var commonjsGlobal = typeof globalThis !== 'undefined' ? globalThis : typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : {};

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

var estraverse = createCommonjsModule(function (module, exports) {
/*
  Copyright (C) 2012-2013 Yusuke Suzuki <utatane.tea@gmail.com>
  Copyright (C) 2012 Ariya Hidayat <ariya.hidayat@gmail.com>

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*jslint vars:false, bitwise:true*/
/*jshint indent:4*/
/*global exports:true*/
(function clone(exports) {

    var Syntax,
        VisitorOption,
        VisitorKeys,
        BREAK,
        SKIP,
        REMOVE;

    function deepCopy(obj) {
        var ret = {}, key, val;
        for (key in obj) {
            if (obj.hasOwnProperty(key)) {
                val = obj[key];
                if (typeof val === 'object' && val !== null) {
                    ret[key] = deepCopy(val);
                } else {
                    ret[key] = val;
                }
            }
        }
        return ret;
    }

    // based on LLVM libc++ upper_bound / lower_bound
    // MIT License

    function upperBound(array, func) {
        var diff, len, i, current;

        len = array.length;
        i = 0;

        while (len) {
            diff = len >>> 1;
            current = i + diff;
            if (func(array[current])) {
                len = diff;
            } else {
                i = current + 1;
                len -= diff + 1;
            }
        }
        return i;
    }

    Syntax = {
        AssignmentExpression: 'AssignmentExpression',
        AssignmentPattern: 'AssignmentPattern',
        ArrayExpression: 'ArrayExpression',
        ArrayPattern: 'ArrayPattern',
        ArrowFunctionExpression: 'ArrowFunctionExpression',
        AwaitExpression: 'AwaitExpression', // CAUTION: It's deferred to ES7.
        BlockStatement: 'BlockStatement',
        BinaryExpression: 'BinaryExpression',
        BreakStatement: 'BreakStatement',
        CallExpression: 'CallExpression',
        CatchClause: 'CatchClause',
        ClassBody: 'ClassBody',
        ClassDeclaration: 'ClassDeclaration',
        ClassExpression: 'ClassExpression',
        ComprehensionBlock: 'ComprehensionBlock',  // CAUTION: It's deferred to ES7.
        ComprehensionExpression: 'ComprehensionExpression',  // CAUTION: It's deferred to ES7.
        ConditionalExpression: 'ConditionalExpression',
        ContinueStatement: 'ContinueStatement',
        DebuggerStatement: 'DebuggerStatement',
        DirectiveStatement: 'DirectiveStatement',
        DoWhileStatement: 'DoWhileStatement',
        EmptyStatement: 'EmptyStatement',
        ExportAllDeclaration: 'ExportAllDeclaration',
        ExportDefaultDeclaration: 'ExportDefaultDeclaration',
        ExportNamedDeclaration: 'ExportNamedDeclaration',
        ExportSpecifier: 'ExportSpecifier',
        ExpressionStatement: 'ExpressionStatement',
        ForStatement: 'ForStatement',
        ForInStatement: 'ForInStatement',
        ForOfStatement: 'ForOfStatement',
        FunctionDeclaration: 'FunctionDeclaration',
        FunctionExpression: 'FunctionExpression',
        GeneratorExpression: 'GeneratorExpression',  // CAUTION: It's deferred to ES7.
        Identifier: 'Identifier',
        IfStatement: 'IfStatement',
        ImportExpression: 'ImportExpression',
        ImportDeclaration: 'ImportDeclaration',
        ImportDefaultSpecifier: 'ImportDefaultSpecifier',
        ImportNamespaceSpecifier: 'ImportNamespaceSpecifier',
        ImportSpecifier: 'ImportSpecifier',
        Literal: 'Literal',
        LabeledStatement: 'LabeledStatement',
        LogicalExpression: 'LogicalExpression',
        MemberExpression: 'MemberExpression',
        MetaProperty: 'MetaProperty',
        MethodDefinition: 'MethodDefinition',
        ModuleSpecifier: 'ModuleSpecifier',
        NewExpression: 'NewExpression',
        ObjectExpression: 'ObjectExpression',
        ObjectPattern: 'ObjectPattern',
        Program: 'Program',
        Property: 'Property',
        RestElement: 'RestElement',
        ReturnStatement: 'ReturnStatement',
        SequenceExpression: 'SequenceExpression',
        SpreadElement: 'SpreadElement',
        Super: 'Super',
        SwitchStatement: 'SwitchStatement',
        SwitchCase: 'SwitchCase',
        TaggedTemplateExpression: 'TaggedTemplateExpression',
        TemplateElement: 'TemplateElement',
        TemplateLiteral: 'TemplateLiteral',
        ThisExpression: 'ThisExpression',
        ThrowStatement: 'ThrowStatement',
        TryStatement: 'TryStatement',
        UnaryExpression: 'UnaryExpression',
        UpdateExpression: 'UpdateExpression',
        VariableDeclaration: 'VariableDeclaration',
        VariableDeclarator: 'VariableDeclarator',
        WhileStatement: 'WhileStatement',
        WithStatement: 'WithStatement',
        YieldExpression: 'YieldExpression'
    };

    VisitorKeys = {
        AssignmentExpression: ['left', 'right'],
        AssignmentPattern: ['left', 'right'],
        ArrayExpression: ['elements'],
        ArrayPattern: ['elements'],
        ArrowFunctionExpression: ['params', 'body'],
        AwaitExpression: ['argument'], // CAUTION: It's deferred to ES7.
        BlockStatement: ['body'],
        BinaryExpression: ['left', 'right'],
        BreakStatement: ['label'],
        CallExpression: ['callee', 'arguments'],
        CatchClause: ['param', 'body'],
        ClassBody: ['body'],
        ClassDeclaration: ['id', 'superClass', 'body'],
        ClassExpression: ['id', 'superClass', 'body'],
        ComprehensionBlock: ['left', 'right'],  // CAUTION: It's deferred to ES7.
        ComprehensionExpression: ['blocks', 'filter', 'body'],  // CAUTION: It's deferred to ES7.
        ConditionalExpression: ['test', 'consequent', 'alternate'],
        ContinueStatement: ['label'],
        DebuggerStatement: [],
        DirectiveStatement: [],
        DoWhileStatement: ['body', 'test'],
        EmptyStatement: [],
        ExportAllDeclaration: ['source'],
        ExportDefaultDeclaration: ['declaration'],
        ExportNamedDeclaration: ['declaration', 'specifiers', 'source'],
        ExportSpecifier: ['exported', 'local'],
        ExpressionStatement: ['expression'],
        ForStatement: ['init', 'test', 'update', 'body'],
        ForInStatement: ['left', 'right', 'body'],
        ForOfStatement: ['left', 'right', 'body'],
        FunctionDeclaration: ['id', 'params', 'body'],
        FunctionExpression: ['id', 'params', 'body'],
        GeneratorExpression: ['blocks', 'filter', 'body'],  // CAUTION: It's deferred to ES7.
        Identifier: [],
        IfStatement: ['test', 'consequent', 'alternate'],
        ImportExpression: ['source'],
        ImportDeclaration: ['specifiers', 'source'],
        ImportDefaultSpecifier: ['local'],
        ImportNamespaceSpecifier: ['local'],
        ImportSpecifier: ['imported', 'local'],
        Literal: [],
        LabeledStatement: ['label', 'body'],
        LogicalExpression: ['left', 'right'],
        MemberExpression: ['object', 'property'],
        MetaProperty: ['meta', 'property'],
        MethodDefinition: ['key', 'value'],
        ModuleSpecifier: [],
        NewExpression: ['callee', 'arguments'],
        ObjectExpression: ['properties'],
        ObjectPattern: ['properties'],
        Program: ['body'],
        Property: ['key', 'value'],
        RestElement: [ 'argument' ],
        ReturnStatement: ['argument'],
        SequenceExpression: ['expressions'],
        SpreadElement: ['argument'],
        Super: [],
        SwitchStatement: ['discriminant', 'cases'],
        SwitchCase: ['test', 'consequent'],
        TaggedTemplateExpression: ['tag', 'quasi'],
        TemplateElement: [],
        TemplateLiteral: ['quasis', 'expressions'],
        ThisExpression: [],
        ThrowStatement: ['argument'],
        TryStatement: ['block', 'handler', 'finalizer'],
        UnaryExpression: ['argument'],
        UpdateExpression: ['argument'],
        VariableDeclaration: ['declarations'],
        VariableDeclarator: ['id', 'init'],
        WhileStatement: ['test', 'body'],
        WithStatement: ['object', 'body'],
        YieldExpression: ['argument']
    };

    // unique id
    BREAK = {};
    SKIP = {};
    REMOVE = {};

    VisitorOption = {
        Break: BREAK,
        Skip: SKIP,
        Remove: REMOVE
    };

    function Reference(parent, key) {
        this.parent = parent;
        this.key = key;
    }

    Reference.prototype.replace = function replace(node) {
        this.parent[this.key] = node;
    };

    Reference.prototype.remove = function remove() {
        if (Array.isArray(this.parent)) {
            this.parent.splice(this.key, 1);
            return true;
        } else {
            this.replace(null);
            return false;
        }
    };

    function Element(node, path, wrap, ref) {
        this.node = node;
        this.path = path;
        this.wrap = wrap;
        this.ref = ref;
    }

    function Controller() { }

    // API:
    // return property path array from root to current node
    Controller.prototype.path = function path() {
        var i, iz, j, jz, result, element;

        function addToPath(result, path) {
            if (Array.isArray(path)) {
                for (j = 0, jz = path.length; j < jz; ++j) {
                    result.push(path[j]);
                }
            } else {
                result.push(path);
            }
        }

        // root node
        if (!this.__current.path) {
            return null;
        }

        // first node is sentinel, second node is root element
        result = [];
        for (i = 2, iz = this.__leavelist.length; i < iz; ++i) {
            element = this.__leavelist[i];
            addToPath(result, element.path);
        }
        addToPath(result, this.__current.path);
        return result;
    };

    // API:
    // return type of current node
    Controller.prototype.type = function () {
        var node = this.current();
        return node.type || this.__current.wrap;
    };

    // API:
    // return array of parent elements
    Controller.prototype.parents = function parents() {
        var i, iz, result;

        // first node is sentinel
        result = [];
        for (i = 1, iz = this.__leavelist.length; i < iz; ++i) {
            result.push(this.__leavelist[i].node);
        }

        return result;
    };

    // API:
    // return current node
    Controller.prototype.current = function current() {
        return this.__current.node;
    };

    Controller.prototype.__execute = function __execute(callback, element) {
        var previous, result;

        result = undefined;

        previous  = this.__current;
        this.__current = element;
        this.__state = null;
        if (callback) {
            result = callback.call(this, element.node, this.__leavelist[this.__leavelist.length - 1].node);
        }
        this.__current = previous;

        return result;
    };

    // API:
    // notify control skip / break
    Controller.prototype.notify = function notify(flag) {
        this.__state = flag;
    };

    // API:
    // skip child nodes of current node
    Controller.prototype.skip = function () {
        this.notify(SKIP);
    };

    // API:
    // break traversals
    Controller.prototype['break'] = function () {
        this.notify(BREAK);
    };

    // API:
    // remove node
    Controller.prototype.remove = function () {
        this.notify(REMOVE);
    };

    Controller.prototype.__initialize = function(root, visitor) {
        this.visitor = visitor;
        this.root = root;
        this.__worklist = [];
        this.__leavelist = [];
        this.__current = null;
        this.__state = null;
        this.__fallback = null;
        if (visitor.fallback === 'iteration') {
            this.__fallback = Object.keys;
        } else if (typeof visitor.fallback === 'function') {
            this.__fallback = visitor.fallback;
        }

        this.__keys = VisitorKeys;
        if (visitor.keys) {
            this.__keys = Object.assign(Object.create(this.__keys), visitor.keys);
        }
    };

    function isNode(node) {
        if (node == null) {
            return false;
        }
        return typeof node === 'object' && typeof node.type === 'string';
    }

    function isProperty(nodeType, key) {
        return (nodeType === Syntax.ObjectExpression || nodeType === Syntax.ObjectPattern) && 'properties' === key;
    }

    Controller.prototype.traverse = function traverse(root, visitor) {
        var worklist,
            leavelist,
            element,
            node,
            nodeType,
            ret,
            key,
            current,
            current2,
            candidates,
            candidate,
            sentinel;

        this.__initialize(root, visitor);

        sentinel = {};

        // reference
        worklist = this.__worklist;
        leavelist = this.__leavelist;

        // initialize
        worklist.push(new Element(root, null, null, null));
        leavelist.push(new Element(null, null, null, null));

        while (worklist.length) {
            element = worklist.pop();

            if (element === sentinel) {
                element = leavelist.pop();

                ret = this.__execute(visitor.leave, element);

                if (this.__state === BREAK || ret === BREAK) {
                    return;
                }
                continue;
            }

            if (element.node) {

                ret = this.__execute(visitor.enter, element);

                if (this.__state === BREAK || ret === BREAK) {
                    return;
                }

                worklist.push(sentinel);
                leavelist.push(element);

                if (this.__state === SKIP || ret === SKIP) {
                    continue;
                }

                node = element.node;
                nodeType = node.type || element.wrap;
                candidates = this.__keys[nodeType];
                if (!candidates) {
                    if (this.__fallback) {
                        candidates = this.__fallback(node);
                    } else {
                        throw new Error('Unknown node type ' + nodeType + '.');
                    }
                }

                current = candidates.length;
                while ((current -= 1) >= 0) {
                    key = candidates[current];
                    candidate = node[key];
                    if (!candidate) {
                        continue;
                    }

                    if (Array.isArray(candidate)) {
                        current2 = candidate.length;
                        while ((current2 -= 1) >= 0) {
                            if (!candidate[current2]) {
                                continue;
                            }
                            if (isProperty(nodeType, candidates[current])) {
                                element = new Element(candidate[current2], [key, current2], 'Property', null);
                            } else if (isNode(candidate[current2])) {
                                element = new Element(candidate[current2], [key, current2], null, null);
                            } else {
                                continue;
                            }
                            worklist.push(element);
                        }
                    } else if (isNode(candidate)) {
                        worklist.push(new Element(candidate, key, null, null));
                    }
                }
            }
        }
    };

    Controller.prototype.replace = function replace(root, visitor) {
        var worklist,
            leavelist,
            node,
            nodeType,
            target,
            element,
            current,
            current2,
            candidates,
            candidate,
            sentinel,
            outer,
            key;

        function removeElem(element) {
            var i,
                key,
                nextElem,
                parent;

            if (element.ref.remove()) {
                // When the reference is an element of an array.
                key = element.ref.key;
                parent = element.ref.parent;

                // If removed from array, then decrease following items' keys.
                i = worklist.length;
                while (i--) {
                    nextElem = worklist[i];
                    if (nextElem.ref && nextElem.ref.parent === parent) {
                        if  (nextElem.ref.key < key) {
                            break;
                        }
                        --nextElem.ref.key;
                    }
                }
            }
        }

        this.__initialize(root, visitor);

        sentinel = {};

        // reference
        worklist = this.__worklist;
        leavelist = this.__leavelist;

        // initialize
        outer = {
            root: root
        };
        element = new Element(root, null, null, new Reference(outer, 'root'));
        worklist.push(element);
        leavelist.push(element);

        while (worklist.length) {
            element = worklist.pop();

            if (element === sentinel) {
                element = leavelist.pop();

                target = this.__execute(visitor.leave, element);

                // node may be replaced with null,
                // so distinguish between undefined and null in this place
                if (target !== undefined && target !== BREAK && target !== SKIP && target !== REMOVE) {
                    // replace
                    element.ref.replace(target);
                }

                if (this.__state === REMOVE || target === REMOVE) {
                    removeElem(element);
                }

                if (this.__state === BREAK || target === BREAK) {
                    return outer.root;
                }
                continue;
            }

            target = this.__execute(visitor.enter, element);

            // node may be replaced with null,
            // so distinguish between undefined and null in this place
            if (target !== undefined && target !== BREAK && target !== SKIP && target !== REMOVE) {
                // replace
                element.ref.replace(target);
                element.node = target;
            }

            if (this.__state === REMOVE || target === REMOVE) {
                removeElem(element);
                element.node = null;
            }

            if (this.__state === BREAK || target === BREAK) {
                return outer.root;
            }

            // node may be null
            node = element.node;
            if (!node) {
                continue;
            }

            worklist.push(sentinel);
            leavelist.push(element);

            if (this.__state === SKIP || target === SKIP) {
                continue;
            }

            nodeType = node.type || element.wrap;
            candidates = this.__keys[nodeType];
            if (!candidates) {
                if (this.__fallback) {
                    candidates = this.__fallback(node);
                } else {
                    throw new Error('Unknown node type ' + nodeType + '.');
                }
            }

            current = candidates.length;
            while ((current -= 1) >= 0) {
                key = candidates[current];
                candidate = node[key];
                if (!candidate) {
                    continue;
                }

                if (Array.isArray(candidate)) {
                    current2 = candidate.length;
                    while ((current2 -= 1) >= 0) {
                        if (!candidate[current2]) {
                            continue;
                        }
                        if (isProperty(nodeType, candidates[current])) {
                            element = new Element(candidate[current2], [key, current2], 'Property', new Reference(candidate, current2));
                        } else if (isNode(candidate[current2])) {
                            element = new Element(candidate[current2], [key, current2], null, new Reference(candidate, current2));
                        } else {
                            continue;
                        }
                        worklist.push(element);
                    }
                } else if (isNode(candidate)) {
                    worklist.push(new Element(candidate, key, null, new Reference(node, key)));
                }
            }
        }

        return outer.root;
    };

    function traverse(root, visitor) {
        var controller = new Controller();
        return controller.traverse(root, visitor);
    }

    function replace(root, visitor) {
        var controller = new Controller();
        return controller.replace(root, visitor);
    }

    function extendCommentRange(comment, tokens) {
        var target;

        target = upperBound(tokens, function search(token) {
            return token.range[0] > comment.range[0];
        });

        comment.extendedRange = [comment.range[0], comment.range[1]];

        if (target !== tokens.length) {
            comment.extendedRange[1] = tokens[target].range[0];
        }

        target -= 1;
        if (target >= 0) {
            comment.extendedRange[0] = tokens[target].range[1];
        }

        return comment;
    }

    function attachComments(tree, providedComments, tokens) {
        // At first, we should calculate extended comment ranges.
        var comments = [], comment, len, i, cursor;

        if (!tree.range) {
            throw new Error('attachComments needs range information');
        }

        // tokens array is empty, we attach comments to tree as 'leadingComments'
        if (!tokens.length) {
            if (providedComments.length) {
                for (i = 0, len = providedComments.length; i < len; i += 1) {
                    comment = deepCopy(providedComments[i]);
                    comment.extendedRange = [0, tree.range[0]];
                    comments.push(comment);
                }
                tree.leadingComments = comments;
            }
            return tree;
        }

        for (i = 0, len = providedComments.length; i < len; i += 1) {
            comments.push(extendCommentRange(deepCopy(providedComments[i]), tokens));
        }

        // This is based on John Freeman's implementation.
        cursor = 0;
        traverse(tree, {
            enter: function (node) {
                var comment;

                while (cursor < comments.length) {
                    comment = comments[cursor];
                    if (comment.extendedRange[1] > node.range[0]) {
                        break;
                    }

                    if (comment.extendedRange[1] === node.range[0]) {
                        if (!node.leadingComments) {
                            node.leadingComments = [];
                        }
                        node.leadingComments.push(comment);
                        comments.splice(cursor, 1);
                    } else {
                        cursor += 1;
                    }
                }

                // already out of owned node
                if (cursor === comments.length) {
                    return VisitorOption.Break;
                }

                if (comments[cursor].extendedRange[0] > node.range[1]) {
                    return VisitorOption.Skip;
                }
            }
        });

        cursor = 0;
        traverse(tree, {
            leave: function (node) {
                var comment;

                while (cursor < comments.length) {
                    comment = comments[cursor];
                    if (node.range[1] < comment.extendedRange[0]) {
                        break;
                    }

                    if (node.range[1] === comment.extendedRange[0]) {
                        if (!node.trailingComments) {
                            node.trailingComments = [];
                        }
                        node.trailingComments.push(comment);
                        comments.splice(cursor, 1);
                    } else {
                        cursor += 1;
                    }
                }

                // already out of owned node
                if (cursor === comments.length) {
                    return VisitorOption.Break;
                }

                if (comments[cursor].extendedRange[0] > node.range[1]) {
                    return VisitorOption.Skip;
                }
            }
        });

        return tree;
    }

    exports.Syntax = Syntax;
    exports.traverse = traverse;
    exports.replace = replace;
    exports.attachComments = attachComments;
    exports.VisitorKeys = VisitorKeys;
    exports.VisitorOption = VisitorOption;
    exports.Controller = Controller;
    exports.cloneEnvironment = function () { return clone({}); };

    return exports;
}(exports));
/* vim: set sw=4 ts=4 et tw=80 : */
});

var parser = createCommonjsModule(function (module) {
/*
 * Generated by PEG.js 0.10.0.
 *
 * http://pegjs.org/
 */
(function(root, factory) {
  if ( module.exports) {
    module.exports = factory();
  }
})(commonjsGlobal, function() {

  function peg$subclass(child, parent) {
    function ctor() { this.constructor = child; }
    ctor.prototype = parent.prototype;
    child.prototype = new ctor();
  }

  function peg$SyntaxError(message, expected, found, location) {
    this.message  = message;
    this.expected = expected;
    this.found    = found;
    this.location = location;
    this.name     = "SyntaxError";

    if (typeof Error.captureStackTrace === "function") {
      Error.captureStackTrace(this, peg$SyntaxError);
    }
  }

  peg$subclass(peg$SyntaxError, Error);

  peg$SyntaxError.buildMessage = function(expected, found) {
    var DESCRIBE_EXPECTATION_FNS = {
          literal: function(expectation) {
            return "\"" + literalEscape(expectation.text) + "\"";
          },

          "class": function(expectation) {
            var escapedParts = "",
                i;

            for (i = 0; i < expectation.parts.length; i++) {
              escapedParts += expectation.parts[i] instanceof Array
                ? classEscape(expectation.parts[i][0]) + "-" + classEscape(expectation.parts[i][1])
                : classEscape(expectation.parts[i]);
            }

            return "[" + (expectation.inverted ? "^" : "") + escapedParts + "]";
          },

          any: function(expectation) {
            return "any character";
          },

          end: function(expectation) {
            return "end of input";
          },

          other: function(expectation) {
            return expectation.description;
          }
        };

    function hex(ch) {
      return ch.charCodeAt(0).toString(16).toUpperCase();
    }

    function literalEscape(s) {
      return s
        .replace(/\\/g, '\\\\')
        .replace(/"/g,  '\\"')
        .replace(/\0/g, '\\0')
        .replace(/\t/g, '\\t')
        .replace(/\n/g, '\\n')
        .replace(/\r/g, '\\r')
        .replace(/[\x00-\x0F]/g,          function(ch) { return '\\x0' + hex(ch); })
        .replace(/[\x10-\x1F\x7F-\x9F]/g, function(ch) { return '\\x'  + hex(ch); });
    }

    function classEscape(s) {
      return s
        .replace(/\\/g, '\\\\')
        .replace(/\]/g, '\\]')
        .replace(/\^/g, '\\^')
        .replace(/-/g,  '\\-')
        .replace(/\0/g, '\\0')
        .replace(/\t/g, '\\t')
        .replace(/\n/g, '\\n')
        .replace(/\r/g, '\\r')
        .replace(/[\x00-\x0F]/g,          function(ch) { return '\\x0' + hex(ch); })
        .replace(/[\x10-\x1F\x7F-\x9F]/g, function(ch) { return '\\x'  + hex(ch); });
    }

    function describeExpectation(expectation) {
      return DESCRIBE_EXPECTATION_FNS[expectation.type](expectation);
    }

    function describeExpected(expected) {
      var descriptions = new Array(expected.length),
          i, j;

      for (i = 0; i < expected.length; i++) {
        descriptions[i] = describeExpectation(expected[i]);
      }

      descriptions.sort();

      if (descriptions.length > 0) {
        for (i = 1, j = 1; i < descriptions.length; i++) {
          if (descriptions[i - 1] !== descriptions[i]) {
            descriptions[j] = descriptions[i];
            j++;
          }
        }
        descriptions.length = j;
      }

      switch (descriptions.length) {
        case 1:
          return descriptions[0];

        case 2:
          return descriptions[0] + " or " + descriptions[1];

        default:
          return descriptions.slice(0, -1).join(", ")
            + ", or "
            + descriptions[descriptions.length - 1];
      }
    }

    function describeFound(found) {
      return found ? "\"" + literalEscape(found) + "\"" : "end of input";
    }

    return "Expected " + describeExpected(expected) + " but " + describeFound(found) + " found.";
  };

  function peg$parse(input, options) {
    options = options !== void 0 ? options : {};

    var peg$FAILED = {},

        peg$startRuleFunctions = { start: peg$parsestart },
        peg$startRuleFunction  = peg$parsestart,

        peg$c0 = function(ss) {
            return ss.length === 1 ? ss[0] : { type: 'matches', selectors: ss };
          },
        peg$c1 = function() { return void 0; },
        peg$c2 = " ",
        peg$c3 = peg$literalExpectation(" ", false),
        peg$c4 = /^[^ [\],():#!=><~+.]/,
        peg$c5 = peg$classExpectation([" ", "[", "]", ",", "(", ")", ":", "#", "!", "=", ">", "<", "~", "+", "."], true, false),
        peg$c6 = function(i) { return i.join(''); },
        peg$c7 = ">",
        peg$c8 = peg$literalExpectation(">", false),
        peg$c9 = function() { return 'child'; },
        peg$c10 = "~",
        peg$c11 = peg$literalExpectation("~", false),
        peg$c12 = function() { return 'sibling'; },
        peg$c13 = "+",
        peg$c14 = peg$literalExpectation("+", false),
        peg$c15 = function() { return 'adjacent'; },
        peg$c16 = function() { return 'descendant'; },
        peg$c17 = ",",
        peg$c18 = peg$literalExpectation(",", false),
        peg$c19 = function(s, ss) {
          return [s].concat(ss.map(function (s) { return s[3]; }));
        },
        peg$c20 = function(a, ops) {
            return ops.reduce(function (memo, rhs) {
              return { type: rhs[0], left: memo, right: rhs[1] };
            }, a);
          },
        peg$c21 = "!",
        peg$c22 = peg$literalExpectation("!", false),
        peg$c23 = function(subject, as) {
            const b = as.length === 1 ? as[0] : { type: 'compound', selectors: as };
            if(subject) b.subject = true;
            return b;
          },
        peg$c24 = "*",
        peg$c25 = peg$literalExpectation("*", false),
        peg$c26 = function(a) { return { type: 'wildcard', value: a }; },
        peg$c27 = "#",
        peg$c28 = peg$literalExpectation("#", false),
        peg$c29 = function(i) { return { type: 'identifier', value: i }; },
        peg$c30 = "[",
        peg$c31 = peg$literalExpectation("[", false),
        peg$c32 = "]",
        peg$c33 = peg$literalExpectation("]", false),
        peg$c34 = function(v) { return v; },
        peg$c35 = /^[><!]/,
        peg$c36 = peg$classExpectation([">", "<", "!"], false, false),
        peg$c37 = "=",
        peg$c38 = peg$literalExpectation("=", false),
        peg$c39 = function(a) { return (a || '') + '='; },
        peg$c40 = /^[><]/,
        peg$c41 = peg$classExpectation([">", "<"], false, false),
        peg$c42 = ".",
        peg$c43 = peg$literalExpectation(".", false),
        peg$c44 = function(name, op, value) {
              return { type: 'attribute', name: name, operator: op, value: value };
            },
        peg$c45 = function(name) { return { type: 'attribute', name: name }; },
        peg$c46 = "\"",
        peg$c47 = peg$literalExpectation("\"", false),
        peg$c48 = /^[^\\"]/,
        peg$c49 = peg$classExpectation(["\\", "\""], true, false),
        peg$c50 = "\\",
        peg$c51 = peg$literalExpectation("\\", false),
        peg$c52 = peg$anyExpectation(),
        peg$c53 = function(a, b) { return a + b; },
        peg$c54 = function(d) {
                return { type: 'literal', value: strUnescape(d.join('')) };
              },
        peg$c55 = "'",
        peg$c56 = peg$literalExpectation("'", false),
        peg$c57 = /^[^\\']/,
        peg$c58 = peg$classExpectation(["\\", "'"], true, false),
        peg$c59 = /^[0-9]/,
        peg$c60 = peg$classExpectation([["0", "9"]], false, false),
        peg$c61 = function(a, b) {
                // Can use `a.flat().join('')` once supported
                const leadingDecimals = a ? [].concat.apply([], a).join('') : '';
                return { type: 'literal', value: parseFloat(leadingDecimals + b.join('')) };
              },
        peg$c62 = function(i) { return { type: 'literal', value: i }; },
        peg$c63 = "type(",
        peg$c64 = peg$literalExpectation("type(", false),
        peg$c65 = /^[^ )]/,
        peg$c66 = peg$classExpectation([" ", ")"], true, false),
        peg$c67 = ")",
        peg$c68 = peg$literalExpectation(")", false),
        peg$c69 = function(t) { return { type: 'type', value: t.join('') }; },
        peg$c70 = /^[imsu]/,
        peg$c71 = peg$classExpectation(["i", "m", "s", "u"], false, false),
        peg$c72 = "/",
        peg$c73 = peg$literalExpectation("/", false),
        peg$c74 = /^[^\/]/,
        peg$c75 = peg$classExpectation(["/"], true, false),
        peg$c76 = function(d, flgs) { return {
              type: 'regexp', value: new RegExp(d.join(''), flgs ? flgs.join('') : '') };
            },
        peg$c77 = function(i, is) {
          return { type: 'field', name: is.reduce(function(memo, p){ return memo + p[0] + p[1]; }, i)};
        },
        peg$c78 = ":not(",
        peg$c79 = peg$literalExpectation(":not(", false),
        peg$c80 = function(ss) { return { type: 'not', selectors: ss }; },
        peg$c81 = ":matches(",
        peg$c82 = peg$literalExpectation(":matches(", false),
        peg$c83 = function(ss) { return { type: 'matches', selectors: ss }; },
        peg$c84 = ":has(",
        peg$c85 = peg$literalExpectation(":has(", false),
        peg$c86 = function(ss) { return { type: 'has', selectors: ss }; },
        peg$c87 = ":first-child",
        peg$c88 = peg$literalExpectation(":first-child", false),
        peg$c89 = function() { return nth(1); },
        peg$c90 = ":last-child",
        peg$c91 = peg$literalExpectation(":last-child", false),
        peg$c92 = function() { return nthLast(1); },
        peg$c93 = ":nth-child(",
        peg$c94 = peg$literalExpectation(":nth-child(", false),
        peg$c95 = function(n) { return nth(parseInt(n.join(''), 10)); },
        peg$c96 = ":nth-last-child(",
        peg$c97 = peg$literalExpectation(":nth-last-child(", false),
        peg$c98 = function(n) { return nthLast(parseInt(n.join(''), 10)); },
        peg$c99 = ":",
        peg$c100 = peg$literalExpectation(":", false),
        peg$c101 = "statement",
        peg$c102 = peg$literalExpectation("statement", true),
        peg$c103 = "expression",
        peg$c104 = peg$literalExpectation("expression", true),
        peg$c105 = "declaration",
        peg$c106 = peg$literalExpectation("declaration", true),
        peg$c107 = "function",
        peg$c108 = peg$literalExpectation("function", true),
        peg$c109 = "pattern",
        peg$c110 = peg$literalExpectation("pattern", true),
        peg$c111 = function(c) {
          return { type: 'class', name: c };
        },

        peg$currPos          = 0,
        peg$posDetailsCache  = [{ line: 1, column: 1 }],
        peg$maxFailPos       = 0,
        peg$maxFailExpected  = [],
        peg$resultsCache = {},

        peg$result;

    if ("startRule" in options) {
      if (!(options.startRule in peg$startRuleFunctions)) {
        throw new Error("Can't start parsing from rule \"" + options.startRule + "\".");
      }

      peg$startRuleFunction = peg$startRuleFunctions[options.startRule];
    }

    function peg$literalExpectation(text, ignoreCase) {
      return { type: "literal", text: text, ignoreCase: ignoreCase };
    }

    function peg$classExpectation(parts, inverted, ignoreCase) {
      return { type: "class", parts: parts, inverted: inverted, ignoreCase: ignoreCase };
    }

    function peg$anyExpectation() {
      return { type: "any" };
    }

    function peg$endExpectation() {
      return { type: "end" };
    }

    function peg$computePosDetails(pos) {
      var details = peg$posDetailsCache[pos], p;

      if (details) {
        return details;
      } else {
        p = pos - 1;
        while (!peg$posDetailsCache[p]) {
          p--;
        }

        details = peg$posDetailsCache[p];
        details = {
          line:   details.line,
          column: details.column
        };

        while (p < pos) {
          if (input.charCodeAt(p) === 10) {
            details.line++;
            details.column = 1;
          } else {
            details.column++;
          }

          p++;
        }

        peg$posDetailsCache[pos] = details;
        return details;
      }
    }

    function peg$computeLocation(startPos, endPos) {
      var startPosDetails = peg$computePosDetails(startPos),
          endPosDetails   = peg$computePosDetails(endPos);

      return {
        start: {
          offset: startPos,
          line:   startPosDetails.line,
          column: startPosDetails.column
        },
        end: {
          offset: endPos,
          line:   endPosDetails.line,
          column: endPosDetails.column
        }
      };
    }

    function peg$fail(expected) {
      if (peg$currPos < peg$maxFailPos) { return; }

      if (peg$currPos > peg$maxFailPos) {
        peg$maxFailPos = peg$currPos;
        peg$maxFailExpected = [];
      }

      peg$maxFailExpected.push(expected);
    }

    function peg$buildStructuredError(expected, found, location) {
      return new peg$SyntaxError(
        peg$SyntaxError.buildMessage(expected, found),
        expected,
        found,
        location
      );
    }

    function peg$parsestart() {
      var s0, s1, s2, s3;

      var key    = peg$currPos * 30 + 0,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = peg$parse_();
      if (s1 !== peg$FAILED) {
        s2 = peg$parseselectors();
        if (s2 !== peg$FAILED) {
          s3 = peg$parse_();
          if (s3 !== peg$FAILED) {
            s1 = peg$c0(s2);
            s0 = s1;
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }
      if (s0 === peg$FAILED) {
        s0 = peg$currPos;
        s1 = peg$parse_();
        if (s1 !== peg$FAILED) {
          s1 = peg$c1();
        }
        s0 = s1;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parse_() {
      var s0, s1;

      var key    = peg$currPos * 30 + 1,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = [];
      if (input.charCodeAt(peg$currPos) === 32) {
        s1 = peg$c2;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c3); }
      }
      while (s1 !== peg$FAILED) {
        s0.push(s1);
        if (input.charCodeAt(peg$currPos) === 32) {
          s1 = peg$c2;
          peg$currPos++;
        } else {
          s1 = peg$FAILED;
          { peg$fail(peg$c3); }
        }
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseidentifierName() {
      var s0, s1, s2;

      var key    = peg$currPos * 30 + 2,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = [];
      if (peg$c4.test(input.charAt(peg$currPos))) {
        s2 = input.charAt(peg$currPos);
        peg$currPos++;
      } else {
        s2 = peg$FAILED;
        { peg$fail(peg$c5); }
      }
      if (s2 !== peg$FAILED) {
        while (s2 !== peg$FAILED) {
          s1.push(s2);
          if (peg$c4.test(input.charAt(peg$currPos))) {
            s2 = input.charAt(peg$currPos);
            peg$currPos++;
          } else {
            s2 = peg$FAILED;
            { peg$fail(peg$c5); }
          }
        }
      } else {
        s1 = peg$FAILED;
      }
      if (s1 !== peg$FAILED) {
        s1 = peg$c6(s1);
      }
      s0 = s1;

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsebinaryOp() {
      var s0, s1, s2, s3;

      var key    = peg$currPos * 30 + 3,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = peg$parse_();
      if (s1 !== peg$FAILED) {
        if (input.charCodeAt(peg$currPos) === 62) {
          s2 = peg$c7;
          peg$currPos++;
        } else {
          s2 = peg$FAILED;
          { peg$fail(peg$c8); }
        }
        if (s2 !== peg$FAILED) {
          s3 = peg$parse_();
          if (s3 !== peg$FAILED) {
            s1 = peg$c9();
            s0 = s1;
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }
      if (s0 === peg$FAILED) {
        s0 = peg$currPos;
        s1 = peg$parse_();
        if (s1 !== peg$FAILED) {
          if (input.charCodeAt(peg$currPos) === 126) {
            s2 = peg$c10;
            peg$currPos++;
          } else {
            s2 = peg$FAILED;
            { peg$fail(peg$c11); }
          }
          if (s2 !== peg$FAILED) {
            s3 = peg$parse_();
            if (s3 !== peg$FAILED) {
              s1 = peg$c12();
              s0 = s1;
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
        if (s0 === peg$FAILED) {
          s0 = peg$currPos;
          s1 = peg$parse_();
          if (s1 !== peg$FAILED) {
            if (input.charCodeAt(peg$currPos) === 43) {
              s2 = peg$c13;
              peg$currPos++;
            } else {
              s2 = peg$FAILED;
              { peg$fail(peg$c14); }
            }
            if (s2 !== peg$FAILED) {
              s3 = peg$parse_();
              if (s3 !== peg$FAILED) {
                s1 = peg$c15();
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
          if (s0 === peg$FAILED) {
            s0 = peg$currPos;
            if (input.charCodeAt(peg$currPos) === 32) {
              s1 = peg$c2;
              peg$currPos++;
            } else {
              s1 = peg$FAILED;
              { peg$fail(peg$c3); }
            }
            if (s1 !== peg$FAILED) {
              s2 = peg$parse_();
              if (s2 !== peg$FAILED) {
                s1 = peg$c16();
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          }
        }
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseselectors() {
      var s0, s1, s2, s3, s4, s5, s6, s7;

      var key    = peg$currPos * 30 + 4,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = peg$parseselector();
      if (s1 !== peg$FAILED) {
        s2 = [];
        s3 = peg$currPos;
        s4 = peg$parse_();
        if (s4 !== peg$FAILED) {
          if (input.charCodeAt(peg$currPos) === 44) {
            s5 = peg$c17;
            peg$currPos++;
          } else {
            s5 = peg$FAILED;
            { peg$fail(peg$c18); }
          }
          if (s5 !== peg$FAILED) {
            s6 = peg$parse_();
            if (s6 !== peg$FAILED) {
              s7 = peg$parseselector();
              if (s7 !== peg$FAILED) {
                s4 = [s4, s5, s6, s7];
                s3 = s4;
              } else {
                peg$currPos = s3;
                s3 = peg$FAILED;
              }
            } else {
              peg$currPos = s3;
              s3 = peg$FAILED;
            }
          } else {
            peg$currPos = s3;
            s3 = peg$FAILED;
          }
        } else {
          peg$currPos = s3;
          s3 = peg$FAILED;
        }
        while (s3 !== peg$FAILED) {
          s2.push(s3);
          s3 = peg$currPos;
          s4 = peg$parse_();
          if (s4 !== peg$FAILED) {
            if (input.charCodeAt(peg$currPos) === 44) {
              s5 = peg$c17;
              peg$currPos++;
            } else {
              s5 = peg$FAILED;
              { peg$fail(peg$c18); }
            }
            if (s5 !== peg$FAILED) {
              s6 = peg$parse_();
              if (s6 !== peg$FAILED) {
                s7 = peg$parseselector();
                if (s7 !== peg$FAILED) {
                  s4 = [s4, s5, s6, s7];
                  s3 = s4;
                } else {
                  peg$currPos = s3;
                  s3 = peg$FAILED;
                }
              } else {
                peg$currPos = s3;
                s3 = peg$FAILED;
              }
            } else {
              peg$currPos = s3;
              s3 = peg$FAILED;
            }
          } else {
            peg$currPos = s3;
            s3 = peg$FAILED;
          }
        }
        if (s2 !== peg$FAILED) {
          s1 = peg$c19(s1, s2);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseselector() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 5,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = peg$parsesequence();
      if (s1 !== peg$FAILED) {
        s2 = [];
        s3 = peg$currPos;
        s4 = peg$parsebinaryOp();
        if (s4 !== peg$FAILED) {
          s5 = peg$parsesequence();
          if (s5 !== peg$FAILED) {
            s4 = [s4, s5];
            s3 = s4;
          } else {
            peg$currPos = s3;
            s3 = peg$FAILED;
          }
        } else {
          peg$currPos = s3;
          s3 = peg$FAILED;
        }
        while (s3 !== peg$FAILED) {
          s2.push(s3);
          s3 = peg$currPos;
          s4 = peg$parsebinaryOp();
          if (s4 !== peg$FAILED) {
            s5 = peg$parsesequence();
            if (s5 !== peg$FAILED) {
              s4 = [s4, s5];
              s3 = s4;
            } else {
              peg$currPos = s3;
              s3 = peg$FAILED;
            }
          } else {
            peg$currPos = s3;
            s3 = peg$FAILED;
          }
        }
        if (s2 !== peg$FAILED) {
          s1 = peg$c20(s1, s2);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsesequence() {
      var s0, s1, s2, s3;

      var key    = peg$currPos * 30 + 6,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 33) {
        s1 = peg$c21;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c22); }
      }
      if (s1 === peg$FAILED) {
        s1 = null;
      }
      if (s1 !== peg$FAILED) {
        s2 = [];
        s3 = peg$parseatom();
        if (s3 !== peg$FAILED) {
          while (s3 !== peg$FAILED) {
            s2.push(s3);
            s3 = peg$parseatom();
          }
        } else {
          s2 = peg$FAILED;
        }
        if (s2 !== peg$FAILED) {
          s1 = peg$c23(s1, s2);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseatom() {
      var s0;

      var key    = peg$currPos * 30 + 7,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$parsewildcard();
      if (s0 === peg$FAILED) {
        s0 = peg$parseidentifier();
        if (s0 === peg$FAILED) {
          s0 = peg$parseattr();
          if (s0 === peg$FAILED) {
            s0 = peg$parsefield();
            if (s0 === peg$FAILED) {
              s0 = peg$parsenegation();
              if (s0 === peg$FAILED) {
                s0 = peg$parsematches();
                if (s0 === peg$FAILED) {
                  s0 = peg$parsehas();
                  if (s0 === peg$FAILED) {
                    s0 = peg$parsefirstChild();
                    if (s0 === peg$FAILED) {
                      s0 = peg$parselastChild();
                      if (s0 === peg$FAILED) {
                        s0 = peg$parsenthChild();
                        if (s0 === peg$FAILED) {
                          s0 = peg$parsenthLastChild();
                          if (s0 === peg$FAILED) {
                            s0 = peg$parseclass();
                          }
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsewildcard() {
      var s0, s1;

      var key    = peg$currPos * 30 + 8,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 42) {
        s1 = peg$c24;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c25); }
      }
      if (s1 !== peg$FAILED) {
        s1 = peg$c26(s1);
      }
      s0 = s1;

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseidentifier() {
      var s0, s1, s2;

      var key    = peg$currPos * 30 + 9,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 35) {
        s1 = peg$c27;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c28); }
      }
      if (s1 === peg$FAILED) {
        s1 = null;
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parseidentifierName();
        if (s2 !== peg$FAILED) {
          s1 = peg$c29(s2);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseattr() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 10,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 91) {
        s1 = peg$c30;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c31); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = peg$parseattrValue();
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              if (input.charCodeAt(peg$currPos) === 93) {
                s5 = peg$c32;
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c33); }
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c34(s3);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseattrOps() {
      var s0, s1, s2;

      var key    = peg$currPos * 30 + 11,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (peg$c35.test(input.charAt(peg$currPos))) {
        s1 = input.charAt(peg$currPos);
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c36); }
      }
      if (s1 === peg$FAILED) {
        s1 = null;
      }
      if (s1 !== peg$FAILED) {
        if (input.charCodeAt(peg$currPos) === 61) {
          s2 = peg$c37;
          peg$currPos++;
        } else {
          s2 = peg$FAILED;
          { peg$fail(peg$c38); }
        }
        if (s2 !== peg$FAILED) {
          s1 = peg$c39(s1);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }
      if (s0 === peg$FAILED) {
        if (peg$c40.test(input.charAt(peg$currPos))) {
          s0 = input.charAt(peg$currPos);
          peg$currPos++;
        } else {
          s0 = peg$FAILED;
          { peg$fail(peg$c41); }
        }
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseattrEqOps() {
      var s0, s1, s2;

      var key    = peg$currPos * 30 + 12,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 33) {
        s1 = peg$c21;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c22); }
      }
      if (s1 === peg$FAILED) {
        s1 = null;
      }
      if (s1 !== peg$FAILED) {
        if (input.charCodeAt(peg$currPos) === 61) {
          s2 = peg$c37;
          peg$currPos++;
        } else {
          s2 = peg$FAILED;
          { peg$fail(peg$c38); }
        }
        if (s2 !== peg$FAILED) {
          s1 = peg$c39(s1);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseattrName() {
      var s0, s1, s2;

      var key    = peg$currPos * 30 + 13,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = [];
      s2 = peg$parseidentifierName();
      if (s2 === peg$FAILED) {
        if (input.charCodeAt(peg$currPos) === 46) {
          s2 = peg$c42;
          peg$currPos++;
        } else {
          s2 = peg$FAILED;
          { peg$fail(peg$c43); }
        }
      }
      if (s2 !== peg$FAILED) {
        while (s2 !== peg$FAILED) {
          s1.push(s2);
          s2 = peg$parseidentifierName();
          if (s2 === peg$FAILED) {
            if (input.charCodeAt(peg$currPos) === 46) {
              s2 = peg$c42;
              peg$currPos++;
            } else {
              s2 = peg$FAILED;
              { peg$fail(peg$c43); }
            }
          }
        }
      } else {
        s1 = peg$FAILED;
      }
      if (s1 !== peg$FAILED) {
        s1 = peg$c6(s1);
      }
      s0 = s1;

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseattrValue() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 14,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = peg$parseattrName();
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = peg$parseattrEqOps();
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              s5 = peg$parsetype();
              if (s5 === peg$FAILED) {
                s5 = peg$parseregex();
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c44(s1, s3, s5);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }
      if (s0 === peg$FAILED) {
        s0 = peg$currPos;
        s1 = peg$parseattrName();
        if (s1 !== peg$FAILED) {
          s2 = peg$parse_();
          if (s2 !== peg$FAILED) {
            s3 = peg$parseattrOps();
            if (s3 !== peg$FAILED) {
              s4 = peg$parse_();
              if (s4 !== peg$FAILED) {
                s5 = peg$parsestring();
                if (s5 === peg$FAILED) {
                  s5 = peg$parsenumber();
                  if (s5 === peg$FAILED) {
                    s5 = peg$parsepath();
                  }
                }
                if (s5 !== peg$FAILED) {
                  s1 = peg$c44(s1, s3, s5);
                  s0 = s1;
                } else {
                  peg$currPos = s0;
                  s0 = peg$FAILED;
                }
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
        if (s0 === peg$FAILED) {
          s0 = peg$currPos;
          s1 = peg$parseattrName();
          if (s1 !== peg$FAILED) {
            s1 = peg$c45(s1);
          }
          s0 = s1;
        }
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsestring() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 15,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 34) {
        s1 = peg$c46;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c47); }
      }
      if (s1 !== peg$FAILED) {
        s2 = [];
        if (peg$c48.test(input.charAt(peg$currPos))) {
          s3 = input.charAt(peg$currPos);
          peg$currPos++;
        } else {
          s3 = peg$FAILED;
          { peg$fail(peg$c49); }
        }
        if (s3 === peg$FAILED) {
          s3 = peg$currPos;
          if (input.charCodeAt(peg$currPos) === 92) {
            s4 = peg$c50;
            peg$currPos++;
          } else {
            s4 = peg$FAILED;
            { peg$fail(peg$c51); }
          }
          if (s4 !== peg$FAILED) {
            if (input.length > peg$currPos) {
              s5 = input.charAt(peg$currPos);
              peg$currPos++;
            } else {
              s5 = peg$FAILED;
              { peg$fail(peg$c52); }
            }
            if (s5 !== peg$FAILED) {
              s4 = peg$c53(s4, s5);
              s3 = s4;
            } else {
              peg$currPos = s3;
              s3 = peg$FAILED;
            }
          } else {
            peg$currPos = s3;
            s3 = peg$FAILED;
          }
        }
        while (s3 !== peg$FAILED) {
          s2.push(s3);
          if (peg$c48.test(input.charAt(peg$currPos))) {
            s3 = input.charAt(peg$currPos);
            peg$currPos++;
          } else {
            s3 = peg$FAILED;
            { peg$fail(peg$c49); }
          }
          if (s3 === peg$FAILED) {
            s3 = peg$currPos;
            if (input.charCodeAt(peg$currPos) === 92) {
              s4 = peg$c50;
              peg$currPos++;
            } else {
              s4 = peg$FAILED;
              { peg$fail(peg$c51); }
            }
            if (s4 !== peg$FAILED) {
              if (input.length > peg$currPos) {
                s5 = input.charAt(peg$currPos);
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c52); }
              }
              if (s5 !== peg$FAILED) {
                s4 = peg$c53(s4, s5);
                s3 = s4;
              } else {
                peg$currPos = s3;
                s3 = peg$FAILED;
              }
            } else {
              peg$currPos = s3;
              s3 = peg$FAILED;
            }
          }
        }
        if (s2 !== peg$FAILED) {
          if (input.charCodeAt(peg$currPos) === 34) {
            s3 = peg$c46;
            peg$currPos++;
          } else {
            s3 = peg$FAILED;
            { peg$fail(peg$c47); }
          }
          if (s3 !== peg$FAILED) {
            s1 = peg$c54(s2);
            s0 = s1;
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }
      if (s0 === peg$FAILED) {
        s0 = peg$currPos;
        if (input.charCodeAt(peg$currPos) === 39) {
          s1 = peg$c55;
          peg$currPos++;
        } else {
          s1 = peg$FAILED;
          { peg$fail(peg$c56); }
        }
        if (s1 !== peg$FAILED) {
          s2 = [];
          if (peg$c57.test(input.charAt(peg$currPos))) {
            s3 = input.charAt(peg$currPos);
            peg$currPos++;
          } else {
            s3 = peg$FAILED;
            { peg$fail(peg$c58); }
          }
          if (s3 === peg$FAILED) {
            s3 = peg$currPos;
            if (input.charCodeAt(peg$currPos) === 92) {
              s4 = peg$c50;
              peg$currPos++;
            } else {
              s4 = peg$FAILED;
              { peg$fail(peg$c51); }
            }
            if (s4 !== peg$FAILED) {
              if (input.length > peg$currPos) {
                s5 = input.charAt(peg$currPos);
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c52); }
              }
              if (s5 !== peg$FAILED) {
                s4 = peg$c53(s4, s5);
                s3 = s4;
              } else {
                peg$currPos = s3;
                s3 = peg$FAILED;
              }
            } else {
              peg$currPos = s3;
              s3 = peg$FAILED;
            }
          }
          while (s3 !== peg$FAILED) {
            s2.push(s3);
            if (peg$c57.test(input.charAt(peg$currPos))) {
              s3 = input.charAt(peg$currPos);
              peg$currPos++;
            } else {
              s3 = peg$FAILED;
              { peg$fail(peg$c58); }
            }
            if (s3 === peg$FAILED) {
              s3 = peg$currPos;
              if (input.charCodeAt(peg$currPos) === 92) {
                s4 = peg$c50;
                peg$currPos++;
              } else {
                s4 = peg$FAILED;
                { peg$fail(peg$c51); }
              }
              if (s4 !== peg$FAILED) {
                if (input.length > peg$currPos) {
                  s5 = input.charAt(peg$currPos);
                  peg$currPos++;
                } else {
                  s5 = peg$FAILED;
                  { peg$fail(peg$c52); }
                }
                if (s5 !== peg$FAILED) {
                  s4 = peg$c53(s4, s5);
                  s3 = s4;
                } else {
                  peg$currPos = s3;
                  s3 = peg$FAILED;
                }
              } else {
                peg$currPos = s3;
                s3 = peg$FAILED;
              }
            }
          }
          if (s2 !== peg$FAILED) {
            if (input.charCodeAt(peg$currPos) === 39) {
              s3 = peg$c55;
              peg$currPos++;
            } else {
              s3 = peg$FAILED;
              { peg$fail(peg$c56); }
            }
            if (s3 !== peg$FAILED) {
              s1 = peg$c54(s2);
              s0 = s1;
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsenumber() {
      var s0, s1, s2, s3;

      var key    = peg$currPos * 30 + 16,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = peg$currPos;
      s2 = [];
      if (peg$c59.test(input.charAt(peg$currPos))) {
        s3 = input.charAt(peg$currPos);
        peg$currPos++;
      } else {
        s3 = peg$FAILED;
        { peg$fail(peg$c60); }
      }
      while (s3 !== peg$FAILED) {
        s2.push(s3);
        if (peg$c59.test(input.charAt(peg$currPos))) {
          s3 = input.charAt(peg$currPos);
          peg$currPos++;
        } else {
          s3 = peg$FAILED;
          { peg$fail(peg$c60); }
        }
      }
      if (s2 !== peg$FAILED) {
        if (input.charCodeAt(peg$currPos) === 46) {
          s3 = peg$c42;
          peg$currPos++;
        } else {
          s3 = peg$FAILED;
          { peg$fail(peg$c43); }
        }
        if (s3 !== peg$FAILED) {
          s2 = [s2, s3];
          s1 = s2;
        } else {
          peg$currPos = s1;
          s1 = peg$FAILED;
        }
      } else {
        peg$currPos = s1;
        s1 = peg$FAILED;
      }
      if (s1 === peg$FAILED) {
        s1 = null;
      }
      if (s1 !== peg$FAILED) {
        s2 = [];
        if (peg$c59.test(input.charAt(peg$currPos))) {
          s3 = input.charAt(peg$currPos);
          peg$currPos++;
        } else {
          s3 = peg$FAILED;
          { peg$fail(peg$c60); }
        }
        if (s3 !== peg$FAILED) {
          while (s3 !== peg$FAILED) {
            s2.push(s3);
            if (peg$c59.test(input.charAt(peg$currPos))) {
              s3 = input.charAt(peg$currPos);
              peg$currPos++;
            } else {
              s3 = peg$FAILED;
              { peg$fail(peg$c60); }
            }
          }
        } else {
          s2 = peg$FAILED;
        }
        if (s2 !== peg$FAILED) {
          s1 = peg$c61(s1, s2);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsepath() {
      var s0, s1;

      var key    = peg$currPos * 30 + 17,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      s1 = peg$parseidentifierName();
      if (s1 !== peg$FAILED) {
        s1 = peg$c62(s1);
      }
      s0 = s1;

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsetype() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 18,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 5) === peg$c63) {
        s1 = peg$c63;
        peg$currPos += 5;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c64); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = [];
          if (peg$c65.test(input.charAt(peg$currPos))) {
            s4 = input.charAt(peg$currPos);
            peg$currPos++;
          } else {
            s4 = peg$FAILED;
            { peg$fail(peg$c66); }
          }
          if (s4 !== peg$FAILED) {
            while (s4 !== peg$FAILED) {
              s3.push(s4);
              if (peg$c65.test(input.charAt(peg$currPos))) {
                s4 = input.charAt(peg$currPos);
                peg$currPos++;
              } else {
                s4 = peg$FAILED;
                { peg$fail(peg$c66); }
              }
            }
          } else {
            s3 = peg$FAILED;
          }
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              if (input.charCodeAt(peg$currPos) === 41) {
                s5 = peg$c67;
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c68); }
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c69(s3);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseflags() {
      var s0, s1;

      var key    = peg$currPos * 30 + 19,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = [];
      if (peg$c70.test(input.charAt(peg$currPos))) {
        s1 = input.charAt(peg$currPos);
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c71); }
      }
      if (s1 !== peg$FAILED) {
        while (s1 !== peg$FAILED) {
          s0.push(s1);
          if (peg$c70.test(input.charAt(peg$currPos))) {
            s1 = input.charAt(peg$currPos);
            peg$currPos++;
          } else {
            s1 = peg$FAILED;
            { peg$fail(peg$c71); }
          }
        }
      } else {
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseregex() {
      var s0, s1, s2, s3, s4;

      var key    = peg$currPos * 30 + 20,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 47) {
        s1 = peg$c72;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c73); }
      }
      if (s1 !== peg$FAILED) {
        s2 = [];
        if (peg$c74.test(input.charAt(peg$currPos))) {
          s3 = input.charAt(peg$currPos);
          peg$currPos++;
        } else {
          s3 = peg$FAILED;
          { peg$fail(peg$c75); }
        }
        if (s3 !== peg$FAILED) {
          while (s3 !== peg$FAILED) {
            s2.push(s3);
            if (peg$c74.test(input.charAt(peg$currPos))) {
              s3 = input.charAt(peg$currPos);
              peg$currPos++;
            } else {
              s3 = peg$FAILED;
              { peg$fail(peg$c75); }
            }
          }
        } else {
          s2 = peg$FAILED;
        }
        if (s2 !== peg$FAILED) {
          if (input.charCodeAt(peg$currPos) === 47) {
            s3 = peg$c72;
            peg$currPos++;
          } else {
            s3 = peg$FAILED;
            { peg$fail(peg$c73); }
          }
          if (s3 !== peg$FAILED) {
            s4 = peg$parseflags();
            if (s4 === peg$FAILED) {
              s4 = null;
            }
            if (s4 !== peg$FAILED) {
              s1 = peg$c76(s2, s4);
              s0 = s1;
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsefield() {
      var s0, s1, s2, s3, s4, s5, s6;

      var key    = peg$currPos * 30 + 21,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 46) {
        s1 = peg$c42;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c43); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parseidentifierName();
        if (s2 !== peg$FAILED) {
          s3 = [];
          s4 = peg$currPos;
          if (input.charCodeAt(peg$currPos) === 46) {
            s5 = peg$c42;
            peg$currPos++;
          } else {
            s5 = peg$FAILED;
            { peg$fail(peg$c43); }
          }
          if (s5 !== peg$FAILED) {
            s6 = peg$parseidentifierName();
            if (s6 !== peg$FAILED) {
              s5 = [s5, s6];
              s4 = s5;
            } else {
              peg$currPos = s4;
              s4 = peg$FAILED;
            }
          } else {
            peg$currPos = s4;
            s4 = peg$FAILED;
          }
          while (s4 !== peg$FAILED) {
            s3.push(s4);
            s4 = peg$currPos;
            if (input.charCodeAt(peg$currPos) === 46) {
              s5 = peg$c42;
              peg$currPos++;
            } else {
              s5 = peg$FAILED;
              { peg$fail(peg$c43); }
            }
            if (s5 !== peg$FAILED) {
              s6 = peg$parseidentifierName();
              if (s6 !== peg$FAILED) {
                s5 = [s5, s6];
                s4 = s5;
              } else {
                peg$currPos = s4;
                s4 = peg$FAILED;
              }
            } else {
              peg$currPos = s4;
              s4 = peg$FAILED;
            }
          }
          if (s3 !== peg$FAILED) {
            s1 = peg$c77(s2, s3);
            s0 = s1;
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsenegation() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 22,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 5) === peg$c78) {
        s1 = peg$c78;
        peg$currPos += 5;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c79); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = peg$parseselectors();
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              if (input.charCodeAt(peg$currPos) === 41) {
                s5 = peg$c67;
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c68); }
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c80(s3);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsematches() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 23,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 9) === peg$c81) {
        s1 = peg$c81;
        peg$currPos += 9;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c82); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = peg$parseselectors();
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              if (input.charCodeAt(peg$currPos) === 41) {
                s5 = peg$c67;
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c68); }
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c83(s3);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsehas() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 24,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 5) === peg$c84) {
        s1 = peg$c84;
        peg$currPos += 5;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c85); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = peg$parseselectors();
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              if (input.charCodeAt(peg$currPos) === 41) {
                s5 = peg$c67;
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c68); }
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c86(s3);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsefirstChild() {
      var s0, s1;

      var key    = peg$currPos * 30 + 25,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 12) === peg$c87) {
        s1 = peg$c87;
        peg$currPos += 12;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c88); }
      }
      if (s1 !== peg$FAILED) {
        s1 = peg$c89();
      }
      s0 = s1;

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parselastChild() {
      var s0, s1;

      var key    = peg$currPos * 30 + 26,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 11) === peg$c90) {
        s1 = peg$c90;
        peg$currPos += 11;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c91); }
      }
      if (s1 !== peg$FAILED) {
        s1 = peg$c92();
      }
      s0 = s1;

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsenthChild() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 27,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 11) === peg$c93) {
        s1 = peg$c93;
        peg$currPos += 11;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c94); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = [];
          if (peg$c59.test(input.charAt(peg$currPos))) {
            s4 = input.charAt(peg$currPos);
            peg$currPos++;
          } else {
            s4 = peg$FAILED;
            { peg$fail(peg$c60); }
          }
          if (s4 !== peg$FAILED) {
            while (s4 !== peg$FAILED) {
              s3.push(s4);
              if (peg$c59.test(input.charAt(peg$currPos))) {
                s4 = input.charAt(peg$currPos);
                peg$currPos++;
              } else {
                s4 = peg$FAILED;
                { peg$fail(peg$c60); }
              }
            }
          } else {
            s3 = peg$FAILED;
          }
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              if (input.charCodeAt(peg$currPos) === 41) {
                s5 = peg$c67;
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c68); }
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c95(s3);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parsenthLastChild() {
      var s0, s1, s2, s3, s4, s5;

      var key    = peg$currPos * 30 + 28,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.substr(peg$currPos, 16) === peg$c96) {
        s1 = peg$c96;
        peg$currPos += 16;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c97); }
      }
      if (s1 !== peg$FAILED) {
        s2 = peg$parse_();
        if (s2 !== peg$FAILED) {
          s3 = [];
          if (peg$c59.test(input.charAt(peg$currPos))) {
            s4 = input.charAt(peg$currPos);
            peg$currPos++;
          } else {
            s4 = peg$FAILED;
            { peg$fail(peg$c60); }
          }
          if (s4 !== peg$FAILED) {
            while (s4 !== peg$FAILED) {
              s3.push(s4);
              if (peg$c59.test(input.charAt(peg$currPos))) {
                s4 = input.charAt(peg$currPos);
                peg$currPos++;
              } else {
                s4 = peg$FAILED;
                { peg$fail(peg$c60); }
              }
            }
          } else {
            s3 = peg$FAILED;
          }
          if (s3 !== peg$FAILED) {
            s4 = peg$parse_();
            if (s4 !== peg$FAILED) {
              if (input.charCodeAt(peg$currPos) === 41) {
                s5 = peg$c67;
                peg$currPos++;
              } else {
                s5 = peg$FAILED;
                { peg$fail(peg$c68); }
              }
              if (s5 !== peg$FAILED) {
                s1 = peg$c98(s3);
                s0 = s1;
              } else {
                peg$currPos = s0;
                s0 = peg$FAILED;
              }
            } else {
              peg$currPos = s0;
              s0 = peg$FAILED;
            }
          } else {
            peg$currPos = s0;
            s0 = peg$FAILED;
          }
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }

    function peg$parseclass() {
      var s0, s1, s2;

      var key    = peg$currPos * 30 + 29,
          cached = peg$resultsCache[key];

      if (cached) {
        peg$currPos = cached.nextPos;

        return cached.result;
      }

      s0 = peg$currPos;
      if (input.charCodeAt(peg$currPos) === 58) {
        s1 = peg$c99;
        peg$currPos++;
      } else {
        s1 = peg$FAILED;
        { peg$fail(peg$c100); }
      }
      if (s1 !== peg$FAILED) {
        if (input.substr(peg$currPos, 9).toLowerCase() === peg$c101) {
          s2 = input.substr(peg$currPos, 9);
          peg$currPos += 9;
        } else {
          s2 = peg$FAILED;
          { peg$fail(peg$c102); }
        }
        if (s2 === peg$FAILED) {
          if (input.substr(peg$currPos, 10).toLowerCase() === peg$c103) {
            s2 = input.substr(peg$currPos, 10);
            peg$currPos += 10;
          } else {
            s2 = peg$FAILED;
            { peg$fail(peg$c104); }
          }
          if (s2 === peg$FAILED) {
            if (input.substr(peg$currPos, 11).toLowerCase() === peg$c105) {
              s2 = input.substr(peg$currPos, 11);
              peg$currPos += 11;
            } else {
              s2 = peg$FAILED;
              { peg$fail(peg$c106); }
            }
            if (s2 === peg$FAILED) {
              if (input.substr(peg$currPos, 8).toLowerCase() === peg$c107) {
                s2 = input.substr(peg$currPos, 8);
                peg$currPos += 8;
              } else {
                s2 = peg$FAILED;
                { peg$fail(peg$c108); }
              }
              if (s2 === peg$FAILED) {
                if (input.substr(peg$currPos, 7).toLowerCase() === peg$c109) {
                  s2 = input.substr(peg$currPos, 7);
                  peg$currPos += 7;
                } else {
                  s2 = peg$FAILED;
                  { peg$fail(peg$c110); }
                }
              }
            }
          }
        }
        if (s2 !== peg$FAILED) {
          s1 = peg$c111(s2);
          s0 = s1;
        } else {
          peg$currPos = s0;
          s0 = peg$FAILED;
        }
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }

      peg$resultsCache[key] = { nextPos: peg$currPos, result: s0 };

      return s0;
    }


      function nth(n) { return { type: 'nth-child', index: { type: 'literal', value: n } }; }
      function nthLast(n) { return { type: 'nth-last-child', index: { type: 'literal', value: n } }; }
      function strUnescape(s) {
        return s.replace(/\\(.)/g, function(match, ch) {
          switch(ch) {
            case 'b': return '\b';
            case 'f': return '\f';
            case 'n': return '\n';
            case 'r': return '\r';
            case 't': return '\t';
            case 'v': return '\v';
            default: return ch;
          }
        });
      }


    peg$result = peg$startRuleFunction();

    if (peg$result !== peg$FAILED && peg$currPos === input.length) {
      return peg$result;
    } else {
      if (peg$result !== peg$FAILED && peg$currPos < input.length) {
        peg$fail(peg$endExpectation());
      }

      throw peg$buildStructuredError(
        peg$maxFailExpected,
        peg$maxFailPos < input.length ? input.charAt(peg$maxFailPos) : null,
        peg$maxFailPos < input.length
          ? peg$computeLocation(peg$maxFailPos, peg$maxFailPos + 1)
          : peg$computeLocation(peg$maxFailPos, peg$maxFailPos)
      );
    }
  }

  return {
    SyntaxError: peg$SyntaxError,
    parse:       peg$parse
  };
});
});

/* vim: set sw=4 sts=4 : */

/**
* @typedef {"LEFT_SIDE"|"RIGHT_SIDE"} Side
*/

const LEFT_SIDE = 'LEFT_SIDE';
const RIGHT_SIDE = 'RIGHT_SIDE';

/**
 * @external AST
 * @see https://esprima.readthedocs.io/en/latest/syntax-tree-format.html
 */

/**
 * One of the rules of `grammar.pegjs`
 * @typedef {PlainObject} SelectorAST
 * @see grammar.pegjs
*/

/**
 * The `sequence` production of `grammar.pegjs`
 * @typedef {PlainObject} SelectorSequenceAST
*/

/**
 * Get the value of a property which may be multiple levels down
 * in the object.
 * @param {?PlainObject} obj
 * @param {string} key
 * @returns {undefined|boolean|string|number|external:AST}
 */
function getPath(obj, key) {
    const keys = key.split('.');
    for (let i = 0; i < keys.length; i++) {
        if (obj == null) { return obj; }
        obj = obj[keys[i]];
    }
    return obj;
}

/**
 * Determine whether `node` can be reached by following `path`,
 * starting at `ancestor`.
 * @param {?external:AST} node
 * @param {?external:AST} ancestor
 * @param {string[]} path
 * @returns {boolean}
 */
function inPath(node, ancestor, path) {
    if (path.length === 0) { return node === ancestor; }
    if (ancestor == null) { return false; }
    const field = ancestor[path[0]];
    const remainingPath = path.slice(1);
    if (Array.isArray(field)) {
        for (let i = 0, l = field.length; i < l; ++i) {
            if (inPath(node, field[i], remainingPath)) { return true; }
        }
        return false;
    } else {
        return inPath(node, field, remainingPath);
    }
}

/**
 * Given a `node` and its ancestors, determine if `node` is matched
 * by `selector`.
 * @param {?external:AST} node
 * @param {?SelectorAST} selector
 * @param {external:AST[]} [ancestry=[]]
 * @throws {Error} Unknowns (operator, class name, selector type, or
 * selector value type)
 * @returns {boolean}
 */
function matches(node, selector, ancestry) {
    if (!selector) { return true; }
    if (!node) { return false; }
    if (!ancestry) { ancestry = []; }

    switch(selector.type) {
        case 'wildcard':
            return true;

        case 'identifier':
            return selector.value.toLowerCase() === node.type.toLowerCase();

        case 'field': {
            const path = selector.name.split('.');
            const ancestor = ancestry[path.length - 1];
            return inPath(node, ancestor, path);

        }
        case 'matches':
            for (let i = 0, l = selector.selectors.length; i < l; ++i) {
                if (matches(node, selector.selectors[i], ancestry)) { return true; }
            }
            return false;

        case 'compound':
            for (let i = 0, l = selector.selectors.length; i < l; ++i) {
                if (!matches(node, selector.selectors[i], ancestry)) { return false; }
            }
            return true;

        case 'not':
            for (let i = 0, l = selector.selectors.length; i < l; ++i) {
                if (matches(node, selector.selectors[i], ancestry)) { return false; }
            }
            return true;

        case 'has': {
            const collector = [];
            for (let i = 0, l = selector.selectors.length; i < l; ++i) {
                const a = [];
                estraverse.traverse(node, {
                    enter (node, parent) {
                        if (parent != null) { a.unshift(parent); }
                        if (matches(node, selector.selectors[i], a)) {
                            collector.push(node);
                        }
                    },
                    leave () { a.shift(); },
                    fallback: 'iteration'
                });
            }
            return collector.length !== 0;

        }
        case 'child':
            if (matches(node, selector.right, ancestry)) {
                return matches(ancestry[0], selector.left, ancestry.slice(1));
            }
            return false;

        case 'descendant':
            if (matches(node, selector.right, ancestry)) {
                for (let i = 0, l = ancestry.length; i < l; ++i) {
                    if (matches(ancestry[i], selector.left, ancestry.slice(i + 1))) {
                        return true;
                    }
                }
            }
            return false;

        case 'attribute': {
            const p = getPath(node, selector.name);
            switch (selector.operator) {
                case void 0:
                    return p != null;
                case '=':
                    switch (selector.value.type) {
                        case 'regexp': return typeof p === 'string' && selector.value.value.test(p);
                        case 'literal': return `${selector.value.value}` === `${p}`;
                        case 'type': return selector.value.value === typeof p;
                    }
                    throw new Error(`Unknown selector value type: ${selector.value.type}`);
                case '!=':
                    switch (selector.value.type) {
                        case 'regexp': return !selector.value.value.test(p);
                        case 'literal': return `${selector.value.value}` !== `${p}`;
                        case 'type': return selector.value.value !== typeof p;
                    }
                    throw new Error(`Unknown selector value type: ${selector.value.type}`);
                case '<=': return p <= selector.value.value;
                case '<': return p < selector.value.value;
                case '>': return p > selector.value.value;
                case '>=': return p >= selector.value.value;
            }
            throw new Error(`Unknown operator: ${selector.operator}`);
        }
        case 'sibling':
            return matches(node, selector.right, ancestry) &&
                sibling(node, selector.left, ancestry, LEFT_SIDE) ||
                selector.left.subject &&
                matches(node, selector.left, ancestry) &&
                sibling(node, selector.right, ancestry, RIGHT_SIDE);
        case 'adjacent':
            return matches(node, selector.right, ancestry) &&
                adjacent(node, selector.left, ancestry, LEFT_SIDE) ||
                selector.right.subject &&
                matches(node, selector.left, ancestry) &&
                adjacent(node, selector.right, ancestry, RIGHT_SIDE);

        case 'nth-child':
            return matches(node, selector.right, ancestry) &&
                nthChild(node, ancestry, function () {
                    return selector.index.value - 1;
                });

        case 'nth-last-child':
            return matches(node, selector.right, ancestry) &&
                nthChild(node, ancestry, function (length) {
                    return length - selector.index.value;
                });

        case 'class':
            switch(selector.name.toLowerCase()){
                case 'statement':
                    if(node.type.slice(-9) === 'Statement') return true;
                    // fallthrough: interface Declaration <: Statement { }
                case 'declaration':
                    return node.type.slice(-11) === 'Declaration';
                case 'pattern':
                    if(node.type.slice(-7) === 'Pattern') return true;
                    // fallthrough: interface Expression <: Node, Pattern { }
                case 'expression':
                    return node.type.slice(-10) === 'Expression' ||
                        node.type.slice(-7) === 'Literal' ||
                        (
                            node.type === 'Identifier' &&
                            (ancestry.length === 0 || ancestry[0].type !== 'MetaProperty')
                        ) ||
                        node.type === 'MetaProperty';
                case 'function':
                    return node.type === 'FunctionDeclaration' ||
                        node.type === 'FunctionExpression' ||
                        node.type === 'ArrowFunctionExpression';
            }
            throw new Error(`Unknown class name: ${selector.name}`);
    }

    throw new Error(`Unknown selector type: ${selector.type}`);
}

/**
 * Determines if the given node has a sibling that matches the
 * given selector.
 * @param {external:AST} node
 * @param {SelectorSequenceAST} selector
 * @param {external:AST[]} ancestry
 * @param {Side} side
 * @returns {boolean}
 */
function sibling(node, selector, ancestry, side) {
    const [parent] = ancestry;
    if (!parent) { return false; }
    const keys = estraverse.VisitorKeys[parent.type];
    for (let i = 0, l = keys.length; i < l; ++i) {
        const listProp = parent[keys[i]];
        if (Array.isArray(listProp)) {
            const startIndex = listProp.indexOf(node);
            if (startIndex < 0) { continue; }
            let lowerBound, upperBound;
            if (side === LEFT_SIDE) {
                lowerBound = 0;
                upperBound = startIndex;
            } else {
                lowerBound = startIndex + 1;
                upperBound = listProp.length;
            }
            for (let k = lowerBound; k < upperBound; ++k) {
                if (matches(listProp[k], selector, ancestry)) {
                    return true;
                }
            }
        }
    }
    return false;
}

/**
 * Determines if the given node has an adjacent sibling that matches
 * the given selector.
 * @param {external:AST} node
 * @param {SelectorSequenceAST} selector
 * @param {external:AST[]} ancestry
 * @param {Side} side
 * @returns {boolean}
 */
function adjacent(node, selector, ancestry, side) {
    const [parent] = ancestry;
    if (!parent) { return false; }
    const keys = estraverse.VisitorKeys[parent.type];
    for (let i = 0, l = keys.length; i < l; ++i) {
        const listProp = parent[keys[i]];
        if (Array.isArray(listProp)) {
            const idx = listProp.indexOf(node);
            if (idx < 0) { continue; }
            if (side === LEFT_SIDE && idx > 0 && matches(listProp[idx - 1], selector, ancestry)) {
                return true;
            }
            if (side === RIGHT_SIDE && idx < listProp.length - 1 && matches(listProp[idx + 1], selector, ancestry)) {
                return true;
            }
        }
    }
    return false;
}

/**
* @callback IndexFunction
* @param {Integer} len Containing list's length
* @returns {Integer}
*/

/**
 * Determines if the given node is the nth child, determined by
 * `idxFn`, which is given the containing list's length.
 * @param {external:AST} node
 * @param {external:AST[]} ancestry
 * @param {IndexFunction} idxFn
 * @returns {boolean}
 */
function nthChild(node, ancestry, idxFn) {
    const [parent] = ancestry;
    if (!parent) { return false; }
    const keys = estraverse.VisitorKeys[parent.type];
    for (let i = 0, l = keys.length; i < l; ++i) {
        const listProp = parent[keys[i]];
        if (Array.isArray(listProp)) {
            const idx = listProp.indexOf(node);
            if (idx >= 0 && idx === idxFn(listProp.length)) { return true; }
        }
    }
    return false;
}

/**
 * For each selector node marked as a subject, find the portion of the
 * selector that the subject must match.
 * @param {SelectorAST} selector
 * @param {SelectorAST} [ancestor] Defaults to `selector`
 * @returns {SelectorAST[]}
 */
function subjects(selector, ancestor) {
    if (selector == null || typeof selector != 'object') { return []; }
    if (ancestor == null) { ancestor = selector; }
    const results = selector.subject ? [ancestor] : [];
    for (const [p, sel] of Object.entries(selector)) {
        results.push(...subjects(sel, p === 'left' ? sel : ancestor));
    }
    return results;
}

/**
 * From a JS AST and a selector AST, collect all JS AST nodes that
 * match the selector.
 * @param {external:AST} ast
 * @param {?SelectorAST} selector
 * @returns {external:AST[]}
 */
function match(ast, selector) {
    const ancestry = [], results = [];
    if (!selector) { return results; }
    const altSubjects = subjects(selector);
    estraverse.traverse(ast, {
        enter (node, parent) {
            if (parent != null) { ancestry.unshift(parent); }
            if (matches(node, selector, ancestry)) {
                if (altSubjects.length) {
                    for (let i = 0, l = altSubjects.length; i < l; ++i) {
                        if (matches(node, altSubjects[i], ancestry)) { results.push(node); }
                        for (let k = 0, m = ancestry.length; k < m; ++k) {
                            if (matches(ancestry[k], altSubjects[i], ancestry.slice(k + 1))) {
                                results.push(ancestry[k]);
                            }
                        }
                    }
                } else {
                    results.push(node);
                }
            }
        },
        leave () { ancestry.shift(); },
        fallback: 'iteration'
    });
    return results;
}

/**
 * Parse a selector string and return its AST.
 * @param {string} selector
 * @returns {SelectorAST}
 */
function parse(selector) {
    return parser.parse(selector);
}

/**
 * Query the code AST using the selector string.
 * @param {external:AST} ast
 * @param {string} selector
 * @returns {external:AST[]}
 */
function query(ast, selector) {
    return match(ast, parse(selector));
}

query.parse = parse;
query.match = match;
query.matches = matches;
query.query = query;

export default query;