // ignore empty content
                  if (inputSource === undefined) {
                      return;
                  }
                  inputSource = inputSource.substring(0, index);
                  sourceLines = inputSource.split('\n');
                  sourceColumns = sourceLines[sourceLines.length - 1];
              }
              lines = chunk.split('\n');
              columns = lines[lines.length - 1];
              if (fileInfo && fileInfo.filename) {
                  if (!mapLines) {
                      this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + 1, column: this._column },
                          original: { line: sourceLines.length, column: sourceColumns.length },
                          source: this.normalizeFilename(fileInfo.filename) });
                  }
                  else {
                      for (i = 0; i < lines.length; i++) {
                          this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + i + 1, column: i === 0 ? this._column : 0 },
                              original: { line: sourceLines.length + i, column: i === 0 ? sourceColumns.length : 0 },
                              source: this.normalizeFilename(fileInfo.filename) });
                      }
                  }
              }
              if (lines.length === 1) {
                  this._column += columns.length;
              }
              else {
                  this._lineNumber += lines.length - 1;
                  this._column = columns.length;
              }
              this._css.push(chunk);
          };
          SourceMapOutput.prototype.isEmpty = function () {
              return this._css.length === 0;
          };
          SourceMapOutput.prototype.toCSS = function (context) {
              this._sourceMapGenerator = new this._sourceMapGeneratorConstructor({ file: this._outputFilename, sourceRoot: null });
              if (this._outputSourceFiles) {
                  for (var filename in this._contentsMap) {
                      if (this._contentsMap.hasOwnProperty(filename)) {
                          var source = this._contentsMap[filename];
                          if (this._contentsIgnoredCharsMap[filename]) {
                              source = source.slice(this._contentsIgnoredCharsMap[filename]);
                          }
                          this._sourceMapGenerator.setSourceContent(this.normalizeFilename(filename), source);
                      }
                  }
              }
              this._rootNode.genCSS(context, this);
              if (this._css.length > 0) {
                  var sourceMapURL = void 0;
                  var sourceMapContent = JSON.stringify(this._sourceMapGenerator.toJSON());
                  if (this.sourceMapURL) {
                      sourceMapURL = this.sourceMapURL;
                  }
                  else if (this._sourceMapFilename) {
                      sourceMapURL = this._sourceMapFilename;
                  }
                  this.sourceMapURL = sourceMapURL;
                  this.sourceMap = sourceMapContent;
              }
              return this._css.join('');
          };
          return SourceMapOutput;
      }());
      return SourceMapOutput;
  });

  var sourceMapBuilder = (function (SourceMapOutput, environment) {
      var SourceMapBuilder = /** @class */ (function () {
          function SourceMapBuilder(options) {
              this.options = options;
          }
          SourceMapBuilder.prototype.toCSS = function (rootNode, options, imports) {
              var sourceMapOutput = new SourceMapOutput({
                  contentsIgnoredCharsMap: imports.contentsIgnoredChars,
                  rootNode: rootNode,
                  contentsMap: imports.contents,
                  sourceMapFilename: this.options.sourceMapFilename,
                  sourceMapURL: this.options.sourceMapURL,
                  outputFilename: this.options.sourceMapOutputFilename,
                  sourceMapBasepath: this.options.sourceMapBasepath,
                  sourceMapRootpath: this.options.sourceMapRootpath,
                  outputSourceFiles: this.options.outputSourceFiles,
                  sourceMapGenerator: this.options.sourceMapGenerator,
                  sourceMapFileInline: this.options.sourceMapFileInline
              });
              var css = sourceMapOutput.toCSS(options);
              this.sourceMap = sourceMapOutput.sourceMap;
              this.sourceMapURL = sourceMapOutput.sourceMapURL;
              if (this.options.sourceMapInputFilename) {
                  this.sourceMapInputFilename = sourceMapOutput.normalizeFilename(this.options.sourceMapInputFilename);
              }
              if (this.options.sourceMapBasepath !== undefined && this.sourceMapURL !== undefined) {
                  this.sourceMapURL = sourceMapOutput.removeBasepath(this.sourceMapURL);
              }
              return css + this.getCSSAppendage();
          };
          SourceMapBuilder.prototype.getCSSAppendage = function () {
              var sourceMapURL = this.sourceMapURL;
              if (this.options.sourceMapFileInline) {
                  if (this.sourceMap === undefined) {
                      return '';
                  }
                  sourceMapURL = "data:application/json;base64," + environment.encodeBase64(this.sourceMap);
              }
              if (sourceMapURL) {
                  return "/*# sourceMappingURL=" + sourceMapURL + " */";
              }
              return '';
          };
          SourceMapBuilder.prototype.getExternalSourceMap = function () {
              return this.sourceMap;
          };
          SourceMapBuilder.prototype.setExternalSourceMap = function (sourceMap) {
              this.sourceMap = sourceMap;
          };
          SourceMapBuilder.prototype.isInline = function () {
              return this.options.sourceMapFileInline;
          };
          SourceMapBuilder.prototype.getSourceMapURL = function () {
              return this.sourceMapURL;
          };
          SourceMapBuilder.prototype.getOutputFilename = function () {
              return this.options.sourceMapOutputFilename;
          };
          SourceMapBuilder.prototype.getInputFilename = function () {
              return this.sourceMapInputFilename;
          };
          return SourceMapBuilder;
      }());
      return SourceMapBuilder;
  });

  var transformTree = (function (root, options) {
      if (options === void 0) { options = {}; }
      var evaldRoot;
      var variables = options.variables;
      var evalEnv = new contexts.Eval(options);
      //
      // Allows setting variables with a hash, so:
      //
      //   `{ color: new tree.Color('#f01') }` will become:
      //
      //   new tree.Declaration('@color',
      //     new tree.Value([
      //       new tree.Expression([
      //         new tree.Color('#f01')
      //       ])
      //     ])
      //   )
      //
      if (typeof variables === 'object' && !Array.isArray(variables)) {
          variables = Object.keys(variables).map(function (k) {
              var value = variables[k];
              if (!(value instanceof tree.Value)) {
                  if (!(value instanceof tree.Expression)) {
                      value = new tree.Expression([value]);
                  }
                  value = new tree.Value([value]);
              }
              return new tree.Declaration("@" + k, value, false, null, 0);
          });
          evalEnv.frames = [new tree.Ruleset(null, variables)];
      }
      var visitors$1 = [
          new visitors.JoinSelectorVisitor(),
          new visitors.MarkVisibleSelectorsVisitor(true),
          new visitors.ExtendVisitor(),
          new visitors.ToCSSVisitor({ compress: Boolean(options.compress) })
      ];
      var preEvalVisitors = [];
      var v;
      var visitorIterator;
      /**
       * first() / get() allows visitors to be added while visiting
       *
       * @todo Add scoping for visitors just like functions for @plugin; right now they're global
       */
      if (options.pluginManager) {
          visitorIterator = options.pluginManager.visitor();
          for (var i = 0; i < 2; i++) {
              visitorIterator.first();
              while ((v = visitorIterator.get())) {
                  if (v.isPreEvalVisitor) {
                      if (i === 0 || preEvalVisitors.indexOf(v) === -1) {
                          preEvalVisitors.push(v);
                          v.run(root);
                      }
                  }
                  else {
                      if (i === 0 || visitors$1.indexOf(v) === -1) {
                          if (v.isPreVisitor) {
                              visitors$1.unshift(v);
                          }
                          else {
                              visitors$1.push(v);
                          }
                      }
                  }
              }
          }
      }
      evaldRoot = root.eval(evalEnv);
      for (var i = 0; i < visitors$1.length; i++) {
          visitors$1[i].run(evaldRoot);
      }
      // Run any remaining visitors added after eval pass
      if (options.pluginManager) {
          visitorIterator.first();
          while ((v = visitorIterator.get())) {
              if (visitors$1.indexOf(v) === -1 && preEvalVisitors.indexOf(v) === -1) {
                  v.run(evaldRoot);
              }
          }
      }
      return evaldRoot;
  });

  var parseTree = (function (SourceMapBuilder) {
      var ParseTree = /** @class */ (function () {
          function ParseTree(root, imports) {
              this.root = root;
              this.imports = imports;
          }
          ParseTree.prototype.toCSS = function (options) {
              var evaldRoot;
              var result = {};
              var sourceMapBuilder;
              try {
                  evaldRoot = transformTree(this.root, options);
              }
              catch (e) {
                  throw new LessError(e, this.imports);
              }
              try {
                  var compress = Boolean(options.compress);
                  if (compress) {
                      logger.warn('The compress option has been deprecated. ' +
                          'We recommend you use a dedicated css minifier, for instance see less-plugin-clean-css.');
                  }
                  var toCSSOptions = {
                      compress: compress,
                      dumpLineNumbers: options.dumpLineNumbers,
                      strictUnits: Boolean(options.strictUnits),
                      numPrecision: 8
                  };
                  if (options.sourceMap) {
                      sourceMapBuilder = new SourceMapBuilder(options.sourceMap);
                      result.css = sourceMapBuilder.toCSS(evaldRoot, toCSSOptions, this.imports);
                  }
                  else {
                      result.css = evaldRoot.toCSS(toCSSOptions);
                  }
              }
              catch (e) {
                  throw new LessError(e, this.imports);
              }
              if (options.pluginManager) {
                  var postProcessors = options.pluginManager.getPostProcessors();
                  for (var i_1 = 0; i_1 < postProcessors.length; i_1++) {
                      result.css = postProcessors[i_1].process(result.css, { sourceMap: sourceMapBuilder, options: options, imports: this.imports });
                  }
              }
              if (options.sourceMap) {
                  result.map = sourceMapBuilder.getExternalSourceMap();
              }
              result.imports = [];
              for (var file_1 in this.imports.files) {
                  if (this.imports.files.hasOwnProperty(file_1) && file_1 !== this.imports.rootFilename) {
                      result.imports.push(file_1);
                  }
              }
              return result;
          };
          return ParseTree;
      }());
      return ParseTree;
  });

  var importManager = (function (environment) {
      // FileInfo = {
      //  'rewriteUrls' - option - whether to adjust URL's to be relative
      //  'filename' - full resolved filename of current file
      //  'rootpath' - path to append to normal URLs for this node
      //  'currentDirectory' - path to the current file, absolute
      //  'rootFilename' - filename of the base file
      //  'entryPath' - absolute path to the entry file
      //  'reference' - whether the file should not be output and only output parts that are referenced
      var ImportManager = /** @class */ (function () {
          function ImportManager(less, context, rootFileInfo) {
              this.less = less;
              this.rootFilename = rootFileInfo.filename;
              this.paths = context.paths || []; // Search paths, when importing
              this.contents = {}; // map - filename to contents of all the files
              this.contentsIgnoredChars = {}; // map - filename to lines at the beginning of each file to ignore
              this.mime = context.mime;
              this.error = null;
              this.context = context;
              // Deprecated? Unused outside of here, could be useful.
              this.queue = []; // Files which haven't been imported yet
          }
          /**
           * Add an import to be imported
           * @param path - the raw path
           * @param tryAppendExtension - whether to try appending a file extension (.less or .js if the path has no extension)
           * @param currentFileInfo - the current file info (used for instance to work out relative paths)
           * @param importOptions - import options
           * @param callback - callback for when it is imported
           */
          ImportManager.prototype.push = function (path, tryAppendExtension, currentFileInfo, importOptions, callback) {
              var importManager = this;
              var pluginLoader = this.context.pluginManager.Loader;
              this.queue.push(path);
              var fileParsedFunc = function (e, root, fullPath) {
                  importManager.queue.splice(importManager.queue.indexOf(path), 1); // Remove the path from the queue
                  var importedEqualsRoot = fullPath === importManager.rootFilename;
                  if (importOptions.optional && e) {
                      callback(null, { rules: [] }, false, null);
                      logger.info("The file " + fullPath + " was skipped because it was not found and the import was marked optional.");
                  }
                  else {
                      if (e && !importManager.error) {
                          importManager.error = e;
                      }
                      callback(e, root, importedEqualsRoot, fullPath);
                  }
              };
              var newFileInfo = {
                  rewriteUrls: this.context.rewriteUrls,
                  entryPath: currentFileInfo.entryPath,
                  rootpath: currentFileInfo.rootpath,
                  rootFilename: currentFileInfo.rootFilename
              };
              var fileManager = environment.getFileManager(path, currentFileInfo.currentDirectory, this.context, environment);
              if (!fileManager) {
                  fileParsedFunc({ message: "Could not find a file-manager for " + path });
                  return;
              }
              var loadFileCallback = function (loadedFile) {
                  var plugin;
                  var resolvedFilename = loadedFile.filename;
                  var contents = loadedFile.contents.replace(/^\uFEFF/, '');
                  // Pass on an updated rootpath if path of imported file is relative and file
                  // is in a (sub|sup) directory
                  //
                  // Examples:
                  // - If path of imported file is 'module/nav/nav.less' and rootpath is 'less/',
                  //   then rootpath should become 'less/module/nav/'
                  // - If path of imported file is '../mixins.less' and rootpath is 'less/',
                  //   then rootpath should become 'less/../'
                  newFileInfo.currentDirectory = fileManager.getPath(resolvedFilename);
                  if (newFileInfo.rewriteUrls) {
                      newFileInfo.rootpath = fileManager.join((importManager.context.rootpath || ''), fileManager.pathDiff(newFileInfo.currentDirectory, newFileInfo.entryPath));
                      if (!fileManager.isPathAbsolute(newFileInfo.rootpath) && fileManager.alwaysMakePathsAbsolute()) {
                          newFileInfo.rootpath = fileManager.join(newFileInfo.entryPath, newFileInfo.rootpath);
                      }
                  }
                  newFileInfo.filename = resolvedFilename;
                  var newEnv = new contexts.Parse(importManager.context);
                  newEnv.processImports = false;
                  importManager.contents[resolvedFilename] = contents;
                  if (currentFileInfo.reference || importOptions.reference) {
                      newFileInfo.reference = true;
                  }
                  if (importOptions.isPlugin) {
                      plugin = pluginLoader.evalPlugin(contents, newEnv, importManager, importOptions.pluginArgs, newFileInfo);
                      if (plugin instanceof LessError) {
                          fileParsedFunc(plugin, null, resolvedFilename);
                      }
                      else {
                          fileParsedFunc(null, plugin, resolvedFilename);
                      }
                  }
                  else if (importOptions.inline) {
                      fileParsedFunc(null, contents, resolvedFilename);
                  }
                  else {
                      new Parser(newEnv, importManager, newFileInfo).parse(contents, function (e, root) {
                          fileParsedFunc(e, root, resolvedFilename);
                      });
                  }
              };
              var promise;
              var context = clone(this.context);
              if (tryAppendExtension) {
                  context.ext = importOptions.isPlugin ? '.js' : '.less';
              }
              if (importOptions.isPlugin) {
                  context.mime = 'application/javascript';
                  promise = pluginLoader.loadPlugin(path, currentFileInfo.currentDirectory, context, environment, fileManager);
              }
              else {
                  promise = fileManager.loadFile(path, currentFileInfo.currentDirectory, context, environment, function (err, loadedFile) {
                      if (err) {
                          fileParsedFunc(err);
                      }
                      else {
                          loadFileCallback(loadedFile);
                      }
                  });
              }
              if (promise) {
                  promise.then(loadFileCallback, fileParsedFunc);
              }
          };
          return ImportManager;
      }());
      return ImportManager;
  });

  var Render = (function (environment, ParseTree, ImportManager) {
      var render = function (input, options, callback) {
          if (typeof options === 'function') {
              callback = options;
              options = copyOptions(this.options, {});
          }
          else {
              options = copyOptions(this.options, options || {});
          }
          if (!callback) {
              var self_1 = this;
              return new Promise(function (resolve, reject) {
                  render.call(self_1, input, options, function (err, output) {
                      if (err) {
                          reject(err);
                      }
                      else {
                          resolve(output);
                      }
                  });
              });
          }
          else {
              this.parse(input, options, function (err, root, imports, options) {
                  if (err) {
                      return callback(err);
                  }
                  var result;
                  try {
                      var parseTree = new ParseTree(root, imports);
                      result = parseTree.toCSS(options);
                  }
                  catch (err) {
                      return callback(err);
                  }
                  callback(null, result);
              });
          }
      };
      return render;
  });

  /**
   * Plugin Manager
   */
  var PluginManager = /** @class */ (function () {
      function PluginManager(less) {
          this.less = less;
          this.visitors = [];
          this.preProcessors = [];
          this.postProcessors = [];
          this.installedPlugins = [];
          this.fileManagers = [];
          this.iterator = -1;
          this.pluginCache = {};
          this.Loader = new less.PluginLoader(less);
      }
      /**
       * Adds all the plugins in the array
       * @param {Array} plugins
       */
      PluginManager.prototype.addPlugins = function (plugins) {
          if (plugins) {
              for (var i_1 = 0; i_1 < plugins.length; i_1++) {
                  this.addPlugin(plugins[i_1]);
              }
          }
      };
      /**
       *
       * @param plugin
       * @param {String} filename
       */
      PluginManager.prototype.addPlugin = function (plugin, filename, functionRegistry) {
          this.installedPlugins.push(plugin);
          if (filename) {
              this.pluginCache[filename] = plugin;
          }
          if (plugin.install) {
              plugin.install(this.less, this, functionRegistry || this.less.functions.functionRegistry);
          }
      };
      /**
       *
       * @param filename
       */
      PluginManager.prototype.get = function (filename) {
          return this.pluginCache[filename];
      };
      /**
       * Adds a visitor. The visitor object has options on itself to determine
       * when it should run.
       * @param visitor
       */
      PluginManager.prototype.addVisitor = function (visitor) {
          this.visitors.push(visitor);
      };
      /**
       * Adds a pre processor object
       * @param {object} preProcessor
       * @param {number} priority - guidelines 1 = before import, 1000 = import, 2000 = after import
       */
      PluginManager.prototype.addPreProcessor = function (preProcessor, priority) {
          var indexToInsertAt;
          for (indexToInsertAt = 0; indexToInsertAt < this.preProcessors.length; indexToInsertAt++) {
              if (this.preProcessors[indexToInsertAt].priority >= priority) {
                  break;
              }
          }
          this.preProcessors.splice(indexToInsertAt, 0, { preProcessor: preProcessor, priority: priority });
      };
      /**
       * Adds a post processor object
       * @param {object} postProcessor
       * @param {number} priority - guidelines 1 = before compression, 1000 = compression, 2000 = after compression
       */
      PluginManager.prototype.addPostProcessor = function (postProcessor, priority) {
          var indexToInsertAt;
          for (indexToInsertAt = 0; indexToInsertAt < this.postProcessors.length; indexToInsertAt++) {
              if (this.postProcessors[indexToInsertAt].priority >= priority) {
                  break;
              }
          }
          this.postProcessors.splice(indexToInsertAt, 0, { postProcessor: postProcessor, priority: priority });
      };
      /**
       *
       * @param manager
       */
      PluginManager.prototype.addFileManager = function (manager) {
          this.fileManagers.push(manager);
      };
      /**
       *
       * @returns {Array}
       * @private
       */
      PluginManager.prototype.getPreProcessors = function () {
          var preProcessors = [];
          for (var i_2 = 0; i_2 < this.preProcessors.length; i_2++) {
              preProcessors.push(this.preProcessors[i_2].preProcessor);
          }
          return preProcessors;
      };
      /**
       *
       * @returns {Array}
       * @private
       */
      PluginManager.prototype.getPostProcessors = function () {
          var postProcessors = [];
          for (var i_3 = 0; i_3 < this.postProcessors.length; i_3++) {
              postProcessors.push(this.postProcessors[i_3].postProcessor);
          }
          return postProcessors;
      };
      /**
       *
       * @returns {Array}
       * @private
       */
      PluginManager.prototype.getVisitors = function () {
          return this.visitors;
      };
      PluginManager.prototype.visitor = function () {
          var self = this;
          return {
              first: function () {
                  self.iterator = -1;
                  return self.visitors[self.iterator];
              },
              get: function () {
                  self.iterator += 1;
                  return self.visitors[self.iterator];
              }
          };
      };
      /**
       *
       * @returns {Array}
       * @private
       */
      PluginManager.prototype.getFileManagers = function () {
          return this.fileManagers;
      };
      return PluginManager;
  }());
  var pm;
  function PluginManagerFactory(less, newFactory) {
      if (newFactory || !pm) {
          pm = new PluginManager(less);
      }
      return pm;
  }

  var Parse = (function (environment, ParseTree, ImportManager) {
      var parse = function (input, options, callback) {
          if (typeof options === 'function') {
              callback = options;
              options = copyOptions(this.options, {});
          }
          else {
              options = copyOptions(this.options, options || {});
          }
          if (!callback) {
              var self_1 = this;
              return new Promise(function (resolve, reject) {
                  parse.call(self_1, input, options, function (err, output) {
                      if (err) {
                          reject(err);
                      }
                      else {
                          resolve(output);
                      }
                  });
              });
          }
          else {
              var context_1;
              var rootFileInfo = void 0;
              var pluginManager_1 = new PluginManagerFactory(this, !options.reUsePluginManager);
              options.pluginManager = pluginManager_1;
              context_1 = new contexts.Parse(options);
              if (options.rootFileInfo) {
                  rootFileInfo = options.rootFileInfo;
              }
              else {
                  var filename = options.filename || 'input';
                  var entryPath = filename.replace(/[^\/\\]*$/, '');
                  rootFileInfo = {
                      filename: filename,
                      rewriteUrls: context_1.rewriteUrls,
                      rootpath: context_1.rootpath || '',
                      currentDirectory: entryPath,
                      entryPath: entryPath,
                      rootFilename: filename
                  };
                  // add in a missing trailing slash
                  if (rootFileInfo.rootpath && rootFileInfo.rootpath.slice(-1) !== '/') {
                      rootFileInfo.rootpath += '/';
                  }
              }
              var imports_1 = new ImportManager(this, context_1, rootFileInfo);
              this.importManager = imports_1;
              // TODO: allow the plugins to be just a list of paths or names
              // Do an async plugin queue like lessc
              if (options.plugins) {
                  options.plugins.forEach(function (plugin) {
                      var evalResult;
                      var contents;
                      if (plugin.fileContent) {
                          contents = plugin.fileContent.replace(/^\uFEFF/, '');
                          evalResult = pluginManager_1.Loader.evalPlugin(contents, context_1, imports_1, plugin.options, plugin.filename);
                          if (evalResult instanceof LessError) {
                              return callback(evalResult);
                          }
                      }
                      else {
                          pluginManager_1.addPlugin(plugin);
                      }
                  });
              }
              new Parser(context_1, imports_1, rootFileInfo)
                  .parse(input, function (e, root) {
                  if (e) {
                      return callback(e);
                  }
                  callback(null, root, imports_1, options);
              }, options);
          }
      };
      return parse;
  });

  var lessRoot = (function (environment$1, fileManagers) {
      /**
       * @todo
       * This original code could be improved quite a bit.
       * Many classes / modules currently add side-effects / mutations to passed in objects,
       * which makes it hard to refactor and reason about.
       */
      environment$1 = new environment(environment$1, fileManagers);
      var SourceMapOutput = sourceMapOutput(environment$1);
      var SourceMapBuilder = sourceMapBuilder(SourceMapOutput, environment$1);
      var ParseTree = parseTree(SourceMapBuilder);
      var ImportManager = importManager(environment$1);
      var render = Render(environment$1, ParseTree);
      var parse = Parse(environment$1, ParseTree, ImportManager);
      var functions = Functions(environment$1);
      /**
       * @todo
       * This root properties / methods need to be organized.
       * It's not clear what should / must be public and why.
       */
      var initial = {
          version: [3, 11, 2],
          data: data,
          tree: tree,
          Environment: environment,
          AbstractFileManager: AbstractFileManager,
          AbstractPluginLoader: AbstractPluginLoader,
          environment: environment$1,
          visitors: visitors,
          Parser: Parser,
          functions: functions,
          contexts: contexts,
          SourceMapOutput: SourceMapOutput,
          SourceMapBuilder: SourceMapBuilder,
          ParseTree: ParseTree,
          ImportManager: ImportManager,
          render: render,
          parse: parse,
          LessError: LessError,
          transformTree: transformTree,
          utils: utils,
          PluginManager: PluginManagerFactory,
          logger: logger
      };
      // Create a public API
      var ctor = function (t) { return function () {
          var args = [];
          for (var _i = 0; _i < arguments.length; _i++) {
              args[_i] = arguments[_i];
          }
          return new (t.bind.apply(t, __spreadArrays([void 0], args)))();
      }; };
      var t;
      var api = Object.create(initial);
      for (var n in initial.tree) {
          /* eslint guard-for-in: 0 */
          t = initial.tree[n];
          if (typeof t === 'function') {
              api[n.toLowerCase()] = ctor(t);
          }
          else {
              api[n] = Object.create(null);
              for (var o in t) {
                  /* eslint guard-for-in: 0 */
                  api[n][o.toLowerCase()] = ctor(t[o]);
              }
          }
      }
      return api;
  });

  /* global window, XMLHttpRequest */
  var options;
  var logger$1;
  var fileCache = {};
  // TODOS - move log somewhere. pathDiff and doing something similar in node. use pathDiff in the other browser file for the initial load
  var FileManager = /** @class */ (function (_super) {
      __extends(FileManager, _super);
      function FileManager() {
          return _super !== null && _super.apply(this, arguments) || this;
      }
      FileManager.prototype.alwaysMakePathsAbsolute = function () {
          return true;
      };
      FileManager.prototype.join = function (basePath, laterPath) {
          if (!basePath) {
              return laterPath;
          }
          return this.extractUrlParts(laterPath, basePath).path;
      };
      FileManager.prototype.doXHR = function (url, type, callback, errback) {
          var xhr = new XMLHttpRequest();
          var async = options.isFileProtocol ? options.fileAsync : true;
          if (typeof xhr.overrideMimeType === 'function') {
              xhr.overrideMimeType('text/css');
          }
          logger$1.debug("XHR: Getting '" + url + "'");
          xhr.open('GET', url, async);
          xhr.setRequestHeader('Accept', type || 'text/x-less, text/css; q=0.9, */*; q=0.5');
          xhr.send(null);
          function handleResponse(xhr, callback, errback) {
              if (xhr.status >= 200 && xhr.status < 300) {
                  callback(xhr.responseText, xhr.getResponseHeader('Last-Modified'));
              }
              else if (typeof errback === 'function') {
                  errback(xhr.status, url);
              }
          }
          if (options.isFileProtocol && !options.fileAsync) {
              if (xhr.status === 0 || (xhr.status >= 200 && xhr.status < 300)) {
                  callback(xhr.responseText);
              }
              else {
                  errback(xhr.status, url);
              }
          }
          else if (async) {
              xhr.onreadystatechange = function () {
                  if (xhr.readyState == 4) {
                      handleResponse(xhr, callback, errback);
                  }
              };
          }
          else {
              handleResponse(xhr, callback, errback);
          }
      };
      FileManager.prototype.supports = function () {
          return true;
      };
      FileManager.prototype.clearFileCache = function () {
          fileCache = {};
      };
      FileManager.prototype.loadFile = function (filename, currentDirectory, options, environment) {
          // TODO: Add prefix support like less-node?
          // What about multiple paths?
          if (currentDirectory && !this.isPathAbsolute(filename)) {
              filename = currentDirectory + filename;
          }
          filename = options.ext ? this.tryAppendExtension(filename, options.ext) : filename;
          options = options || {};
          // sheet may be set to the stylesheet for the initial load or a collection of properties including
          // some context variables for imports
          var hrefParts = this.extractUrlParts(filename, window.location.href);
          var href = hrefParts.url;
          var self = this;
          return new Promise(function (resolve, reject) {
              if (options.useFileCache && fileCache[href]) {
                  try {
                      var lessText_1 = fileCache[href];
                      return resolve({ contents: lessText_1, filename: href, webInfo: { lastModified: new Date() } });
                  }
                  catch (e) {
                      return reject({ filename: href, message: "Error loading file " + href + " error was " + e.message });
                  }
              }
              self.doXHR(href, options.mime, function doXHRCallback(data, lastModified) {
                  // per file cache
                  fileCache[href] = data;
                  // Use remote copy (re-parse)
                  resolve({ contents: data, filename: href, webInfo: { lastModified: lastModified } });
              }, function doXHRError(status, url) {
                  reject({ type: 'File', message: "'" + url + "' wasn't found (" + status + ")", href: href });
              });
          });
      };
      return FileManager;
  }(AbstractFileManager));
  var FM = (function (opts, log) {
      options = opts;
      logger$1 = log;
      return FileManager;
  });

  // TODO: Add tests for browser @plugin
  /**
   * Browser Plugin Loader
   */
  var PluginLoader = /** @class */ (function (_super) {
      __extends(PluginLoader, _super);
      function PluginLoader(less) {
          var _this = _super.call(this) || this;
          _this.less = less;
          return _this;
          // Should we shim this.require for browser? Probably not?
      }
      PluginLoader.prototype.loadPlugin = function (filename, basePath, context, environment, fileManager) {
          return new Promise(function (fulfill, reject) {
              fileManager.loadFile(filename, basePath, context, environment)
                  .then(fulfill).catch(reject);
          });
      };
      return PluginLoader;
  }(AbstractPluginLoader));

  var LogListener = (function (less, options) {
      var logLevel_debug = 4;
      var logLevel_info = 3;
      var logLevel_warn = 2;
      var logLevel_error = 1;
      // The amount of logging in the javascript console.
      // 3 - Debug, information and errors
      // 2 - Information and errors
      // 1 - Errors
      // 0 - None
      // Defaults to 2
      options.logLevel = typeof options.logLevel !== 'undefined' ? options.logLevel : (options.env === 'development' ? logLevel_info : logLevel_error);
      if (!options.loggers) {
          options.loggers = [{
                  debug: function (msg) {
                      if (options.logLevel >= logLevel_debug) {
                          console.log(msg);
                      }
                  },
                  info: function (msg) {
                      if (options.logLevel >= logLevel_info) {
                          console.log(msg);
                      }
                  },
                  warn: function (msg) {
                      if (options.logLevel >= logLevel_warn) {
                          console.warn(msg);
                      }
                  },
                  error: function (msg) {
                      if (options.logLevel >= logLevel_error) {
                          console.error(msg);
                      }
                  }
              }];
      }
      for (var i_1 = 0; i_1 < options.loggers.length; i_1++) {
          less.logger.addListener(options.loggers[i_1]);
      }
  });

  var ErrorReporting = (function (window, less, options) {
      function errorHTML(e, rootHref) {
          var id = "less-error-message:" + extractId(rootHref || '');
          var template = '<li><label>{line}</label><pre class="{class}">{content}</pre></li>';
          var elem = window.document.createElement('div');
          var timer;
          var content;
          var errors = [];
          var filename = e.filename || rootHref;
          var filenameNoPath = filename.match(/([^\/]+(\?.*)?)$/)[1];
          elem.id = id;
          elem.className = 'less-error-message';
          content = "<h3>" + (e.type || 'Syntax') + "Error: " + (e.message || 'There is an error in your .less file') +
              ("</h3><p>in <a href=\"" + filename + "\">" + filenameNoPath + "</a> ");
          var errorline = function (e, i, classname) {
              if (e.extract[i] !== undefined) {
                  errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1))
                      .replace(/\{class\}/, classname)
                      .replace(/\{content\}/, e.extract[i]));
              }
          };
          if (e.line) {
              errorline(e, 0, '');
              errorline(e, 1, 'line');
              errorline(e, 2, '');
              content += "on line " + e.line + ", column " + (e.column + 1) + ":</p><ul>" + errors.join('') + "</ul>";
          }
          if (e.stack && (e.extract || options.logLevel >= 4)) {
              content += "<br/>Stack Trace</br />" + e.stack.split('\n').slice(1).join('<br/>');
          }
          elem.innerHTML = content;
          // CSS for error messages
          browser.createCSS(window.document, [
              '.less-error-message ul, .less-error-message li {',
              'list-style-type: none;',
              'margin-right: 15px;',
              'padding: 4px 0;',
              'margin: 0;',
              '}',
              '.less-error-message label {',
              'font-size: 12px;',
              'margin-right: 15px;',
              'padding: 4px 0;',
              'color: #cc7777;',
              '}',
              '.less-error-message pre {',
              'color: #dd6666;',
              'padding: 4px 0;',
              'margin: 0;',
              'display: inline-block;',
              '}',
              '.less-error-message pre.line {',
              'color: #ff0000;',
              '}',
              '.less-error-message h3 {',
              'font-size: 20px;',
              'font-weight: bold;',
              'padding: 15px 0 5px 0;',
              'margin: 0;',
              '}',
              '.less-error-message a {',
              'color: #10a',
              '}',
              '.less-error-message .error {',
              'color: red;',
              'font-weight: bold;',
              'padding-bottom: 2px;',
              'border-bottom: 1px dashed red;',
              '}'
          ].join('\n'), { title: 'error-message' });
          elem.style.cssText = [
              'font-family: Arial, sans-serif',
              'border: 1px solid #e00',
              'background-color: #eee',
              'border-radius: 5px',
              '-webkit-border-radius: 5px',
              '-moz-border-radius: 5px',
              'color: #e00',
              'padding: 15px',
              'margin-bottom: 15px'
          ].join(';');
          if (options.env === 'development') {
              timer = setInterval(function () {
                  var document = window.document;
                  var body = document.body;
                  if (body) {
                      if (document.getElementById(id)) {
                          body.replaceChild(elem, document.getElementById(id));
                      }
                      else {
                          body.insertBefore(elem, body.firstChild);
                      }
                      clearInterval(timer);
                  }
              }, 10);
          }
      }
      function removeErrorHTML(path) {
          var node = window.document.getElementById("less-error-message:" + extractId(path));
          if (node) {
              node.parentNode.removeChild(node);
          }
      }
      function removeError(path) {
          if (!options.errorReporting || options.errorReporting === 'html') {
              removeErrorHTML(path);
          }
          else if (options.errorReporting === 'console') ;
          else if (typeof options.errorReporting === 'function') {
              options.errorReporting('remove', path);
          }
      }
      function errorConsole(e, rootHref) {
          var template = '{line} {content}';
          var filename = e.filename || rootHref;
          var errors = [];
          var content = (e.type || 'Syntax') + "Error: " + (e.message || 'There is an error in your .less file') + " in " + filename;
          var errorline = function (e, i, classname) {
              if (e.extract[i] !== undefined) {
                  errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1))
                      .replace(/\{class\}/, classname)
                      .replace(/\{content\}/, e.extract[i]));
              }
          };
          if (e.line) {
              errorline(e, 0, '');
              errorline(e, 1, 'line');
              errorline(e, 2, '');
              content += " on line " + e.line + ", column " + (e.column + 1) + ":\n" + errors.join('\n');
          }
          if (e.stack && (e.extract || options.logLevel >= 4)) {
              content += "\nStack Trace\n" + e.stack;
          }
          less.logger.error(content);
      }
      function error(e, rootHref) {
          if (!options.errorReporting || options.errorReporting === 'html') {
              errorHTML(e, rootHref);
          }
          else if (options.errorReporting === 'console') {
              errorConsole(e, rootHref);
          }
          else if (typeof options.errorReporting === 'function') {
              options.errorReporting('add', e, rootHref);
          }
      }
      return {
          add: error,
          remove: removeError
      };
  });

  // Cache system is a bit outdated and could do with work
  var Cache = (function (window, options, logger) {
      var cache = null;
      if (options.env !== 'development') {
          try {
              cache = (typeof window.localStorage === 'undefined') ? null : window.localStorage;
          }
          catch (_) { }
      }
      return {
          setCSS: function (path, lastModified, modifyVars, styles) {
              if (cache) {
                  logger.info("saving " + path + " to cache.");
                  try {
                      cache.setItem(path, styles);
                      cache.setItem(path + ":timestamp", lastModified);
                      if (modifyVars) {
                          cache.setItem(path + ":vars", JSON.stringify(modifyVars));
                      }
                  }
                  catch (e) {
                      // TODO - could do with adding more robust error handling
                      logger.error("failed to save \"" + path + "\" to local storage for caching.");
                  }
              }
          },
          getCSS: function (path, webInfo, modifyVars) {
              var css = cache && cache.getItem(path);
              var timestamp = cache && cache.getItem(path + ":timestamp");
              var vars = cache && cache.getItem(path + ":vars");
              modifyVars = modifyVars || {};
              vars = vars || "{}"; // if not set, treat as the JSON representation of an empty object
              if (timestamp && webInfo.lastModified &&
                  (new Date(webInfo.lastModified).valueOf() ===
                      new Date(timestamp).valueOf()) &&
                  JSON.stringify(modifyVars) === vars) {
                  // Use local copy
                  return css;
              }
          }
      };
  });

  var ImageSize = (function () {
      function imageSize() {
          throw {
              type: 'Runtime',
              message: 'Image size functions are not supported in browser version of less'
          };
      }
      var imageFunctions = {
          'image-size': function (filePathNode) {
              imageSize();
              return -1;
          },
          'image-width': function (filePathNode) {
              imageSize();
              return -1;
          },
          'image-height': function (filePathNode) {
              imageSize();
              return -1;
          }
      };
      functionRegistry.addMultiple(imageFunctions);
  });

  //
  var root = (function (window, options) {
      var document = window.document;
      var less = lessRoot();
      less.options = options;
      var environment = less.environment;
      var FileManager = FM(options, less.logger);
      var fileManager = new FileManager();
      environment.addFileManager(fileManager);
      less.FileManager = FileManager;
      less.PluginLoader = PluginLoader;
      LogListener(less, options);
      var errors = ErrorReporting(window, less, options);
      var cache = less.cache = options.cache || Cache(window, options, less.logger);
      ImageSize(less.environment);
      // Setup user functions - Deprecate?
      if (options.functions) {
          less.functions.functionRegistry.addMultiple(options.functions);
      }
      var typePattern = /^text\/(x-)?less$/;
      function clone(obj) {
          var cloned = {};
          for (var prop in obj) {
              if (obj.hasOwnProperty(prop)) {
                  cloned[prop] = obj[prop];
              }
          }
          return cloned;
      }
      // only really needed for phantom
      function bind(func, thisArg) {
          var curryArgs = Array.prototype.slice.call(arguments, 2);
          return function () {
              var args = curryArgs.concat(Array.prototype.slice.call(arguments, 0));
              return func.apply(thisArg, args);
          };
      }
      function loadStyles(modifyVars) {
          var styles = document.getElementsByTagName('style');
          var style;
          for (var i_1 = 0; i_1 < styles.length; i_1++) {
              style = styles[i_1];
              if (style.type.match(typePattern)) {
                  var instanceOptions = clone(options);
                  instanceOptions.modifyVars = modifyVars;
                  var lessText_1 = style.innerHTML || '';
                  instanceOptions.filename = document.location.href.replace(/#.*$/, '');
                  /* jshint loopfunc:true */
                  // use closure to store current style
                  less.render(lessText_1, instanceOptions, bind(function (style, e, result) {
                      if (e) {
                          errors.add(e, 'inline');
                      }
                      else {
                          style.type = 'text/css';
                          if (style.styleSheet) {
                              style.styleSheet.cssText = result.css;
                          }
                          else {
                              style.innerHTML = result.css;
                          }
                      }
                  }, null, style));
              }
          }
      }
      function loadStyleSheet(sheet, callback, reload, remaining, modifyVars) {
          var instanceOptions = clone(options);
          addDataAttr(instanceOptions, sheet);
          instanceOptions.mime = sheet.type;
          if (modifyVars) {
              instanceOptions.modifyVars = modifyVars;
          }
          function loadInitialFileCallback(loadedFile) {
              var data = loadedFile.contents;
              var path = loadedFile.filename;
              var webInfo = loadedFile.webInfo;
              var newFileInfo = {
                  currentDirectory: fileManager.getPath(path),
                  filename: path,
                  rootFilename: path,
                  rewriteUrls: instanceOptions.rewriteUrls
              };
              newFileInfo.entryPath = newFileInfo.currentDirectory;
              newFileInfo.rootpath = instanceOptions.rootpath || newFileInfo.currentDirectory;
              if (webInfo) {
                  webInfo.remaining = remaining;
                  var css = cache.getCSS(path, webInfo, instanceOptions.modifyVars);
                  if (!reload && css) {
                      webInfo.local = true;
                      callback(null, css, data, sheet, webInfo, path);
                      return;
                  }
              }
              // TODO add tests around how this behaves when reloading
              errors.remove(path);
              instanceOptions.rootFileInfo = newFileInfo;
              less.render(data, instanceOptions, function (e, result) {
                  if (e) {
                      e.href = path;
                      callback(e);
                  }
                  else {
                      cache.setCSS(sheet.href, webInfo.lastModified, instanceOptions.modifyVars, result.css);
                      callback(null, result.css, data, sheet, webInfo, path);
                  }
              });
          }
          fileManager.loadFile(sheet.href, null, instanceOptions, environment)
              .then(function (loadedFile) {
              loadInitialFileCallback(loadedFile);
          }).catch(function (err) {
              console.log(err);
              callback(err);
          });
      }
      function loadStyleSheets(callback, reload, modifyVars) {
          for (var i_2 = 0; i_2 < less.sheets.length; i_2++) {
              loadStyleSheet(less.sheets[i_2], callback, reload, less.sheets.length - (i_2 + 1), modifyVars);
          }
      }
      function initRunningMode() {
          if (less.env === 'development') {
              less.watchTimer = setInterval(function () {
                  if (less.watchMode) {
                      fileManager.clearFileCache();
                      loadStyleSheets(function (e, css, _, sheet, webInfo) {
                          if (e) {
                              errors.add(e, e.href || sheet.href);
                          }
                          else if (css) {
                              browser.createCSS(window.document, css, sheet);
                          }
                      });
                  }
              }, options.poll);
          }
      }
      //
      // Watch mode
      //
      less.watch = function () {
          if (!less.watchMode) {
              less.env = 'development';
              initRunningMode();
          }
          this.watchMode = true;
          return true;
      };
      less.unwatch = function () { clearInterval(less.watchTimer); this.watchMode = false; return false; };
      //
      // Synchronously get all <link> tags with the 'rel' attribute set to
      // "stylesheet/less".
      //
      less.registerStylesheetsImmediately = function () {
          var links = document.getElementsByTagName('link');
          less.sheets = [];
          for (var i_3 = 0; i_3 < links.length; i_3++) {
              if (links[i_3].rel === 'stylesheet/less' || (links[i_3].rel.match(/stylesheet/) &&
                  (links[i_3].type.match(typePattern)))) {
                  less.sheets.push(links[i_3]);
              }
          }
      };
      //
      // Asynchronously get all <link> tags with the 'rel' attribute set to
      // "stylesheet/less", returning a Promise.
      //
      less.registerStylesheets = function () { return new Promise(function (resolve, reject) {
          less.registerStylesheetsImmediately();
          resolve();
      }); };
      //
      // With this function, it's possible to alter variables and re-render
      // CSS without reloading less-files
      //
      less.modifyVars = function (record) { return less.refresh(true, record, false); };
      less.refresh = function (reload, modifyVars, clearFileCache) {
          if ((reload || clearFileCache) && clearFileCache !== false) {
              fileManager.clearFileCache();
          }
          return new Promise(function (resolve, reject) {
              var startTime;
              var endTime;
              var totalMilliseconds;
              var remainingSheets;
              startTime = endTime = new Date();
              // Set counter for remaining unprocessed sheets
              remainingSheets = less.sheets.length;
              if (remainingSheets === 0) {
                  endTime = new Date();
                  totalMilliseconds = endTime - startTime;
                  less.logger.info('Less has finished and no sheets were loaded.');
                  resolve({
                      startTime: startTime,
                      endTime: endTime,
                      totalMilliseconds: totalMilliseconds,
                      sheets: less.sheets.length
                  });
              }
              else {
                  // Relies on less.sheets array, callback seems to be guaranteed to be called for every element of the array
                  loadStyleSheets(function (e, css, _, sheet, webInfo) {
                      if (e) {
                          errors.add(e, e.href || sheet.href);
                          reject(e);
                          return;
                      }
                      if (webInfo.local) {
                          less.logger.info("Loading " + sheet.href + " from cache.");
                      }
                      else {
                          less.logger.info("Rendered " + sheet.href + " successfully.");
                      }
                      browser.createCSS(window.document, css, sheet);
                      less.logger.info("CSS for " + sheet.href + " generated in " + (new Date() - endTime) + "ms");
                      // Count completed sheet
                      remainingSheets--;
                      // Check if the last remaining sheet was processed and then call the promise
                      if (remainingSheets === 0) {
                          totalMilliseconds = new Date() - startTime;
                          less.logger.info("Less has finished. CSS generated in " + totalMilliseconds + "ms");
                          resolve({
                              startTime: startTime,
                              endTime: endTime,
                              totalMilliseconds: totalMilliseconds,
                              sheets: less.sheets.length
                          });
                      }
                      endTime = new Date();
                  }, reload, modifyVars);
              }
              loadStyles(modifyVars);
          });
      };
      less.refreshStyles = loadStyles;
      return less;
  });

  /**
   * Kicks off less and compiles any stylesheets
   * used in the browser distributed version of less
   * to kick-start less using the browser api
   */
  var options$1 = defaultOptions();
  if (window.less) {
      for (var key in window.less) {
          if (window.less.hasOwnProperty(key)) {
              options$1[key] = window.less[key];
          }
      }
  }
  addDefaultOptions(window, options$1);
  options$1.plugins = options$1.plugins || [];
  if (window.LESS_PLUGINS) {
      options$1.plugins = options$1.plugins.concat(window.LESS_PLUGINS);
  }
  var less = root(window, options$1);
  window.less = less;
  var css;
  var head;
  var style;
  // Always restore page visibility
  function resolveOrReject(data) {
      if (data.filename) {
          console.warn(data);
      }
      if (!options$1.async) {
          head.removeChild(style);
      }
  }
  if (options$1.onReady) {
      if (/!watch/.test(window.location.hash)) {
          less.watch();
      }
      // Simulate synchronous stylesheet loading by hiding page rendering
      if (!options$1.async) {
          css = 'body { display: none !important }';
          head = document.head || document.getElementsByTagName('head')[0];
          style = document.createElement('style');
          style.type = 'text/css';
          if (style.styleSheet) {
              style.styleSheet.cssText = css;
          }
          else {
              style.appendChild(document.createTextNode(css));
          }
          head.appendChild(style);
      }
      less.registerStylesheetsImmediately();
      less.pageLoadFinished = less.refresh(less.env === 'development').then(resolveOrReject, resolveOrReject);
  }

  return less;

})));