function () {
                    var name, index = parserInput.i;

                    if (parserInput.currentChar() === '$' && (name = parserInput.$re(/^\$[\w-]+/))) {
                        return new(tree.Property)(name, index, fileInfo);
                    }
                }
function () {
                    var name, index = parserInput.i;

                    if (parserInput.currentChar() === '$' && (name = parserInput.$re(/^\$[\w-]+/))) {
                        return new(tree.Property)(name, index, fileInfo);
                    }
                }
function ( ) { var name , index = parserInput . i ; if ( parserInput . currentChar ( ) === '$' && ( name = parserInput . $re ( / ^\$[\w-]+ / ) ) ) { return new ( tree . Property ) ( name , index , fileInfo ) ; } }
A Property accessor, such as `$color`, in  background-color: $color
A Property accessor such as $color in background - color : $color