txt: ## dist_zef-finanalyst-Collection.md
  ## Chunk 1 of 2
  ```
      # Raku Collection Module
  
  ```
  
  > **DESCRIPTION** # DESCRIPTION
  > Software to collect content files written in Rakudoc (aka POD6) and render them in a chosen format. Extensive use is made of plugins to customise the rendering. A distinction is made between the Rakudoc files for the main content (sources) and the Rakudoc files that describe the whole collection of sources (mode-sources), eg. the landing page (*index.html*) of a website, or the Contents page of the same sources in book form. The collection process is in stages at the start of which plugin callables (Raku programs) can be added that transform intermediate data or add templates, or add new Pod::Blocks for the rendering.
  
  > **AUTHOR** # AUTHOR
  > Richard Hainsworth aka finanalyst
  
  ---
  
  ## Table of Contents
  
  [Installation](#installation)  
  [Usage](#usage)  
  [Life cycle of processing](#life-cycle-of-processing)  
  [Modes](#modes)  
  [Milestones](#milestones)  
  [Stopping or dumping information at milestones](#stopping-or-dumping-information-at-milestones)  
  [Source Milestone](#source-milestone)  
  [Mode Milestone](#mode-milestone)  
  [Setup Milestone](#setup-milestone)  
  [Render Milestone](#render-milestone)  
  [Compilation Milestone](#compilation-milestone)  
  [Transfer Milestone](#transfer-milestone)  
  [Report Milestone](#report-milestone)  
  [Completion Milestone](#completion-milestone)  
  [Collection Structure](#collection-structure)  
  [Collection Content](#collection-content)  
  [Extra assets (images, videos, etc)](#extra-assets-images-videos-etc)  
  [Cache](#cache)  
  [Mode](#mode)  
  [Templates](#templates)  
  [Configuration](#configuration)  
  [Top level configuration](#top-level-configuration)  
  [Mode-level configuration](#mode-level-configuration)  
  [Plugin level configuration](#plugin-level-configuration)  
  [Control flags](#control-flags)  
  [Plugin management](#plugin-management)  
  [Disabling a plugin](#disabling-a-plugin)  
  [Plugin types](#plugin-types)  
  [Setup](#setup)  
  [Render](#render)  
  [Compilation](#compilation)  
  [Transfer](#transfer)  
  [Report](#report)  
  [Completion](#completion)  
  [Plugin development](#plugin-development)  
  [Collection plugin specification](#collection-plugin-specification)  
  [Collection plugin tests](#collection-plugin-tests)  
  [Plugin updating](#plugin-updating)  
  [Mapping released plugins to mode directories](#mapping-released-plugins-to-mode-directories)  
  [Released plugins directory](#released-plugins-directory)  
  [Refresh process](#refresh-process)  
  [CLI Plugin Management System](#cli-plugin-management-system)  
  [Problems and TODO items](#problems-and-todo-items)  
  [Archiving and Minor Changes](#archiving-and-minor-changes)  
  [Dump file formatting](#dump-file-formatting)  
  [Post-cache methods](#post-cache-methods)  
  [multi method add(Str $fn, Array $p --> Pod::From::Cache )](#multi-method-addstr-fn-array-p----podfromcache-)  
  [multi method mask(Str $fn --> Pod::From::Cache)](#multi-method-maskstr-fn----podfromcache)  
  [multi method add-alias(Str $fn, Str :alias! --> Pod::From::Cache)](#multi-method-add-aliasstr-fn-str-alias----podfromcache)  
  [method behind-alias(Str $fn --> Str )](#method-behind-aliasstr-fn----str-)  
  [method pod(Str $fn)](#method-podstr-fn)  
  [multi method last-version( @version-data )](#multi-method-last-version-version-data-)  
  [Head](#head)  
  [Asset-cache methods](#asset-cache-methods)  
  [Copyright and License](#copyright-and-license)
  
  ---
  
  This module is used by the module **Collection-Raku-Documentation**, but is intended to be more general, such as building a personal site.
  
  # Installation
  
  To install the distribution, a refresh utility (see [Plugin refreshing](Plugin refreshing.md)), and the default plugin directory (see [Released plugin directory](Released plugin directory.md)), use
  
  ```
  zef install Collection
  
  ```
  
  For those who really want to have a non-default plugin directory, it is possible. But **warning**: extra user input will be needed for other utilities, so read the whole of this file), eg, to have a hidden directory `.Collection` in the home directory (under \*nix), use
  
  ```
  PluginPath=~/.Collection zef install Collection
  
  ```
  
  # Usage
  
  The Collection module expects there to be a `config.raku` file in the root of the collection, which provides information about how to obtain the content (Pod6/rakudoc> sources, a default Mode to render and output the collection. All the configuration, template, and plugin files described below are **Raku** programs that evaluate to a Hash. They are described in the documentation for the `RakuConfig` module.
  
  A concrete example of `Collection` is the [Collection-Raku-Documentation (CRD)](https://github.com/finanalyst/collection-raku-documentation.git) module. *CRD* contains a large number of plugins (see below). Some plugin examples are constructed for the extended tests. Since the test examples files are deleted by the final test, try:
  
  ```
  NoDelete=1 prove6 -I. xt
  
  ```
  
  and then look at eg., `xt/test-dir`.
  
  The main subroutine is `collect`. It requires a file `config.raku` to be in the `$CWD` (current working directory). In *CRD* the executable `Raku-Doc` initiates the collection by setting up sources and installing a `config.raku` file. It is then simply a command line interface to `collect`.
  
  # Life cycle of processing
  
  The content files are processed in several stages separated by milestones. At each milestone, intermediary data can be processed using plugin callables, the data after the plugin callables can be dumped, or the processed halted.
  
  `collect` can be called with option flags, which have the same effect as configuration options. The run-time values of the [Control flags](Control flags.md) take precedence over the configuration options.
  
  `collect` should be called with a [Mode](Mode.md). A **Mode** is the name of a set of configuration files, templates, and plugins that control the way the source files are processed and rendered. The main configuration file must contain a key called `mode`, which defines the default mode that `collect` uses if called with no explicit mode, so if `collect` is called without a **Mode**, the default will be used.
  
  # Modes
  
  A Mode:
  
  * is the name of the process by which a *Collection* is rendered and presented. At present, only `Website` is implemented, but it is planned to have Modes for `epub` and `pdf` formats. The presentation may be serving HTML files locally, or the creation of a single epub file for publishing.
  * is the name of a sub-directory under the Collection directory.
  * may not be named with any '\_' in it. This allows for sub-directories in a Collection folder that are not modes, eg., a Raku documentation repository
  * A Mode sub-directory must contain:
  
    * a sub-directory `configs`, and/or a `config.raku` file.
  
  # Milestones
  
  The `collect` sub can be called once the collection directory contains a `config.raku`, which in turn contains the location of a directory of rakudoc source files, which must contain recursively at least one source.
  
  Processing occurs during a stage named by the milestone which starts it. Each stage is affected by a set of [Control flags](Control flags.md). Certain flags will be passed to the underlying objects, eg. `RakuConfig` and `ProcessedPod` (see `Raku::Pod::Render`).
  
  Plugin callables may be called at each milestone (except 'Source' and 'Mode', where they are not defined). Plugins are described in more detail in [Plugin management](Plugin management.md). plugin callables are milestone specific, with the call parameters and return values depending on the milestone.
  
  The milestones are:
  
  * Source
  * Mode
  * Setup
  * Render
  * Compilation
  * Transfer
  * Report
  * Completion
  
  ## Stopping or dumping information at milestones
  
  Intermediate data can be dumped at the milestone **without stopping** the processing, eg.,
  
  ```
  collect(:dump-at<source render>);
  
  ```
  
  Alternatively, the processing can be **stopped** and intermediate data inspected, EITHER after the stage has run, but before the plugin callables for the next stage have been triggered, eg.,
  
  ```
  my $rv = collect(:after<setup>);
  
  ```
  
  OR after the previous stage has run and after the plugin callables for the milestone have been triggered, eg.,
  
  ```
  my $rv = collect(:before<render>);
  
  ```
  
  The return value `$rv` is an array of the objects provided to plugin callables at that milestone, and an array of the plugin callables triggered (note the plugin callables used will be a difference between the `:before` and `:after` stop points). The plugins-used array is not provided to all plugin callables, except at the Report milestone.
  
  The return value `$rv` at `:after` will contain the object provided by the milestone after the named milestone. For example, milestone milestone 'Setup' is followed by milestone 'Render'. The return object for `:after<setup>` will be the return object for milestone 'Render'. See Milestones for more information.
  
  The object returned by `:before<render>` may be affected by the plugin callables that are triggered before the named stage.
  
  The `:before`, `:after` and `:dump-at` option values are the (case-insensitive) name(s) of the inspection point for the milestone. `:before` and `:after` only take one name, but `:dump-at` may take one or all of them in a space-delimited unordered list.
  
  The `dump-at` option calls `.raku` [TODO pretty-dump, when it handles BagHash and classes] on the same objects as above and then outputs them to a file(s) called `dump-at-<milestone name>.txt`.
  
  ## Source Milestone
  
  (Skipped if the `:without-processing` flag is True)
  
  Since this is the start of the processing, no plugins are defined as there are no objects for them to operate on.
  
  The `config.raku` file must exist and must contain a minimum set of keys. It may optionally contain keys for the control flags that control the stage, see below. The intent is to keep the options for the root configuration file as small as possible and only refer to the source files. Most other options are configured by the Mode.
  
  During the subsequent **Source** stage, the source files in the collection are brought in, if the collection has not been fully initiated, using the `source-obtain` configaturation list. Alternatively, any updates are brought in using the `source-refresh` list. Commonly, sources will be in a *git* repository, which has separate commands for `clone` and `pull`. If the `source-obtain` and `source-refresh` options are not given (for example during a test), no changes will be made to the source directory.
  
  Any changes to the source files are cached by default.
  
  The control flags for this stage are:
  
  * **no-refresh** (default False)
  
  Prevents source file updates from being brought in.
  
  * **recompile**
  
  Forces all the source files to be recompiled into the cache.
  
  ## Mode Milestone
  
  (Skipped if the `:without-processing` flag is True)
  
  Collection makes a distinction between Rakudoc source files that are the main content, and the source files needed to integrate the main content into a whole. The integration sources will differ according to the final output. For example, a book may have a Foreward, a Contents, a Glossary, etc, whilst a website will have a landing page (eg., *index.html*), and perhaps other index pages for subsections. A book may also organise content into sections that depend on metadata in the source files. A book will have a defined order of sections, but a website has no order. A website will require CSS files and perhaps jQuery scripts to be associated with Blocks. A book will have different formating requirements for pages.
  
  These differences are contained in the **mode** configuration, and the plugins and templates for the mode.
  
  At this milestone, the source files have been cached. The **mode** sub-directory has not been tested, and the configuration for the mode has not been used. Since plugin management is dependent on the mode configuration, no plugin callables can be called.
  
  The **return value** of `collect` with `:after<source>` is a single `Pod::From::Cache` object that does a `Post-Cache` role (see below for `Post-Cache` methods).
  
  A `Pod::From::Cache` object provides a list of updated files, and a full set of source files. It will provide a list of Pod::Blocks contained in each content files, using the filename as the key.
  
  During the stage the source files for the Mode are obtained, compiled and cached. The process is controlled by the same options as the *Source* stage. For example, the **Mode** for `Collection-Raku-Documentation` is *Website*.
  
  If a sub-directory with the same name as *mode* does not exist, or there are no config files in the `<mode>/config` directory, `collect` will throw an `X::Collection::NoMode` exception at the start of the stage.
  
  Mode source files are stored under the mode sub-directory and cached there. If the mode source files are stored remotely and updated independently of the collection, then the `mode-obtain` and `mode-refresh` keys are used.
  
  ## Setup Milestone
  
  (Skipped if the `:without-processing` flag is True)
  
  If **setup** plugin callables are defined and in the mode's plugins-required list, then the cache objects for the sources and the mode's sources (and the **full-render** value) are passed to the program defined by the plugin's **setup** key.
  
  The purpose of this milestone is to allow for content files to be pre-processed, perhaps to creates several sub-files from one big file, or to combine files in some way, or to gather information for a search algorithm.
  
  During the setup stage,
  
  * the `ProcessedPod` object is prepared,
  * templates specified in the `templates` directory are added
  * the key **mode-name** is added to the `ProcessedPod` object's plugin-data area and given the value of the mode.
  
  The Setup stage depends on the following options:
  
  * **full-render**
  
  By default, only files that are changed are re-rendered, which includes an assumption that if any source file is changed, then all the **mode** sources must be re-rendered as well. (See the Problems section below for a caveat.)
  
  When **full-render** is True, the output directory is emptied of content, forcing all files to be rendered.
  
  **full-render** may be combined with **no-refresh**, for example when templates or plugins are changed and the aim is to see what effect they have on exactly the same sources. In such a case, the cache will not be changed, but the cache object will not contain any files generated by **setup** plugin callables.
  
  ## Render Milestone
  
  (Skipped if the `:without-processing` flag is True)
  
  At this milestone `render` plugins are supplied to the `ProcessedPod` object. New Pod::Blocks can be defined, and the templates associated with them can be created.
  
  The source files (by default only those that have been changed) are rendered.
  
  The stage is controlled by the same options as *Setup* and
  
  * with-only - affects which Documents are rendered, see Configuration for more
  * ignore - prevents docs from being Cached, see Configuration for more
  
  ## Compilation Milestone
  
  (Skipped if the `:without-processing` flag is True)
  
  During the stage after this milestone, the structure documents are rendered. They can have Pod-blocks which use data included by templates and plugins during the render stage. They can also add to data, which means that the order in which a plugin is called may be important.
  
  At this milestone plugin callables are provided to add compiled data to the `ProcessedPod` object, so that the sources in the mode's directory can function.
  
  During the **Render** stage, the `%processed` hash is constructed whose keys are the filenames of the output files, and whose values are a hash of the page components of each page.
  
  The `compilation` plugin callables could, eg, collect page component data (eg., Table of Contents, Glossaries, Footnotes), and write them into the `ProcessedPod` object separately so there is a TOC, Glossary, etc structure whose keys are filenames.
  
  The return value of `collect` at the inspection point is a list of `ProcessedPod`, `%process`, with the `ProcessedPod` already changed by the `compilation` plugin callables.
  
  The stage is controlled by the same options as *Setup* and
  
  * with-only - same as include but for structure documents
  * ignore-mode - as for ignore above
  
  ## Transfer Milestone
  
  (Skipped if the `:without-processing` flag is True)
  
  Plugins may generate assets that are not transfered by them, or it is important to ensure that a plugin runs after all other plugins.
  
  In addition, render plugins may create files that are transfered at the render stage, but should be removed after all plugins have run. So a transfer milestone plugin can be created to clean up the plugin's local directory.
  
  ## Report Milestone
  
  (Skipped if the `:without-processing` flag is True)
  
  Once a collection has been rendered, all the links between files, and to outside targets can be subjected to tests. It is also possible to subject all the rendered files to tests. This is accomplished using `report` plugin callables.
  
  In addition, all the plugin callables that have been used at each stage (except for the Report stage itself) are listed. The aim is to provide information for debugging.
  
  The report stage is intended for testing the outputs and producing reports on the tests.
  
  ## Completion Milestone
  
  Once the collection has been tested, it can be activated. For example, a collection could be processed into a book, or a `Cro` App run that makes the rendered files available on a browser. This is done using `completion` plugin callables.
  
  The **without-completion** option allows for the completion phase to be skipped.
  
  Setting **without-processing** to True and **without-completion** to True should have no effect unless
  
  * there are no caches, which will be the case the first time `collect` is run
  * the destination directory is missing, which will be the case the first time `collect` is run
  
  # Collection Structure
  
  A distribution contains content files, which may be updated on a regular basis, a cache, templates, extra assets referenced in a content file (such as images), and one or more modes.
  
  ## Collection Content
  
  The content of the distribution is contained in **rakudoc** files. In addition to the source files, there are Collection content files which express things like the Table of Contents for the whole collection.
  
  Collection content are held separately to the source content, so that each mode may have different pages.
  
  This allows for active search pages for a Website, not needed for an epub, or publisher data for an output formation that will be printed.
  
  ## Extra assets (images, videos, etc)
  
  Assets such as images, which are directly referenced in content file, but exist in different formats, eg, png, are held apart from content Pod6 files, but are processed with content files.
  
  The reasoning for this design is that Pod6 files are compiled and cached in a manner that does not suit image files. But when an image file is processed for inclusion in a content file, the image may need to be processed by the template (eg., image effects specified in a Pod Block config).
  
  The assets are all held in the same directory, specified by the configuration key `asset-basenamme`, but each asset may exist in subdirectories for each type of asset, specified by the `asset-paths` key.
  
  (Asset files relating to the rendering of a content file, such as css, javascript, etc, are managed by plugins, see below for more on plugins.)
  
  A class to manage asset files is added to the `ProcessedPod` object with a role, so the assets can be manipulated by plugins and templates. Assets that are in fact used by a Pod content file are marked as used. The aim of this functionality is to allow for report-stage plugin callables to detect whether all images have been used.
  
  Plugins can also transform the assets, and create new files in the ProcessedPod object for inclusion in the output.
  
  At the end of the compilation stage, all the assets that have been used are written to a directory specified in the Mode configuration file. It is the task of the template rendering block to ensure that the path where the asset is stored is the same as the path the final output (eg. the browser rendering html files) processor requests.
  
  In keeping with the principle that collection level meta data is kept in the top-level config file, and output data is associated with the specific mode, there are two asset-path definitions.
  
  * Collection level assets. The source of assets is kept in the top-level `config.raku` file. In order to have each asset in its own directory, the following is possible:
  
  ```
  ...
  :asset-basename<assets>,
  asset-paths => %(
      image => %(
          :directory<images>,
          :extensions<png jpeg jpeg svg>,
      ),
      video-clips => %(
          :directory<videos>,
          :extensions<mp4 webm>,
      ),
  ),
  ...
  
  ```
  
  Notice that the `type`, eg. *image* and *video-clips* above, are arbitrary and not dependent on the actual format.
  
  * Output configuration. The output destination is kept in the mode configuration, eg., `Website/configs/03-images.raku` contains
  
  ```
  %(
      :asset-out-path<html/assets>
      ),
  )
  
  ```
  
  For more see [Asset-cache methods](Asset-cache methods.md)
  
  ## Cache
  
  The **cache** is a Precomp structure into which the content files are pre-preprocessed.
  
  ## Mode
  
  The **Mode** is the collection of templates and configuration for some output. A collection may contain multiple Modes, each in their own subdirectory.
  
  The default Mode for **Collection-Raku-Documentation** is **Website**, for example.
  
  The string defining `mode` must refer to an immediate directory of the root of the collection, so it is compared to `/ ^ \W+ (\w+) '/'? .* $ /` and only the inner `\w` chars are used.
  
  The templates, configuration, output files, and other assets used by a Mode are associated with the Mode, and should reside beneath the Mode sub-directory.
  
  ## Templates
  
  The **templates**, which may be any format (currently RakuClosure or Mustache) accepted by `ProcessedPod`, define how the following are expressed in the output:
  
  * the elements of the content files, eg. paragraphs, headers
  * the files as entities, eg, whether as single files, or chapters of a book
  * the collective components of content files, viz, Table of Contents, footnotes, Glossary, Meta data
  * All the templates may be in one file, or distributed between files.
  
    * If there are no templates in the directory, the default files in `ProcessedPod` are used.
    * If there are multiple files in the directory, they will all be evaluated in alphanumeric order. Note that existing keys will be over-written if they exist in later templates. This is **not** the same behaviour as for Configuration files.
  
  # Configuration
  
  There are three levels of configuration:
  
  * The top-level configuration resides in `config.raku` in the root directory of the Collection. The `collect` sub will fail without this file.
  * The Mode configuration typically resides in the `configs` directory, in several files (the names are not important).
  * Each plugin has its own config, in the `config.raku` file of its directory.
  
  ## Top level configuration
  
  In the descriptions below, simple illustrative names are given to files with configuration, templates, callables. These files are generally **Raku** programs, which are compiled and run. They will almost certainly contain errors during development and the **Rakudo** compiler will provide information based on the filename. So it is good practice to name the files that make them easier to locate, such as prefixing them with the plugin name.
  
  `config.raku` **must** contain the following keys:
  
  * the **cache** directory, relative to the root directory of the collection
  
    * `Collection-Raku-Documentation` default: 'doc-cache',
  * the **sources** directory, relative to the root of the collection and must contain at least one content file
  
    * `Collection-Raku-Documentation` default: 'raku-docs'
  * **mode** is the default mode for the collection, and must be a sub-directory, which must exist and contain a `configs` sub-directory (note the plural ending). See Mode level configuration below.
  
    * `Collection-Raku-Documentation` default: 'Website'
  * **without-processing** as described in Milestones
  
    * default: False
  * **no-refresh** as described in Milestones
  
    * default: False
  * **recompile** as described in Milestones
  
    * default: False
  
  The following are optional keys, together with the defaults
  
  * the allowed **extensions** for content files. These are provided to the `Pod::From::Cache` object.
  
    * default: < rakudoc pod pod6 p6 pm pm6 >
  * no-status This option controls whether a progress bar is provided in the terminal
  
    * default: False
  * **source-obtain** is the array of strings sent to the OS by `run` to obtain sources, eg git clone and assumes CWD is set to the directory of collection. Without this key, there must already be files in `sources`.
  
    * default: ()
  * **source-refresh** is the array of strings run to refresh the sources, assumes CWD set to the directory of sources. No key assumes the sources never change.
  
    * default: ()
  * **ignore** is a list of files in the **sources** directory that are not cached. This is a Collection level configuration. The option **include-only** is Mode level configuration, see below.
  
    * default: ()
  * **no-status** as described in Milestones
  
    * default: False
  * **without-report** as described in Milestones
  
    * default: False
  * **full-render** as described in Milestones
  
    * default: False
  * **asset-basename** as described in [Asset-cache methods](Asset-cache methods.md)
  
    * `Collection-Raku-Documentation` default: 'asset\_base'
  
  ## Mode-level configuration
  
  The mode-level configuration resides in one or more **files** that are under the **configs/** sub-directory of the `mode` directory. This arrangement is used to allow for configuration to be separated into different named files for ease of management.
  
  The following rules apply:
  
  * If the **configs** directory for a mode does not exist or is empty, **Raku-Doc** (`collect` sub) will fail.
  * The Configuration consists of one or more `Raku` files that each evaluate to a hash.
  
    * Each Config file in the **Configs** directory will be evaluated in alphabetical order.
    * Configuration keys may not be over-written. An `X::RakuConfig::OverwriteKey` exception will be thrown if an attempt is made to redefine a key.
  
  All the following keys are mandatory. Where a key refers to a directory (path), it should normally be relative to the `mode` sub-directory.
  
  * **mode-sources** location of the source files for the Collection pages, eg., TOC.
  * **mode-cache** location of the cache files
  * the **templates** subdirectory, which must contain raku files as described in `ProcessedPod`. These are all passed at the **Render** milestone directly to the `ProcessedPod` object.
  * **destination** directory where the output files are rendered
  * **report-path** is the path to which `report` plugins should output their reports.
  * **plugin-format** defines the format the plugins relate to. Each Mode is specified to produce output in a specific format, and the plugins, which include templates, are related to the format. Published plugins are stored for a particular format.
  * **plugins-required** points to a hash whose keys are milestone names where plugin callables can be applied
  
    * **setup** a list of plugin names, see [Plugin management](Plugin management.md), for pre-processing cache contents
    * **render** plugins used to render Pod::Blocks
    * **compilation** plugins prepare the `ProcessedPod` object for collection pages.
    * **assets** plugins that mark assets created in previous milestones
    * **report** plugins to test and report on the rendering process
    * **completion** plugins that define what happens after rendering
    * **cleanup** plugins if cleanup is needed.
  * **landing-place** is the name of the file that comes first during the completion stage. For example, in a Website, the landing file is usually called `index.html`
  * **output-ext** is the extension for the output files
  * **plugin-options** is mandatory, see [Plugin level configuration](Plugin level configuration.md) for more information
  
  All optional control flags are False by default. For the Mode configuration they are:
  
  * no-status
  * full-render
  * without-completion
  * without-report
  * no-preserved-state
  * debug-when
  * verbose-when
  * no-code-escape
  
  ## Plugin level configuration
  
  Each plugin has its own configuration (more information in the sections on Plugins). In addition to the mandatory keys, a plugin may have its own configuration data. The configuration data in the plugin directory will be over-written each time a plugin is updated.
  
  In order to provide for preservation of configuration data at the Mode level, the key `plugin-options` (typically kept in a separate config file) is used. The value of `plugin-options` is a Hash whose keys are the names of plugins. Each plugin-name key has a value that is a Hash of the keys required by the plugin.
  
  For example, the `Collection-Raku-Documentation` plugin `cro-app` has the configuration options `:port` and `:host`. The default `Collection-Raku-Documentation` configuration contains the snippet:
  
  ```
  plugin-options => %(
      cro-app => %(
          :port<30000>,
          :host<localhost>,
      ),
  ),
  
  ```
  
  in a file under the Mode's `configs/` directory. These values will over-ride the plugin's default config values.
  
  The plugin should therefore take configuration data from the ProcessedPod instance and not from the config file it is distributed with. This means that if a new plugin is intended to be used in place of an pre-existing one (see [Refresh process](Refresh process.md)), then the developer needs to check the configuration information from the namespace of the replaced name.
  
  The Setup and Completion plugins are passed `plugin-options` directly because the ProcessedPod instance is out of scope.
  
  `plugin-options` is a mandatory option in the Mode configuration. It may be set to Empty, viz.,
  
  ```
  plugin-options()
  
  ```
  
  in which case, all plugins will use their default options.
  
  The ProcessPod instance is only modified by `Render` plugins, so if there is plugin configuration data that is needed by another Milestone callable, the plugin should call a blank callable, with empty block and templates.
  
  # Control flags
  
  The control flags are also covered in [Milestones](Milestones.md). Control flags by default are False.
  
  * **no-status**
  
  No progress status is output at any time.
  
  * **without-processing**
  
  Setting **without-processing** to True will skip all the stages except **Completion**, so long as the destination directories exist.
  
  * **no-preserved-state**
  
  In order to allow for changes in some source files, or in only mode files, after all the sources have been processed once, the processing state must be archived. This may not be needed in testing or if the archiving takes too long.
  
  Setting no-preserved-state = True prevents storage of state, but also forces **without-processing** to False, and **recompile** to True.
  
  * **recompile**
  
  Controls the updating and caching of the content files. If true, then all files will be recompiled and cached.
  
  A True value is over-ridden by **without-processing**
  
  Normally False, which allows for only changed files to be processed.
  
  * **no-refresh**
  
  Prevents the updating of content files, so no changes will be made.
  
  * **full-render**
  
  Forces all files to be rendered. Even if there are no changes to source files, plugins or templates may be added/changed, thus changing the output, so all files need to be re-rendered.
  
  This flag is set to False if **without-processing** is True.
  
  * **without-report**
  
  Normally, report plugin callables report on the final state of the output files. This flag prevents report plugin callables from being loaded or run.
  
  If **without-processing** is set, then the **Report** stage is skipped. If, however, the caches do not exist (deleted or first run), then the value of **without-processing** is ignored and the value of **without-report** is observed.
  
  * **debug-when & verbose-when**
  
  ProcessedPod uses `debug` and `verbose`, which provide information about which blocks are processed (debug), and the result after the application of the template (verbose). This is a lot of information and generally, it is only a few files that are of interest.
  
  These two flags take a string, eg., `:debug-when<Introduction.pod6>` or `:debug-when<101 about>` , and when the string matches the filename, then the debug/verbose flag is set for that file only.
  
  Note `verbose` is **only** effective when `debug` is True.
  
  * **collection-info**
  
  Causes collect to produce information about milestones and valid and invalid plugins
  
  * **with-only** filename
  
  Collect is run only with that filename, which must be in the sources or mode-sources, and is specified like `debug-when`.
  
  The option takes a string containing the filename. An empty string means all filenames in sources and mode-sources.
  
  * **no-code-escape**
  
  `ProcessedPod` has a special flag for turning off escaping in code sections when a highlighter is used to pre-process code. In some cases, the highlighter also does HTML escaping, so RPR has to avoid it.
  
  This has to be done at the Mode level and not left to `render` plugin callables.
  
  # Plugin management
  
  Plugin callables are **Raku** programs that are executed at specific milestones in the rendering process. The milestone names are given in [Milestones](Milestones.md) above.
  
  The **plugins-required** key in the Mode's configuration contains a hash with keys whose names are the milestone names. Each key points to a list of plugin names, which are called in the order given.
  
  All plugins must reside within the mode **plugins**.
  
  All plugin names **must** be the name of a sub-directory under the **plugins** subdirectory. Within each plugin sub-directory, there must be a `config.raku` file containing information for the plugin, and for `Collection`. If *no* `config.raku` files exists, the plugin is not valid and will be skipped.
  
  With the exception of 'render' plugin callables, the config file must contain a key for the milestone type, which points to the program to be called, and when the file is evaluated, it yields a subroutine that takes the parameters needed for the plugin of that milestone. If no key exists with the name of the milestone, then the plugin is not valid.
  
  Plugin's may need other configurable data, which should be kept in the config file for the plugin.
  
  All plugin callables are expected to adhere to `no-status` and `collection-info`, which are interpretted as
  
  * `no-status` if true means 'no output at all', equivalent to a **quiet** flag
  * `collection-info` if true means 'output extra information' (if need be), equivalent to a **verbose** flag.
  
  ## Disabling a plugin
  
  When it's necessary to disable a plugin, this can be done by:
  
  * Removing the plugin name from the `plugins-required` key of the Mode's config file;
  * Renaming / removing the `config.raku` file name inside the plugin directory
  * Renaming / removing the milestone key inside the plugin's `config.raku` file.
  
  ## Plugin types
  
  The plugin types are as follows.
  
  ### Setup
  
  Config hash must contain **setup** which is the name of a Raku program (a callable) that evaluates to a sub that takes a list of five items, eg.,
  
  ```
  sub ( $source-cache, $mode-cache, Bool $full-render, $source-root, $mode-root, %plugin-options, %options ) { ... }
  
  ```
  
  * **$source-cache**
  
  A `Pod::From::Cache+PostCache` object containing the pod of the sources files New files can be added to the cache object inside the sub using the `.add` method, see [Sources](Sources.md).
  
  * **$mode-cache**
  
  Like the above for the mode content files
  
  * **$full-render**
  
  If True, then the sub should process the cache objects with the .sources method on the cache objects, otherwise with the .list-files method on the cache objects (the .list-files method only provides the files that have changed).
  
  * **$source-root**
  
  This path must be prepended to any sources added (see below) to the cache, otherwise they will not be added to the destination file.
  
  * **$mode-root**
  
  Likewise for the mode sources.
  
  * **%plugin-options**
  
  Has the values of plugin options that over-ride a plugin's own defaults. See [Plugin level configuration](Plugin level configuration.md) for more information.
  
  * **%options**
  
  Has the values of 'collection-info' and 'no-status' flags.
  
  ### Render
  
  The Collection plugin-manager calls the `ProcessedPod.add-plugin` method with the config keys and the path modified to the plugin's subdirectory. The ProcessPod instance is only modified by `Render` plugins, so if there is plugin configuration data that is needed