text: /**
   * Less - Leaner CSS v3.11.0
   * http://lesscss.org
   * 
   * Copyright (c) 2009-2020, Alexis Sellier <self@cloudhead.net>
   * Licensed under the Apache-2.0 License.
   *
   * @license Apache-2.0
   */
  
  (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) {
                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.isPathWithExtension = function (path, ext) {
            var extPos = path.lastIndexOf(ext);
            return extPos !== -1 && extPos === path.length - ext.length;
        };
        AbstractFileManager.prototype.tryAppendExtension = function (path, ext) {
            if (this.isPathWithExtension(path, ext)) {
                return path;
            }
            return 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.$char('-');
                    }
                    var o = this.sub() || entities.dimension() ||
                        entities.color() || entities.variable() ||
                        entities.property() || entities.call() ||
                        entities.quoted(true) || entities.colorKeyword() ||
                        entities.mixinLookup();
                    if (negate) {
                        o.parensInOp = true;
                        o = new (tree.Negative)(o);
                    }
                    return o;
                },
                //
                // Expressions either represent mathematical operations,
                // or white-space delimited Entities.
                //
                //     1px solid black
                //     @var * 2
                //
                expression: function () {
                    var entities = [];
                    var e;
                    var delim;
                    var index = parserInput.i;
                    do {
                        e = this.comment();
                        if (e) {
                            entities.push(e);
                            continue;
                        }
                        e = this.addition() || this.entity();
                        if (e) {
                            entities.push(e);
                            // operations do not allow keyword "/" dimension (e.g. small/20px) so we support that here
                            if (!parserInput.peek(/^\/[\/*]/)) {
                                delim = parserInput.$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
                this.files = {}; // Holds the imported parse trees.
            }
            /**
             * 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 {
                        // Inline imports aren't cached here.
                        // If we start to cache them, please make sure they won't conflict with non-inline imports of the
                        // same name as they used to do before this comment and the condition below have been added.
                        if (!importManager.files[fullPath] && !importOptions.inline) {
                            importManager.files[fullPath] = { root: root, options: importOptions };
                        }
                        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 {
                        // import (multiple) parse trees apparently get altered and can't be cached.
                        // TODO: investigate why this is
                        if (importManager.files[resolvedFilename]
                            && !importManager.files[resolvedFilename].options.multiple
                            && !importOptions.multiple) {
                            fileParsedFunc(null, importManager.files[resolvedFilename].root, 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, 0],
            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.getPossibleFileExtensions = function (path, ext) {
            if (this.isPathWithExtension(path, ext)) {
                return [''];
            }
            // if file doesn't have dot in name it require extention
            if (path.indexOf(".") === -1) {
                return [ext];
            }
            // path has dots in name it might be with or without extention (like .css)
            return [ext, ''];
        };
        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.tryToLoad = function (href) {
            var _this = 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 });
                    }
                }
                _this.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 });
                });
            });
        };
        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?
            var _this = this;
            if (currentDirectory && !this.isPathAbsolute(filename)) {
                filename = currentDirectory + filename;
            }
            var extensions = this.getPossibleFileExtensions(filename, options.ext || '');
            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 hrefs = extensions.map(function (ext) { return _this.tryAppendExtension(href, ext); });
            return hrefs.reduce(function (prev, href) { return prev.catch(function () { return _this.tryToLoad(href); }); }, this.tryToLoad(hrefs.shift()));
        };
        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;
  
  })));
  