acorn.js

/**
 * @license
 * Copyright 2012 Marijn Haverbeke
 * SPDX-License-Identifier: MIT
 */

// Acorn is a tiny, fast JavaScript parser written in JavaScript.
//
// Acorn was written by Marijn Haverbeke and released under an MIT
// license. The Unicode regexps (for identifiers and whitespace) were
// taken from [Esprima](http://esprima.org) by Ariya Hidayat.
//
// Git repositories for Acorn are available at
//
//     http://marijnhaverbeke.nl/git/acorn
//     https://github.com/marijnh/acorn.git
//
// Please use the [github bug tracker][ghbt] to report issues.
//
// [ghbt]: https://github.com/marijnh/acorn/issues
//
// This file defines the main parser interface. The library also comes
// with a [error-tolerant parser][dammit] and an
// [abstract syntax tree walker][walk], defined in other files.
//
// [dammit]: acorn_loose.js
// [walk]: util/walk.js

(function(root, mod) {
  if (typeof exports === "object" && typeof module === "object") return mod(exports); // CommonJS
  if (typeof define === "function" && define.amd) return define(["exports"], mod); // AMD
  mod(root.acorn || (root.acorn = {})); // Plain browser env
})((typeof globalThis === 'undefined') ? this || window : globalThis, function(exports) {
  "use strict";

  exports.version = "0.5.0";
  // Plus additional edits marked with 'JS-Interpreter change' comments.

  // JS-Interpreter change:
  // For global object, use 'globalThis' if it exists,
  // fall back to 'this' or 'window'.  Same logic as in JS-Interpreter.
  // -- Neil Fraser, March 2024.

  // JS-Interpreter change:
  // Added JSDoc type definitions.
  // -- Neil Fraser, July 2023.

  // JS-Interpreter change:
  // No longer exporting defaultOptions, getLineInfo, tokenize, tokTypes,
  // isIdentifierStart, and isIdentifierChar.  Not used by JS-Interpreter.
  // -- Neil Fraser, February 2023.

  // The main exported interface (under `self.acorn` when in the
  // browser) is a `parse` function that takes a code string and
  // returns an abstract syntax tree as specified by [Mozilla parser
  // API][api], with the caveat that the SpiderMonkey-specific syntax
  // (`let`, `yield`, inline XML, etc) is not recognized.
  //
  // [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API

  /** @type {!Object|undefined} */
  var options;

  /** @type {string} */
  var input = '';
  /** @type {number|undefined} */
  var inputLen;
  /** @type {*} */
  var sourceFile;

  /**
   * @param {string} inpt
   * @param {Object=} opts
   * @returns
   */
  exports.parse = function(inpt, opts) {
    input = String(inpt);
    inputLen = input.length;
    setOptions(opts);
    initTokenState();
    return parseTopLevel(options.program);
  };

  // A second optional argument can be given to further configure
  // the parser process. These options are recognized:

  var defaultOptions = {
    // JS-Interpreter change:
    // `ecmaVersion` option has been removed along with all cases where
    // it is checked.  In this version of Acorn it was limited to 3 or 5,
    // and there's no use case for 3 with JS-Interpreter.
    // -- Neil Fraser, December 2022.

    // Turn on `strictSemicolons` to prevent the parser from doing
    // automatic semicolon insertion.
    strictSemicolons: false,
    // When `allowTrailingCommas` is false, the parser will not allow
    // trailing commas in array and object literals.
    allowTrailingCommas: true,
    // By default, reserved words are not enforced. Enable
    // `forbidReserved` to enforce them. When this option has the
    // value "everywhere", reserved words and keywords can also not be
    // used as property names.
    forbidReserved: false,
    // When enabled, a return at the top level is not considered an
    // error.
    allowReturnOutsideFunction: false,
    // When `locations` is on, `loc` properties holding objects with
    // `start` and `end` properties in `{line, column}` form (with
    // line being 1-based and column 0-based) will be attached to the
    // nodes.
    locations: false,
    // A function can be passed as `onComment` option, which will
    // cause Acorn to call that function with `(block, text, start,
    // end)` parameters whenever a comment is skipped. `block` is a
    // boolean indicating whether this is a block (`/* */`) comment,
    // `text` is the content of the comment, and `start` and `end` are
    // character offsets that denote the start and end of the comment.
    // When the `locations` option is on, two more parameters are
    // passed, the full `{line, column}` locations of the start and
    // end of the comments. Note that you are not allowed to call the
    // parser from the callback—that will corrupt its internal state.
    onComment: null,
    // Nodes have their start and end characters offsets recorded in
    // `start` and `end` properties (directly on the node, rather than
    // the `loc` object, which holds line/column data. To also add a
    // [semi-standardized][range] `range` property holding a `[start,
    // end]` array with the same numbers, set the `ranges` option to
    // `true`.
    //
    // [range]: https://bugzilla.mozilla.org/show_bug.cgi?id=745678
    ranges: false,
    // It is possible to parse multiple files into a single AST by
    // passing the tree produced by parsing the first file as
    // `program` option in subsequent parses. This will add the
    // toplevel forms of the parsed file to the `Program` (top) node
    // of an existing parse tree.
    program: null,
    // When `locations` is on, you can pass this to record the source
    // file in every node's `loc` object.
    sourceFile: null,
    // This value, if given, is stored in every node, whether
    // `locations` is on or off.
    directSourceFile: null,
  };

  /**
   * @param {Object|undefined} opts
   */
  function setOptions(opts) {
    options = opts || {};
    for (var opt in defaultOptions) {
      if (!Object.prototype.hasOwnProperty.call(options, opt)) {
        options[opt] = defaultOptions[opt];
      }
    }
    sourceFile = options.sourceFile;
  }

  /**
   * The `getLineInfo` function is mostly useful when the
   * `locations` option is off (for performance reasons) and you
   * want to find the line/column position for a given character
   * offset. `input` should be the code string that the offset refers
   * into.
   *
   * @param {string} input
   * @param {number} offset
   * @returns {!Object}
   */
  var getLineInfo = function(input, offset) {
    for (var line = 1, cur = 0;;) {
      lineBreak.lastIndex = cur;
      var match = lineBreak.exec(input);
      if (match && match.index < offset) {
        ++line;
        cur = match.index + match[0].length;
      } else {
        break;
      }
    }
    return {line: line, column: offset - cur};
  };

  // JS-Interpreter change:
  // tokenize function never used.  Removed.
  // -- Neil Fraser, February 2023.

  // State is kept in (closure-)global variables. We already saw the
  // `options`, `input`, and `inputLen` variables above.

  /**
   * The current position of the tokenizer in the input.
   * @type {number}
   */
  var tokPos = 0;

  /**
   * The start offset of the current token.
   * @type {number}
   */
  var tokStart = 0;

  /**
   * The end offset of the current token.
   * @type {number}
   */
  var tokEnd = 0;

  /**
   * When `options.locations` is true, holds object
   * containing the token's start line/column pairs.
   * @type {!line_loc_t|undefined}
   */
  var tokStartLoc;

  /**
   * When `options.locations` is true, holds object
   * containing the token's end line/column pairs.
   * @type {!line_loc_t|undefined}
   */
  var tokEndLoc;

  /**
   * The type of the current token. Token types are objects,
   * named by variables against which they can be compared, and
   * holding properties that describe them (indicating, for example,
   * the precedence of an infix operator, and the original name of a
   * keyword token).
   * @type {!Object|undefined}
   */
  var tokType;

  /**
   * The value of the current token. The kind of value that's held in
   * `tokVal` depends on the type of the token. For literals, it is the
   * literal value, for operators, the operator name, and so on.
   * @type {*}
   */
  var tokVal;

  /**
   * Interal state for the tokenizer. To distinguish between division
   * operators and regular expressions, it remembers whether the last
   * token was one that is allowed to be followed by an expression.
   * (If it is, a slash is probably a regexp, if it isn't it's a
   * division operator. See the `parseStatement` function for a caveat.)
   * @type {boolean|undefined}
   */
  var tokRegexpAllowed;

  /**
   * When `options.locations` is true, `tokCurLine` is used to keep
   * track of the current line.
   * @type {number|undefined}
   */
  var tokCurLine;

  /**
   * When `options.locations` is true, `tokLineStart` is used to know
   * when a new line has been entered.
   * @type {number|undefined}
   */
  var tokLineStart;

  /**
   * The start of the position of the previous token, which is useful
   * when finishing a node and assigning its `end` position.
   * @type {number}
   */
  var lastStart = 0;

  /**
   * The end oy the position of the previous token, which is useful
   * when finishing a node and assigning its `end` position.
   * @type {number}
   */
  var lastEnd = 0;

  /**
   * Stores the position of the previous token, which is useful
   * when finishing a node and assigning its `end` position.
   * @type {!line_loc_t|undefined}
   */
  var lastEndLoc;

  /**
   * `inFunction` is used to reject `return` statements outside of functions.
   * @type {boolean|undefined}
   */
  var inFunction;

  /**
   * `labels` is used to verify that `break` and `continue` have somewhere
   * to jump to.
   * @type {!Array<!Object>|undefined}
   */
  var labels;

  /**
   * `strict` indicates whether strict mode is on.
   * @type {boolean|undefined}
   */
  var strict;

  /**
   * This function is used to raise exceptions on parse errors. It
   * takes an offset integer (into the current `input`) to indicate
   * the location of the error, attaches the position to the end
   * of the error message, and then raises a `SyntaxError` with that
   * message.
   *
   * @param {number} pos
   * @param {string} message
   * @throws {SyntaxError}
   */
  function raise(pos, message) {
    var loc = getLineInfo(input, pos);
    message += " (" + loc.line + ":" + loc.column + ")";
    var err = new SyntaxError(message);
    err.pos = pos;
    err.loc = loc;
    err.raisedAt = tokPos;
    throw err;
  }

  // Reused empty array added for node fields that are always empty.

  var empty = [];

  // ## Token types

  // The assignment of fine-grained, information-carrying type objects
  // allows the tokenizer to store the information it has about a
  // token in a way that is very cheap for the parser to look up.

  // All token type variables start with an underscore, to make them
  // easy to recognize.

  // These are the general types. The `type` property is only used to
  // make them recognizeable when debugging.

  var _num = {type: "num"};
  var _regexp = {type: "regexp"};
  var _string = {type: "string"};
  var _name = {type: "name"};
  var _eof = {type: "eof"};

  // Keyword tokens. The `keyword` property (also used in keyword-like
  // operators) indicates that the token originated from an
  // identifier-like word, which is used when parsing property names.
  //
  // The `beforeExpr` property is used to disambiguate between regular
  // expressions and divisions. It is set on all token types that can
  // be followed by an expression (thus, a slash after them would be a
  // regular expression).
  //
  // `isLoop` marks a keyword as starting a loop, which is important
  // to know when parsing a label, in order to allow or disallow
  // continue jumps to that label.

  var _break = {keyword: "break"};
  var _case = {keyword: "case", beforeExpr: true};
  var _catch = {keyword: "catch"};
  var _continue = {keyword: "continue"};
  var _debugger = {keyword: "debugger"};
  var _default = {keyword: "default"};
  var _do = {keyword: "do", isLoop: true};
  var _else = {keyword: "else", beforeExpr: true};
  var _finally = {keyword: "finally"};
  var _for = {keyword: "for", isLoop: true};
  var _function = {keyword: "function"};
  var _if = {keyword: "if"};
  var _return = {keyword: "return", beforeExpr: true};
  var _switch = {keyword: "switch"};
  var _throw = {keyword: "throw", beforeExpr: true};
  var _try = {keyword: "try"};
  var _var = {keyword: "var"};
  var _while = {keyword: "while", isLoop: true};
  var _with = {keyword: "with"};
  var _new = {keyword: "new", beforeExpr: true};
  var _this = {keyword: "this"};

  // The keywords that denote values.

  var _null = {keyword: "null", atomValue: null};
  var _true = {keyword: "true", atomValue: true};
  var _false = {keyword: "false", atomValue: false};

  // Some keywords are treated as regular operators. `in` sometimes
  // (when parsing `for`) needs to be tested against specifically, so
  // we assign a variable name to it for quick comparing.

  var _in = {keyword: "in", binop: 7, beforeExpr: true};

  // Map keyword names to token types.

  var keywordTypes = {
    "break": _break,
    "case": _case,
    "catch": _catch,
    "continue": _continue,
    "debugger": _debugger,
    "default": _default,
    "do": _do,
    "else": _else,
    "finally": _finally,
    "for": _for,
    "function": _function,
    "if": _if,
    "return": _return,
    "switch": _switch,
    "throw": _throw,
    "try": _try,
    "var": _var,
    "while": _while,
    "with": _with,
    "null": _null,
    "true": _true,
    "false": _false,
    "new": _new,
    "in": _in,
    "instanceof": {keyword: "instanceof", binop: 7, beforeExpr: true},
    "this": _this,
    "typeof": {keyword: "typeof", prefix: true, beforeExpr: true},
    "void": {keyword: "void", prefix: true, beforeExpr: true},
    "delete": {keyword: "delete", prefix: true, beforeExpr: true},
  };

  // Punctuation token types. Again, the `type` property is purely for debugging.

  var _bracketL = {type: "[", beforeExpr: true};
  var _bracketR = {type: "]"};
  var _braceL = {type: "{", beforeExpr: true};
  var _braceR = {type: "}"};
  var _parenL = {type: "(", beforeExpr: true};
  var _parenR = {type: ")"};
  var _comma = {type: ",", beforeExpr: true};
  var _semi = {type: ";", beforeExpr: true};
  var _colon = {type: ":", beforeExpr: true};
  var _dot = {type: "."};
  var _question = {type: "?", beforeExpr: true};

  // Operators. These carry several kinds of properties to help the
  // parser use them properly (the presence of these properties is
  // what categorizes them as operators).
  //
  // `binop`, when present, specifies that this operator is a binary
  // operator, and will refer to its precedence.
  //
  // `prefix` and `postfix` mark the operator as a prefix or postfix
  // unary operator. `isUpdate` specifies that the node produced by
  // the operator should be of type UpdateExpression rather than
  // simply UnaryExpression (`++` and `--`).
  //
  // `isAssign` marks all of `=`, `+=`, `-=` etcetera, which act as
  // binary operators with a very low precedence, that should result
  // in AssignmentExpression nodes.

  var _slash = {binop: 10, beforeExpr: true};
  var _eq = {isAssign: true, beforeExpr: true};
  var _assign = {isAssign: true, beforeExpr: true};
  var _incDec = {postfix: true, prefix: true, isUpdate: true};
  var _prefix = {prefix: true, beforeExpr: true};
  var _logicalOR = {binop: 1, beforeExpr: true};
  var _logicalAND = {binop: 2, beforeExpr: true};
  var _bitwiseOR = {binop: 3, beforeExpr: true};
  var _bitwiseXOR = {binop: 4, beforeExpr: true};
  var _bitwiseAND = {binop: 5, beforeExpr: true};
  var _equality = {binop: 6, beforeExpr: true};
  var _relational = {binop: 7, beforeExpr: true};
  var _bitShift = {binop: 8, beforeExpr: true};
  var _plusMin = {binop: 9, prefix: true, beforeExpr: true};
  var _multiplyModulo = {binop: 10, beforeExpr: true};

  // JS-Interpreter change:
  // tokTypes map never used.  Removed.
  // -- Neil Fraser, February 2023.

  // JS-Interpreter change:
  // Acorn's original code built up functions using strings for maximum efficiency.
  // However, this triggered a CSP unsafe-eval requirement.  Here's a slower, but
  // simpler approach.  -- Neil Fraser, January 2022.
  // https://github.com/NeilFraser/JS-Interpreter/issues/228

  /**
   * @param {string} words
   * @returns {function(*): boolean}
   */
  function makePredicate(words) {
    var wordList = words.split(" ");
    var set = Object.create(null);
    for (var i = 0; i < wordList.length; i++) {
      set[wordList[i]] = true;
    }
    return function(str) {
      return set[str] || false;
    };
  }

  // ECMAScript 5 reserved words.

  var isReservedWord5 = makePredicate("class enum extends super const export import");

  // The additional reserved words in strict mode.

  var isStrictReservedWord = makePredicate("implements interface let package private protected public static yield");

  // The forbidden variable names in strict mode.

  var isStrictBadIdWord = makePredicate("eval arguments");

  // And the keywords.

  var isKeyword = makePredicate("break case catch continue debugger default do else finally for function if return switch throw try var while with null true false instanceof typeof void delete new in this");

  // ## Character categories

  // Big ugly regular expressions that match characters in the
  // whitespace, identifier, and identifier-start categories. These
  // are only applied when a character is found to actually have a
  // code point above 128.

  var nonASCIIwhitespace = /[\u1680\u180e\u2000-\u200a\u202f\u205f\u3000\ufeff]/;
  var nonASCIIidentifierStartChars = "\xaa\xb5\xba\xc0-\xd6\xd8-\xf6\xf8-\u02c1\u02c6-\u02d1\u02e0-\u02e4\u02ec\u02ee\u0370-\u0374\u0376\u0377\u037a-\u037d\u0386\u0388-\u038a\u038c\u038e-\u03a1\u03a3-\u03f5\u03f7-\u0481\u048a-\u0527\u0531-\u0556\u0559\u0561-\u0587\u05d0-\u05ea\u05f0-\u05f2\u0620-\u064a\u066e\u066f\u0671-\u06d3\u06d5\u06e5\u06e6\u06ee\u06ef\u06fa-\u06fc\u06ff\u0710\u0712-\u072f\u074d-\u07a5\u07b1\u07ca-\u07ea\u07f4\u07f5\u07fa\u0800-\u0815\u081a\u0824\u0828\u0840-\u0858\u08a0\u08a2-\u08ac\u0904-\u0939\u093d\u0950\u0958-\u0961\u0971-\u0977\u0979-\u097f\u0985-\u098c\u098f\u0990\u0993-\u09a8\u09aa-\u09b0\u09b2\u09b6-\u09b9\u09bd\u09ce\u09dc\u09dd\u09df-\u09e1\u09f0\u09f1\u0a05-\u0a0a\u0a0f\u0a10\u0a13-\u0a28\u0a2a-\u0a30\u0a32\u0a33\u0a35\u0a36\u0a38\u0a39\u0a59-\u0a5c\u0a5e\u0a72-\u0a74\u0a85-\u0a8d\u0a8f-\u0a91\u0a93-\u0aa8\u0aaa-\u0ab0\u0ab2\u0ab3\u0ab5-\u0ab9\u0abd\u0ad0\u0ae0\u0ae1\u0b05-\u0b0c\u0b0f\u0b10\u0b13-\u0b28\u0b2a-\u0b30\u0b32\u0b33\u0b35-\u0b39\u0b3d\u0b5c\u0b5d\u0b5f-\u0b61\u0b71\u0b83\u0b85-\u0b8a\u0b8e-\u0b90\u0b92-\u0b95\u0b99\u0b9a\u0b9c\u0b9e\u0b9f\u0ba3\u0ba4\u0ba8-\u0baa\u0bae-\u0bb9\u0bd0\u0c05-\u0c0c\u0c0e-\u0c10\u0c12-\u0c28\u0c2a-\u0c33\u0c35-\u0c39\u0c3d\u0c58\u0c59\u0c60\u0c61\u0c85-\u0c8c\u0c8e-\u0c90\u0c92-\u0ca8\u0caa-\u0cb3\u0cb5-\u0cb9\u0cbd\u0cde\u0ce0\u0ce1\u0cf1\u0cf2\u0d05-\u0d0c\u0d0e-\u0d10\u0d12-\u0d3a\u0d3d\u0d4e\u0d60\u0d61\u0d7a-\u0d7f\u0d85-\u0d96\u0d9a-\u0db1\u0db3-\u0dbb\u0dbd\u0dc0-\u0dc6\u0e01-\u0e30\u0e32\u0e33\u0e40-\u0e46\u0e81\u0e82\u0e84\u0e87\u0e88\u0e8a\u0e8d\u0e94-\u0e97\u0e99-\u0e9f\u0ea1-\u0ea3\u0ea5\u0ea7\u0eaa\u0eab\u0ead-\u0eb0\u0eb2\u0eb3\u0ebd\u0ec0-\u0ec4\u0ec6\u0edc-\u0edf\u0f00\u0f40-\u0f47\u0f49-\u0f6c\u0f88-\u0f8c\u1000-\u102a\u103f\u1050-\u1055\u105a-\u105d\u1061\u1065\u1066\u106e-\u1070\u1075-\u1081\u108e\u10a0-\u10c5\u10c7\u10cd\u10d0-\u10fa\u10fc-\u1248\u124a-\u124d\u1250-\u1256\u1258\u125a-\u125d\u1260-\u1288\u128a-\u128d\u1290-\u12b0\u12b2-\u12b5\u12b8-\u12be\u12c0\u12c2-\u12c5\u12c8-\u12d6\u12d8-\u1310\u1312-\u1315\u1318-\u135a\u1380-\u138f\u13a0-\u13f4\u1401-\u166c\u166f-\u167f\u1681-\u169a\u16a0-\u16ea\u16ee-\u16f0\u1700-\u170c\u170e-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176c\u176e-\u1770\u1780-\u17b3\u17d7\u17dc\u1820-\u1877\u1880-\u18a8\u18aa\u18b0-\u18f5\u1900-\u191c\u1950-\u196d\u1970-\u1974\u1980-\u19ab\u19c1-\u19c7\u1a00-\u1a16\u1a20-\u1a54\u1aa7\u1b05-\u1b33\u1b45-\u1b4b\u1b83-\u1ba0\u1bae\u1baf\u1bba-\u1be5\u1c00-\u1c23\u1c4d-\u1c4f\u1c5a-\u1c7d\u1ce9-\u1cec\u1cee-\u1cf1\u1cf5\u1cf6\u1d00-\u1dbf\u1e00-\u1f15\u1f18-\u1f1d\u1f20-\u1f45\u1f48-\u1f4d\u1f50-\u1f57\u1f59\u1f5b\u1f5d\u1f5f-\u1f7d\u1f80-\u1fb4\u1fb6-\u1fbc\u1fbe\u1fc2-\u1fc4\u1fc6-\u1fcc\u1fd0-\u1fd3\u1fd6-\u1fdb\u1fe0-\u1fec\u1ff2-\u1ff4\u1ff6-\u1ffc\u2071\u207f\u2090-\u209c\u2102\u2107\u210a-\u2113\u2115\u2119-\u211d\u2124\u2126\u2128\u212a-\u212d\u212f-\u2139\u213c-\u213f\u2145-\u2149\u214e\u2160-\u2188\u2c00-\u2c2e\u2c30-\u2c5e\u2c60-\u2ce4\u2ceb-\u2cee\u2cf2\u2cf3\u2d00-\u2d25\u2d27\u2d2d\u2d30-\u2d67\u2d6f\u2d80-\u2d96\u2da0-\u2da6\u2da8-\u2dae\u2db0-\u2db6\u2db8-\u2dbe\u2dc0-\u2dc6\u2dc8-\u2dce\u2dd0-\u2dd6\u2dd8-\u2dde\u2e2f\u3005-\u3007\u3021-\u3029\u3031-\u3035\u3038-\u303c\u3041-\u3096\u309d-\u309f\u30a1-\u30fa\u30fc-\u30ff\u3105-\u312d\u3131-\u318e\u31a0-\u31ba\u31f0-\u31ff\u3400-\u4db5\u4e00-\u9fcc\ua000-\ua48c\ua4d0-\ua4fd\ua500-\ua60c\ua610-\ua61f\ua62a\ua62b\ua640-\ua66e\ua67f-\ua697\ua6a0-\ua6ef\ua717-\ua71f\ua722-\ua788\ua78b-\ua78e\ua790-\ua793\ua7a0-\ua7aa\ua7f8-\ua801\ua803-\ua805\ua807-\ua80a\ua80c-\ua822\ua840-\ua873\ua882-\ua8b3\ua8f2-\ua8f7\ua8fb\ua90a-\ua925\ua930-\ua946\ua960-\ua97c\ua984-\ua9b2\ua9cf\uaa00-\uaa28\uaa40-\uaa42\uaa44-\uaa4b\uaa60-\uaa76\uaa7a\uaa80-\uaaaf\uaab1\uaab5\uaab6\uaab9-\uaabd\uaac0\uaac2\uaadb-\uaadd\uaae0-\uaaea\uaaf2-\uaaf4\uab01-\uab06\uab09-\uab0e\uab11-\uab16\uab20-\uab26\uab28-\uab2e\uabc0-\uabe2\uac00-\ud7a3\ud7b0-\ud7c6\ud7cb-\ud7fb\uf900-\ufa6d\ufa70-\ufad9\ufb00-\ufb06\ufb13-\ufb17\ufb1d\ufb1f-\ufb28\ufb2a-\ufb36\ufb38-\ufb3c\ufb3e\ufb40\ufb41\ufb43\ufb44\ufb46-\ufbb1\ufbd3-\ufd3d\ufd50-\ufd8f\ufd92-\ufdc7\ufdf0-\ufdfb\ufe70-\ufe74\ufe76-\ufefc\uff21-\uff3a\uff41-\uff5a\uff66-\uffbe\uffc2-\uffc7\uffca-\uffcf\uffd2-\uffd7\uffda-\uffdc";
  var nonASCIIidentifierChars = "\u0300-\u036f\u0483-\u0487\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u0620-\u0649\u0672-\u06d3\u06e7-\u06e8\u06fb-\u06fc\u0730-\u074a\u0800-\u0814\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0840-\u0857\u08e4-\u08fe\u0900-\u0903\u093a-\u093c\u093e-\u094f\u0951-\u0957\u0962-\u0963\u0966-\u096f\u0981-\u0983\u09bc\u09be-\u09c4\u09c7\u09c8\u09d7\u09df-\u09e0\u0a01-\u0a03\u0a3c\u0a3e-\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a66-\u0a71\u0a75\u0a81-\u0a83\u0abc\u0abe-\u0ac5\u0ac7-\u0ac9\u0acb-\u0acd\u0ae2-\u0ae3\u0ae6-\u0aef\u0b01-\u0b03\u0b3c\u0b3e-\u0b44\u0b47\u0b48\u0b4b-\u0b4d\u0b56\u0b57\u0b5f-\u0b60\u0b66-\u0b6f\u0b82\u0bbe-\u0bc2\u0bc6-\u0bc8\u0bca-\u0bcd\u0bd7\u0be6-\u0bef\u0c01-\u0c03\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62-\u0c63\u0c66-\u0c6f\u0c82\u0c83\u0cbc\u0cbe-\u0cc4\u0cc6-\u0cc8\u0cca-\u0ccd\u0cd5\u0cd6\u0ce2-\u0ce3\u0ce6-\u0cef\u0d02\u0d03\u0d46-\u0d48\u0d57\u0d62-\u0d63\u0d66-\u0d6f\u0d82\u0d83\u0dca\u0dcf-\u0dd4\u0dd6\u0dd8-\u0ddf\u0df2\u0df3\u0e34-\u0e3a\u0e40-\u0e45\u0e50-\u0e59\u0eb4-\u0eb9\u0ec8-\u0ecd\u0ed0-\u0ed9\u0f18\u0f19\u0f20-\u0f29\u0f35\u0f37\u0f39\u0f41-\u0f47\u0f71-\u0f84\u0f86-\u0f87\u0f8d-\u0f97\u0f99-\u0fbc\u0fc6\u1000-\u1029\u1040-\u1049\u1067-\u106d\u1071-\u1074\u1082-\u108d\u108f-\u109d\u135d-\u135f\u170e-\u1710\u1720-\u1730\u1740-\u1750\u1772\u1773\u1780-\u17b2\u17dd\u17e0-\u17e9\u180b-\u180d\u1810-\u1819\u1920-\u192b\u1930-\u193b\u1951-\u196d\u19b0-\u19c0\u19c8-\u19c9\u19d0-\u19d9\u1a00-\u1a15\u1a20-\u1a53\u1a60-\u1a7c\u1a7f-\u1a89\u1a90-\u1a99\u1b46-\u1b4b\u1b50-\u1b59\u1b6b-\u1b73\u1bb0-\u1bb9\u1be6-\u1bf3\u1c00-\u1c22\u1c40-\u1c49\u1c5b-\u1c7d\u1cd0-\u1cd2\u1d00-\u1dbe\u1e01-\u1f15\u200c\u200d\u203f\u2040\u2054\u20d0-\u20dc\u20e1\u20e5-\u20f0\u2d81-\u2d96\u2de0-\u2dff\u3021-\u3028\u3099\u309a\ua640-\ua66d\ua674-\ua67d\ua69f\ua6f0-\ua6f1\ua7f8-\ua800\ua806\ua80b\ua823-\ua827\ua880-\ua881\ua8b4-\ua8c4\ua8d0-\ua8d9\ua8f3-\ua8f7\ua900-\ua909\ua926-\ua92d\ua930-\ua945\ua980-\ua983\ua9b3-\ua9c0\uaa00-\uaa27\uaa40-\uaa41\uaa4c-\uaa4d\uaa50-\uaa59\uaa7b\uaae0-\uaae9\uaaf2-\uaaf3\uabc0-\uabe1\uabec\uabed\uabf0-\uabf9\ufb20-\ufb28\ufe00-\ufe0f\ufe20-\ufe26\ufe33\ufe34\ufe4d-\ufe4f\uff10-\uff19\uff3f";
  var nonASCIIidentifierStart = new RegExp("[" + nonASCIIidentifierStartChars + "]");
  var nonASCIIidentifier = new RegExp("[" + nonASCIIidentifierStartChars + nonASCIIidentifierChars + "]");

  // Whether a single character denotes a newline.

  var newline = /[\n\r\u2028\u2029]/;

  // Matches a whole line break (where CRLF is considered a single
  // line break). Used to count lines.

  var lineBreak = /\r\n|[\n\r\u2028\u2029]/g;

  /**
   * Test whether a given character code starts an identifier.
   *
   * @param {number} code
   * @returns {boolean}
   */
  var isIdentifierStart = function(code) {
    if (code < 65) return code === 36;
    if (code < 91) return true;
    if (code < 97) return code === 95;
    if (code < 123) return true;
    return code >= 0xaa && nonASCIIidentifierStart.test(String.fromCharCode(code));
  };

  /**
   * Test whether a given character is part of an identifier.
   *
   * @param {number} code
   * @returns {boolean}
   */
  var isIdentifierChar = function(code) {
    if (code < 48) return code === 36;
    if (code < 58) return true;
    if (code < 65) return false;
    if (code < 91) return true;
    if (code < 97) return code === 95;
    if (code < 123) return true;
    return code >= 0xaa && nonASCIIidentifier.test(String.fromCharCode(code));
  };

  // ## Tokenizer

  /**
   * These are used when `options.locations` is on, for the
   * `tokStartLoc` and `tokEndLoc` properties.
   * @constructor
   */
  function line_loc_t() {
    this.line = tokCurLine;
    this.column = tokPos - tokLineStart;
  }

  /**
   * Reset the token state. Used at the start of a parse.
   */
  function initTokenState() {
    tokCurLine = 1;
    tokPos = tokLineStart = 0;
    tokRegexpAllowed = true;
    skipSpace();
  }

  /**
   * Called at the end of every token. Sets `tokEnd`, `tokVal`, and
   * `tokRegexpAllowed`, and skips the space after the token, so that
   * the next one's `tokStart` will point at the right position.
   *
   * @param {!Object} type
   * @param {*=} val
   */
  function finishToken(type, val) {
    tokEnd = tokPos;
    if (options.locations) {
      tokEndLoc = new line_loc_t();
    }
    tokType = type;
    skipSpace();
    tokVal = val;
    tokRegexpAllowed = type.beforeExpr;
  }

  function skipBlockComment() {
    var startLoc = options.onComment && options.locations && new line_loc_t();
    var start = tokPos;
    var end = input.indexOf("*/", tokPos += 2);
    if (end === -1) {
      raise(tokPos - 2, "Unterminated comment");
    }
    tokPos = end + 2;
    if (options.locations) {
      lineBreak.lastIndex = start;
      var match;
      while ((match = lineBreak.exec(input)) && match.index < tokPos) {
        ++tokCurLine;
        tokLineStart = match.index + match[0].length;
      }
    }
    if (options.onComment) {
      options.onComment(true, input.slice(start + 2, end), start, tokPos,
                        startLoc, options.locations && new line_loc_t());
    }
  }

  function skipLineComment() {
    var start = tokPos;
    var startLoc = options.onComment && options.locations && new line_loc_t();
    var ch = input.charCodeAt(tokPos += 2);
    while (tokPos < inputLen && ch !== 10 && ch !== 13 && ch !== 8232 && ch !== 8233) {
      ++tokPos;
      ch = input.charCodeAt(tokPos);
    }
    if (options.onComment) {
      options.onComment(false, input.slice(start + 2, tokPos), start, tokPos,
                        startLoc, options.locations && new line_loc_t());
    }
  }

  // Called at the start of the parse and after every token. Skips
  // whitespace and comments, and.

  function skipSpace() {
    while (tokPos < inputLen) {
      var ch = input.charCodeAt(tokPos);
      if (ch === 32) { // ' '
        ++tokPos;
      } else if (ch === 13) {
        ++tokPos;
        var next = input.charCodeAt(tokPos);
        if (next === 10) {
          ++tokPos;
        }
        if (options.locations) {
          ++tokCurLine;
          tokLineStart = tokPos;
        }
      } else if (ch === 10 || ch === 8232 || ch === 8233) {
        ++tokPos;
        if (options.locations) {
          ++tokCurLine;
          tokLineStart = tokPos;
        }
      } else if (ch > 8 && ch < 14) {
        ++tokPos;
      } else if (ch === 47) { // '/'
        var next = input.charCodeAt(tokPos + 1);
        if (next === 42) { // '*'
          skipBlockComment();
        } else if (next === 47) { // '/'
          skipLineComment();
        } else break;
      } else if (ch === 160) { // '\xa0'
        ++tokPos;
      } else if (ch >= 5760 && nonASCIIwhitespace.test(String.fromCharCode(ch))) {
        ++tokPos;
      } else {
        break;
      }
    }
  }

  // ### Token reading

  // This is the function that is called to fetch the next token. It
  // is somewhat obscure, because it works in character codes rather
  // than characters, and because operator parsing has been inlined
  // into it.
  //
  // All in the name of speed.
  //
  // The `forceRegexp` parameter is used in the one case where the
  // `tokRegexpAllowed` trick does not work. See `parseStatement`.

  function readToken_dot() {
    var next = input.charCodeAt(tokPos + 1);
    if (next >= 48 && next <= 57) {
      readNumber(true);
    } else {
      ++tokPos;
      finishToken(_dot);
    }
  }

  function readToken_slash() {  // '/'
    var next = input.charCodeAt(tokPos + 1);
    if (tokRegexpAllowed) {
      ++tokPos;
      readRegexp();
    } else if (next === 61) {
      finishOp(_assign, 2);
    } else {
      finishOp(_slash, 1);
    }
  }

  function readToken_mult_modulo() {  // '%*'
    var next = input.charCodeAt(tokPos + 1);
    if (next === 61) {
      finishOp(_assign, 2);
    } else {
      finishOp(_multiplyModulo, 1);
    }
  }

  /**
   * @param {number} code
   */
  function readToken_pipe_amp(code) {  // '|&'
    var next = input.charCodeAt(tokPos + 1);
    if (next === code) {
      finishOp(code === 124 ? _logicalOR : _logicalAND, 2);
    } else if (next === 61) {
      finishOp(_assign, 2);
    } else {
      finishOp(code === 124 ? _bitwiseOR : _bitwiseAND, 1);
    }
  }

  function readToken_caret() {  // '^'
    var next = input.charCodeAt(tokPos + 1);
    if (next === 61) {
      finishOp(_assign, 2);
    } else {
      finishOp(_bitwiseXOR, 1);
    }
  }

  /**
   * @param {number} code
   */
  function readToken_plus_min(code) {  // '+-'
    var next = input.charCodeAt(tokPos + 1);
    if (next === code) {
      if (next === 45 && input.charCodeAt(tokPos + 2) === 62 &&
          newline.test(input.slice(lastEnd, tokPos))) {
        // A `-->` line comment
        tokPos += 3;
        skipLineComment();
        skipSpace();
        readToken();
        return;
      }
      finishOp(_incDec, 2);
    } else if (next === 61) {
      finishOp(_assign, 2);
    } else {
      finishOp(_plusMin, 1);
    }
  }

  /**
   * @param {number} code
   */
  function readToken_lt_gt(code) {  // '<>'
    var next = input.charCodeAt(tokPos + 1);
    var size = 1;
    if (next === code) {
      size = (code === 62 && input.charCodeAt(tokPos + 2) === 62) ? 3 : 2;
      if (input.charCodeAt(tokPos + size) === 61) {
        finishOp(_assign, size + 1);
      } else {
        finishOp(_bitShift, size);
      }
      return;
    }
    if (next === 33 && code === 60 && input.charCodeAt(tokPos + 2) === 45 &&
        input.charCodeAt(tokPos + 3) === 45) {
      // `<!--`, an XML-style comment that should be interpreted as a line comment
      tokPos += 4;
      skipLineComment();
      skipSpace();
      readToken();
      return;
    }
    if (next === 61) {
      size = input.charCodeAt(tokPos + 2) === 61 ? 3 : 2;
    }
    finishOp(_relational, size);
  }

  /**
   * @param {number} code
   */
  function readToken_eq_excl(code) {  // '=!'
    var next = input.charCodeAt(tokPos + 1);
    if (next === 61) {
      finishOp(_equality, input.charCodeAt(tokPos + 2) === 61 ? 3 : 2);
    } else {
      finishOp(code === 61 ? _eq : _prefix, 1);
    }
  }

  /**
   * @param {number} code
   * @returns {boolean|undefined}
   */
  function getTokenFromCode(code) {
    switch(code) {
      // The interpretation of a dot depends on whether it is followed
      // by a digit.
      case 46: // '.'
        return readToken_dot();

        // Punctuation tokens.
      case 40:  ++tokPos; return finishToken(_parenL);
      case 41:  ++tokPos; return finishToken(_parenR);
      case 59:  ++tokPos; return finishToken(_semi);
      case 44:  ++tokPos; return finishToken(_comma);
      case 91:  ++tokPos; return finishToken(_bracketL);
      case 93:  ++tokPos; return finishToken(_bracketR);
      case 123: ++tokPos; return finishToken(_braceL);
      case 125: ++tokPos; return finishToken(_braceR);
      case 58:  ++tokPos; return finishToken(_colon);
      case 63:  ++tokPos; return finishToken(_question);

        // '0x' is a hexadecimal number.
      case 48: // '0'
        var next = input.charCodeAt(tokPos + 1);
        if (next === 120 || next === 88) return readHexNumber();
        // Anything else beginning with a digit is an integer, octal
        // number, or float.
      case 49: case 50: case 51: case 52: case 53: case 54: case 55: case 56: case 57: // 1-9
        return readNumber(false);

        // Quotes produce strings.
      case 34: case 39: // '"', "'"
        return readString(code);

      // Operators are parsed inline in tiny state machines. '=' (61) is
      // often referred to. `finishOp` simply skips the amount of
      // characters it is given as second argument, and returns a token
      // of the type given by its first argument.

      case 47: // '/'
        return readToken_slash();

      case 37: case 42: // '%*'
        return readToken_mult_modulo();

      case 124: case 38: // '|&'
        return readToken_pipe_amp(code);

      case 94: // '^'
        return readToken_caret();

      case 43: case 45: // '+-'
        return readToken_plus_min(code);

      case 60: case 62: // '<>'
        return readToken_lt_gt(code);

      case 61: case 33: // '=!'
        return readToken_eq_excl(code);

      case 126: // '~'
        return finishOp(_prefix, 1);
    }

    return false;
  }

  /**
   * @param {boolean=} forceRegexp
   */
  function readToken(forceRegexp) {
    if (!forceRegexp) {
      tokStart = tokPos;
    } else {
      tokPos = tokStart + 1;
    }
    if (options.locations) {
      tokStartLoc = new line_loc_t();
    }
    if (forceRegexp) return readRegexp();
    if (tokPos >= inputLen) return finishToken(_eof);

    var code = input.charCodeAt(tokPos);
    // Identifier or keyword. '\uXXXX' sequences are allowed in
    // identifiers, so '\' also dispatches to that.
    if (isIdentifierStart(code) || code === 92) {  // '\'
      return readWord();
    }

    var tok = getTokenFromCode(code);

    if (tok === false) {
      // If we are here, we either found a non-ASCII identifier
      // character, or something that's entirely disallowed.
      var ch = String.fromCharCode(code);
      if (ch === "\\" || nonASCIIidentifierStart.test(ch)) {
        return readWord();
      }
      raise(tokPos, "Unexpected character '" + ch + "'");
    }
  }

  /**
   * @param {!Object} type
   * @param {number} size
   */
  function finishOp(type, size) {
    var str = input.slice(tokPos, tokPos + size);
    tokPos += size;
    finishToken(type, str);
  }

  /**
   * Parse a regular expression. Some context-awareness is necessary,
   * since a '/' inside a '[]' set does not end the expression.
   */
  function readRegexp() {
    // JS-Interpreter change:
    // Removed redundant declaration of 'content' here.  Caused lint errors.
    // -- Neil Fraser, June 2022.
    var escaped;
    var inClass;
    var start = tokPos;
    for (;;) {
      if (tokPos >= inputLen) raise(start, "Unterminated regexp");
      var ch = input.charAt(tokPos);
      if (newline.test(ch)) raise(start, "Unterminated regexp");
      if (!escaped) {
        if (ch === "[") {
          inClass = true;
        } else if (ch === "]" && inClass) {
          inClass = false;
        } else if (ch === "/" && !inClass) {
          break;
        }
        escaped = ch === "\\";
      } else escaped = false;
      ++tokPos;
    }
    var content = input.slice(start, tokPos);
    ++tokPos;
    // Need to use `readWord1` because '\uXXXX' sequences are allowed
    // here (don't ask).
    var mods = readWord1();
    // JS-Interpreter change:
    // Acorn used to use 'gmsiy' to check for flags.  But 's' and 'y' are ES6.
    // -- Neil Fraser, December 2022.
    // https://github.com/acornjs/acorn/issues/1163
    if (mods && !/^[gmi]*$/.test(mods)) {
      raise(start, "Invalid regexp flag");
    }
    try {
      var value = new RegExp(content, mods);
    } catch (e) {
      if (e instanceof SyntaxError) raise(start, e.message);
      // JS-Interpreter change:
      // Acorn used to use raise(e) here which is incorrect.
      // -- Neil Fraser, July 2023.
      throw(e);
    }
    finishToken(_regexp, value);
  }

  /**
   * Read an integer in the given radix. Return null if zero digits
   * were read, the integer value otherwise. When `len` is given, this
   * will return `null` unless the integer has exactly `len` digits.
   * @param {number} radix
   * @param {number=} len
   * @returns {?number}
   */
  function readInt(radix, len) {
    var start = tokPos;
    var total = 0;
    var e = (len === undefined) ? Infinity : len;
    for (var i = 0; i < e; ++i) {
      var code = input.charCodeAt(tokPos), val;
      if (code >= 97) {
        val = code - 97 + 10; // a
      } else if (code >= 65) {
        val = code - 65 + 10; // A
      } else if (code >= 48 && code <= 57) {
        val = code - 48; // 0-9
      } else {
        val = Infinity;
      }
      if (val >= radix) break;
      ++tokPos;
      total = total * radix + val;
    }
    if (tokPos === start || len !== undefined && tokPos - start !== len) {
      return null;
    }
    return total;
  }

  function readHexNumber() {
    tokPos += 2; // 0x
    var val = readInt(16);
    if (val === null) {
      raise(tokStart + 2, "Expected hexadecimal number");
    }
    if (isIdentifierStart(input.charCodeAt(tokPos))) {
      raise(tokPos, "Identifier directly after number");
    }
    finishToken(_num, val);
  }

  /**
   * Read an integer, octal integer, or floating-point number.
   *
   * @param {boolean} startsWithDot
   */
  function readNumber(startsWithDot) {
    var start = tokPos;
    var isFloat = false;
    var octal = input.charCodeAt(tokPos) === 48;
    if (!startsWithDot && readInt(10) === null) {
      raise(start, "Invalid number");
    }
    if (input.charCodeAt(tokPos) === 46) {
      ++tokPos;
      readInt(10);
      isFloat = true;
    }
    var next = input.charCodeAt(tokPos);
    if (next === 69 || next === 101) { // 'eE'
      next = input.charCodeAt(++tokPos);
      if (next === 43 || next === 45) {
        ++tokPos; // '+-'
      }
      if (readInt(10) === null) {
        raise(start, "Invalid number");
      }
      isFloat = true;
    }
    if (isIdentifierStart(input.charCodeAt(tokPos))) {
      raise(tokPos, "Identifier directly after number");
    }

    var str = input.slice(start, tokPos);
    var val;
    if (isFloat) {
      val = parseFloat(str);
    } else if (!octal || str.length === 1) {
      val = parseInt(str, 10);
    } else if (/[89]/.test(str) || strict) {
      raise(start, "Invalid number");
    } else {
      val = parseInt(str, 8);
    }
    finishToken(_num, val);
  }

  /**
   * Read a string value, interpreting backslash-escapes.
   *
   * @param {number} quote
   */
  function readString(quote) {
    tokPos++;
    var out = "";
    for (;;) {
      if (tokPos >= inputLen) raise(tokStart, "Unterminated string constant");
      var ch = input.charCodeAt(tokPos);
      if (ch === quote) {
        ++tokPos;
        finishToken(_string, out);
        return;
      }
      if (ch === 92) { // '\'
        ch = input.charCodeAt(++tokPos);
        var octal = /^[0-7]+/.exec(input.slice(tokPos, tokPos + 3));
        if (octal) {
          octal = octal[0];
        }
        while (octal && parseInt(octal, 8) > 255) {
          octal = octal.slice(0, -1);
        }
        if (octal === "0") {
          octal = null;
        }
        ++tokPos;
        if (octal) {
          if (strict) raise(tokPos - 2, "Octal literal in strict mode");
          out += String.fromCharCode(parseInt(octal, 8));
          tokPos += octal.length - 1;
        } else {
          switch (ch) {
            case 110: out += "\n"; break; // 'n' -> '\n'
            case 114: out += "\r"; break; // 'r' -> '\r'
            case 120: out += String.fromCharCode(readHexChar(2)); break; // 'x'
            case 117: out += String.fromCharCode(readHexChar(4)); break; // 'u'
            case 85: out += String.fromCharCode(readHexChar(8)); break; // 'U'
            case 116: out += "\t"; break; // 't' -> '\t'
            case 98: out += "\b"; break; // 'b' -> '\b'
            case 118: out += "\u000b"; break; // 'v' -> '\u000b'
            case 102: out += "\f"; break; // 'f' -> '\f'
            case 48: out += "\0"; break; // 0 -> '\0'
            case 13:  // '\r'
              if (input.charCodeAt(tokPos) === 10) {
                ++tokPos; // '\r\n'
              }
            case 10: // ' \n'
              if (options.locations) {
                tokLineStart = tokPos;
                ++tokCurLine;
              }
              break;
            default: out += String.fromCharCode(ch); break;
          }
        }
      } else {
        if (ch === 13 || ch === 10 || ch === 8232 || ch === 8233) {
          raise(tokStart, "Unterminated string constant");
        }
        out += String.fromCharCode(ch); // '\'
        ++tokPos;
      }
    }
  }

  /**
   * Used to read character escape sequences ('\x', '\u', '\U').
   *
   * @param {number} len
   * @returns {number}
   */
  function readHexChar(len) {
    var n = readInt(16, len);
    if (n === null) raise(tokStart, "Bad character escape sequence");
    return /** @type {number} */(n);
  }

  // Used to signal to callers of `readWord1` whether the word
  // contained any escape sequences. This is needed because words with
  // escape sequences must not be interpreted as keywords.

  /** @type {boolean|undefined} */
  var containsEsc;

  /**
   * Read an identifier, and return it as a string. Sets `containsEsc`
   * to whether the word contained a '\u' escape.
   *
   * Only builds up the word character-by-character when it actually
   * containeds an escape, as a micro-optimization.
   *
   * @returns {string|undefined}
   */
  function readWord1() {
    containsEsc = false;
    var word;
    var first = true;
    var start = tokPos;
    for (;;) {
      var ch = input.charCodeAt(tokPos);
      if (isIdentifierChar(ch)) {
        if (containsEsc) {
          word += input.charAt(tokPos);
        }
        ++tokPos;
      } else if (ch === 92) { // "\"
        if (!containsEsc) {
          word = input.slice(start, tokPos);
        }
        containsEsc = true;
        if (input.charCodeAt(++tokPos) !== 117) { // "u"
          raise(tokPos, "Expecting Unicode escape sequence \\uXXXX");
        }
        ++tokPos;
        var esc = readHexChar(4);
        var escStr = String.fromCharCode(esc);
        if (!escStr) raise(tokPos - 1, "Invalid Unicode escape");
        if (!(first ? isIdentifierStart(esc) : isIdentifierChar(esc))) {
          raise(tokPos - 4, "Invalid Unicode escape");
        }
        word += escStr;
      } else {
        break;
      }
      first = false;
    }
    return containsEsc ? word : input.slice(start, tokPos);
  }

  /**
   * Read an identifier or keyword token. Will check for reserved
   * words when necessary.
   */
  function readWord() {
    var word = readWord1();
    var type = _name;
    if (!containsEsc && isKeyword(word)) {
      type = keywordTypes[word];
    }
    finishToken(type, word);
  }

  // ## Parser

  // A recursive descent parser operates by defining functions for all
  // syntactic elements, and recursively calling those, each function
  // advancing the input stream and returning an AST node. Precedence
  // of constructs (for example, the fact that `!x[1]` means `!(x[1])`
  // instead of `(!x)[1]` is handled by the fact that the parser
  // function that parses unary prefix operators is called first, and
  // in turn calls the function that parses `[]` subscripts — that
  // way, it'll receive the node for `x[1]` already parsed, and wraps
  // *that* in the unary operator node.
  //
  // Acorn uses an [operator precedence parser][opp] to handle binary
  // operator precedence, because it is much more compact than using
  // the technique outlined above, which uses different, nesting
  // functions to specify precedence, for all of the ten binary
  // precedence levels that JavaScript defines.
  //
  // [opp]: http://en.wikipedia.org/wiki/Operator-precedence_parser

  // ### Parser utilities

  /**
   * Continue to the next token.
   */
  function next() {
    lastStart = tokStart;
    lastEnd = tokEnd;
    lastEndLoc = tokEndLoc;
    readToken();
  }

  /**
   * Enter strict mode. Re-reads the next token to please pedantic
   * tests ("use strict"; 010; -- should fail).
   *
   * @param {boolean} strct
   */
  function setStrict(strct) {
    strict = strct;
    tokPos = tokStart;
    if (options.locations) {
      while (tokPos < tokLineStart) {
        tokLineStart = input.lastIndexOf("\n", tokLineStart - 2) + 1;
        --tokCurLine;
      }
    }
    skipSpace();
    readToken();
  }

  // Start an AST node, attaching a start offset.

  /**
   * @constructor
   */
  function node_t() {
    this.type = null;
    this.start = tokStart;
    this.end = null;
  }

  /**
   * @constructor
   */
  function node_loc_t() {
    this.start = tokStartLoc;
    this.end = null;
    if (sourceFile) {
      this.source = sourceFile;
    }
  }

  /**
   * @returns {!node_t}
   */
  function startNode() {
    var node = new node_t();
    if (options.locations) {
      node.loc = new node_loc_t();
    }
    if (options.directSourceFile) {
      node.sourceFile = options.directSourceFile;
    }
    if (options.ranges) {
      node.range = [tokStart, 0];
    }
    return node;
  }

  /**
   * Start a node whose start offset information should be based on
   * the start of another node. For example, a binary operator node is
   * only started after its left-hand side has already been parsed.
   *
   * @param {!node_t} other
   * @returns {!node_t}
   */
  function startNodeFrom(other) {
    var node = new node_t();
    node.start = other.start;
    if (options.locations) {
      node.loc = new node_loc_t();
      node.loc.start = other.loc.start;
    }
    if (options.ranges) {
      node.range = [other.range[0], 0];
    }
    return node;
  }

  /**
   * Finish an AST node, adding `type` and `end` properties.
   *
   * @param {!node_t} node
   * @param {string} type
   * @returns {!node_t}
   */
  function finishNode(node, type) {
    node.type = type;
    node.end = lastEnd;
    if (options.locations) {
      node.loc.end = lastEndLoc;
    }
    if (options.ranges) {
      node.range[1] = lastEnd;
    }
    return node;
  }

  /**
   * Test whether a statement node is the string literal `"use strict"`.
   *
   * @param {!node_t} stmt
   * @returns {boolean}
   */
  function isUseStrict(stmt) {
    return stmt.type === "ExpressionStatement" &&
        stmt.expression.type === "Literal" &&
        stmt.expression.value === "use strict";
  }

  /**
   * Predicate that tests whether the next token is of the given
   * type, and if yes, consumes it as a side effect.
   * @param {!Object} type
   * @returns {boolean}
   */
  function eat(type) {
    if (tokType === type) {
      next();
      return true;
    }
    return false;
  }

  /**
   * Test whether a semicolon can be inserted at the current position.
   *
   * @returns {boolean}
   */
  function canInsertSemicolon() {
    return !options.strictSemicolons &&
        (tokType === _eof || tokType === _braceR ||
         newline.test(input.slice(lastEnd, tokStart)));
  }

  /**
   * Consume a semicolon, or, failing that, see if we are allowed to
   * pretend that there is a semicolon at this position.
   */
  function semicolon() {
    if (!eat(_semi) && !canInsertSemicolon()) {
      unexpected();
    }
  }

  /**
   * Expect a token of a given type.  If found, consume it, otherwise,
   * raise an unexpected token error.
   *
   * @param {!Object} type
   */
  function expect(type) {
    if (tokType === type) {
      next();
    } else {
      unexpected();
    }
  }

  /**
   * Raise an unexpected token error.
   * @throws {SyntaxError}
   */
  function unexpected() {
    raise(tokStart, "Unexpected token");
  }

  /**
   * Verify that a node is an lval — something that can be assigned to.
   *
   * @param {!node_t} expr
   */
  function checkLVal(expr) {
    if (expr.type !== "Identifier" && expr.type !== "MemberExpression") {
      raise(expr.start, "Assigning to rvalue");
    }
    if (strict && expr.type === "Identifier" && isStrictBadIdWord(expr.name)) {
      raise(expr.start, "Assigning to " + expr.name + " in strict mode");
    }
  }

  // ### Statement parsing

  /**
   * Parse a program. Initializes the parser, reads any number of
   * statements, and wraps them in a Program node.  Optionally takes a
   * `program` argument.  If present, the statements will be appended
   * to its body instead of creating a new node.
   *
   * @param {node_t} program
   * @returns {!node_t}
   */
  function parseTopLevel(program) {
    lastStart = lastEnd = tokPos;
    if (options.locations) {
      lastEndLoc = new line_loc_t();
    }
    inFunction = strict = false;
    labels = [];
    readToken();

    var node = program || startNode();
    var first = true;
    if (!program) {
      node.body = [];
    }
    while (tokType !== _eof) {
      var stmt = parseStatement();
      node.body.push(stmt);
      if (first && isUseStrict(stmt)) {
        setStrict(true);
      }
      first = false;
    }
    return finishNode(node, "Program");
  }

  var loopLabel = {kind: "loop"};
  var switchLabel = {kind: "switch"};

  /**
   * Parse a single statement.
   *
   * If expecting a statement and finding a slash operator, parse a
   * regular expression literal. This is to handle cases like
   * `if (foo) /blah/.exec(foo);`, where looking at the previous token
   * does not help.
   *
   * @returns {!node_t}
   */
  function parseStatement() {
    if (tokType === _slash || tokType === _assign && tokVal === "/=") {
      readToken(true);
    }

    var starttype = tokType;
    var node = startNode();

    // Most types of statements are recognized by the keyword they
    // start with. Many are trivial to parse, some require a bit of
    // complexity.

    switch (starttype) {
      case _break: case _continue:
        next();
        var isBreak = starttype === _break;
        if (eat(_semi) || canInsertSemicolon()) {
          node.label = null;
        } else if (tokType !== _name) {
          unexpected();
        } else {
          node.label = parseIdent();
          semicolon();
        }

        // Verify that there is an actual destination to break or
        // continue to.
        for (var i = 0; i < labels.length; ++i) {
          var lab = labels[i];
          if (node.label === null || lab.name === node.label.name) {
            if (lab.kind !== null && (isBreak || lab.kind === "loop")) break;
            if (node.label && isBreak) break;
          }
        }
        if (i === labels.length) {
          raise(node.start, "Unsyntactic " + starttype.keyword);
        }
        return finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement");

      case _debugger:
        next();
        semicolon();
        return finishNode(node, "DebuggerStatement");

      case _do:
        next();
        labels.push(loopLabel);
        node.body = parseStatement();
        labels.pop();
        expect(_while);
        node.test = parseParenExpression();
        semicolon();
        return finishNode(node, "DoWhileStatement");

        // Disambiguating between a `for` and a `for`/`in` loop is
        // non-trivial. Basically, we have to parse the init `var`
        // statement or expression, disallowing the `in` operator (see
        // the second parameter to `parseExpression`), and then check
        // whether the next token is `in`. When there is no init part
        // (semicolon immediately after the opening parenthesis), it is
        // a regular `for` loop.

      case _for:
        next();
        labels.push(loopLabel);
        expect(_parenL);
        if (tokType === _semi) return parseFor(node, null);
        if (tokType === _var) {
          var init = startNode();
          next();
          parseVar(init, true);
          finishNode(init, "VariableDeclaration");
          if (init.declarations.length === 1 && eat(_in))
            return parseForIn(node, init);
          return parseFor(node, init);
        }
        var init = parseExpression(false, true);
        if (eat(_in)) {
          checkLVal(init);
          return parseForIn(node, init);
        }
        return parseFor(node, init);

      case _function:
        next();
        return parseFunction(node, true);

      case _if:
        next();
        node.test = parseParenExpression();
        node.consequent = parseStatement();
        node.alternate = eat(_else) ? parseStatement() : null;
        return finishNode(node, "IfStatement");

      case _return:
        if (!inFunction && !options.allowReturnOutsideFunction) {
          raise(tokStart, "'return' outside of function");
        }
        next();

        // In `return` (and `break`/`continue`), the keywords with
        // optional arguments, we eagerly look for a semicolon or the
        // possibility to insert one.

        if (eat(_semi) || canInsertSemicolon()) {
          node.argument = null;
        } else {
          node.argument = parseExpression();
          semicolon();
        }
        return finishNode(node, "ReturnStatement");

      case _switch:
        next();
        node.discriminant = parseParenExpression();
        node.cases = [];
        expect(_braceL);
        labels.push(switchLabel);

        // Statements under must be grouped (by label) in SwitchCase
        // nodes. `cur` is used to keep the node that we are currently
        // adding statements to.

        for (var cur, sawDefault; tokType !== _braceR;) {
          if (tokType === _case || tokType === _default) {
            var isCase = tokType === _case;
            if (cur) {
              finishNode(cur, "SwitchCase");
            }
            node.cases.push(cur = startNode());
            cur.consequent = [];
            next();
            if (isCase) {
              cur.test = parseExpression();
            } else {
              if (sawDefault) {
                raise(lastStart, "Multiple default clauses");
              }
              sawDefault = true;
              cur.test = null;
            }
            expect(_colon);
          } else {
            if (!cur) unexpected();
            cur.consequent.push(parseStatement());
          }
        }
        if (cur) finishNode(cur, "SwitchCase");
        next(); // Closing brace
        labels.pop();
        return finishNode(node, "SwitchStatement");

      case _throw:
        next();
        if (newline.test(input.slice(lastEnd, tokStart)))
          raise(lastEnd, "Illegal newline after throw");
        node.argument = parseExpression();
        semicolon();
        return finishNode(node, "ThrowStatement");

      case _try:
        next();
        node.block = parseBlock();
        node.handler = null;
        if (tokType === _catch) {
          var clause = startNode();
          next();
          expect(_parenL);
          clause.param = parseIdent();
          if (strict && isStrictBadIdWord(clause.param.name))
            raise(clause.param.start, "Binding " + clause.param.name + " in strict mode");
          expect(_parenR);
          // JS-Interpreter change:
          // Obsolete unused property; commenting out.
          // -- Neil Fraser, January 2023.
          // clause.guard = null;
          clause.body = parseBlock();
          node.handler = finishNode(clause, "CatchClause");
        }
        // JS-Interpreter change:
        // Obsolete unused property; commenting out.
        // -- Neil Fraser, January 2023.
        // node.guardedHandlers = empty;
        node.finalizer = eat(_finally) ? parseBlock() : null;
        if (!node.handler && !node.finalizer)
          raise(node.start, "Missing catch or finally clause");
        return finishNode(node, "TryStatement");

      case _var:
        next();
        parseVar(node);
        semicolon();
        return finishNode(node, "VariableDeclaration");

      case _while:
        next();
        node.test = parseParenExpression();
        labels.push(loopLabel);
        node.body = parseStatement();
        labels.pop();
        return finishNode(node, "WhileStatement");

      case _with:
        if (strict) raise(tokStart, "'with' in strict mode");
        next();
        node.object = parseParenExpression();
        node.body = parseStatement();
        return finishNode(node, "WithStatement");

      case _braceL:
        return parseBlock();

      case _semi:
        next();
        return finishNode(node, "EmptyStatement");

      // If the statement does not start with a statement keyword or a
      // brace, it's an ExpressionStatement or LabeledStatement. We
      // simply start parsing an expression, and afterwards, if the
      // next token is a colon and the expression was a simple
      // Identifier node, we switch to interpreting it as a label.
      default:
        var maybeName = tokVal;
        var expr = parseExpression();
        if (starttype === _name && expr.type === "Identifier" && eat(_colon)) {
          for (var i = 0; i < labels.length; ++i) {
            if (labels[i].name === maybeName) {
              raise(expr.start, "Label '" + maybeName + "' is already declared");
            }
          }
          var kind = tokType.isLoop ? "loop" :
              (tokType === _switch ? "switch" : null);
          labels.push({name: maybeName, kind: kind});
          node.body = parseStatement();
          labels.pop();
          node.label = expr;
          return finishNode(node, "LabeledStatement");
        } else {
          node.expression = expr;
          semicolon();
          return finishNode(node, "ExpressionStatement");
        }
    }
  }

  /**
   * Used for constructs like `switch` and `if` that insist on
   * parentheses around their expression.
   *
   * @returns {!node_t}
   */
  function parseParenExpression() {
    expect(_parenL);
    var val = parseExpression();
    expect(_parenR);
    return val;
  }

  /**
   * Parse a semicolon-enclosed block of statements, handling `"use
   * strict"` declarations when `allowStrict` is true (used for
   * function bodies).
   *
   * @param {boolean=} allowStrict
   * @returns {!node_t}
   */
  function parseBlock(allowStrict) {
    var node = startNode();
    var first = true;
    var strict = false;
    var oldStrict;
    node.body = [];
    expect(_braceL);
    while (!eat(_braceR)) {
      var stmt = parseStatement();
      node.body.push(stmt);
      if (first && allowStrict && isUseStrict(stmt)) {
        oldStrict = strict;
        setStrict(strict = true);
      }
      first = false;
    }
    if (strict && !oldStrict) setStrict(false);
    return finishNode(node, "BlockStatement");
  }

  /**
   * Parse a regular `for` loop. The disambiguation code in `parseStatement`
   * will already have parsed the init statement or expression.
   *
   * @param {!node_t} node
   * @param {node_t} init
   * @returns {!node_t}
   */
  function parseFor(node, init) {
    node.init = init;
    expect(_semi);
    node.test = tokType === _semi ? null : parseExpression();
    expect(_semi);
    node.update = tokType === _parenR ? null : parseExpression();
    expect(_parenR);
    node.body = parseStatement();
    labels.pop();
    return finishNode(node, "ForStatement");
  }

  /**
   * Parse a `for`/`in` loop.
   *
   * @param {!node_t} node
   * @param {!node_t} init
   * @returns {!node_t}
   */
  function parseForIn(node, init) {
    node.left = init;
    node.right = parseExpression();
    expect(_parenR);
    node.body = parseStatement();
    labels.pop();
    return finishNode(node, "ForInStatement");
  }

  /**
   * Parse a list of variable declarations.
   *
   * @param {!node_t} node
   * @param {boolean=} noIn
   */
  function parseVar(node, noIn) {
    node.declarations = [];
    node.kind = "var";
    for (;;) {
      var decl = startNode();
      decl.id = parseIdent();
      if (strict && isStrictBadIdWord(decl.id.name))
        raise(decl.id.start, "Binding " + decl.id.name + " in strict mode");
      decl.init = eat(_eq) ? parseExpression(true, noIn) : null;
      node.declarations.push(finishNode(decl, "VariableDeclarator"));
      if (!eat(_comma)) break;
    }
  }

  // ### Expression parsing

  // These nest, from the most general expression type at the top to
  // 'atomic', nondivisible expression types at the bottom. Most of
  // the functions will simply let the function(s) below them parse,
  // and, *if* the syntactic construct they handle is present, wrap
  // the AST node that the inner parser gave them in another node.

  /**
   * Parse a full expression. The arguments are used to forbid comma
   * sequences (in argument lists, array literals, or object literals)
   * or the `in` operator (in for loops initalization expressions).
   *
   * @param {boolean=} noComma
   * @param {boolean=} noIn
   * @returns {!node_t}
   */
  function parseExpression(noComma, noIn) {
    var expr = parseMaybeAssign(noIn);
    if (!noComma && tokType === _comma) {
      var node = startNodeFrom(expr);
      node.expressions = [expr];
      while (eat(_comma)) node.expressions.push(parseMaybeAssign(noIn));
      return finishNode(node, "SequenceExpression");
    }
    return expr;
  }

  /**
   * Parse an assignment expression. This includes applications of
   * operators like `+=`.
   *
   * @param {boolean|undefined} noIn
   * @returns {!node_t}
   */
  function parseMaybeAssign(noIn) {
    var left = parseMaybeConditional(noIn);
    if (tokType.isAssign) {
      var node = startNodeFrom(left);
      node.operator = tokVal;
      node.left = left;
      next();
      node.right = parseMaybeAssign(noIn);
      checkLVal(left);
      return finishNode(node, "AssignmentExpression");
    }
    return left;
  }

  /**
   * Parse a ternary conditional (`?:`) operator.
   *
   * @param {boolean|undefined} noIn
   * @returns {!node_t}
   */
  function parseMaybeConditional(noIn) {
    var expr = parseExprOps(noIn);
    if (eat(_question)) {
      var node = startNodeFrom(expr);
      node.test = expr;
      node.consequent = parseExpression(true);
      expect(_colon);
      node.alternate = parseExpression(true, noIn);
      return finishNode(node, "ConditionalExpression");
    }
    return expr;
  }

  /**
   * Start the precedence parser.
   *
   * @param {boolean|undefined} noIn
   * @returns {!node_t}
   */
  function parseExprOps(noIn) {
    return parseExprOp(parseMaybeUnary(), -1, noIn);
  }

  /**
   * Parse binary operators with the operator precedence parsing
   * algorithm. `left` is the left-hand side of the operator.
   * `minPrec` provides context that allows the function to stop and
   * defer further parser to one of its callers when it encounters an
   * operator that has a lower precedence than the set it is parsing.
   *
   * @param {!node_t} left
   * @param {number} minPrec
   * @param {boolean|undefined} noIn
   * @returns {!node_t}
   */
  function parseExprOp(left, minPrec, noIn) {
    var prec = tokType.binop;
    if (prec !== null && (!noIn || tokType !== _in)) {
      if (prec > minPrec) {
        var node = startNodeFrom(left);
        node.left = left;
        node.operator = tokVal;
        var op = tokType;
        next();
        node.right = parseExprOp(parseMaybeUnary(), prec, noIn);
        var exprNode = finishNode(node, (op === _logicalOR || op === _logicalAND) ? "LogicalExpression" : "BinaryExpression");
        return parseExprOp(exprNode, minPrec, noIn);
      }
    }
    return left;
  }

  /**
   * Parse unary operators, both prefix and postfix.
   *
   * @returns {!node_t}
   */
  function parseMaybeUnary() {
    if (tokType.prefix) {
      var node = startNode();
      var update = tokType.isUpdate;
      node.operator = tokVal;
      node.prefix = true;
      tokRegexpAllowed = true;
      next();
      node.argument = parseMaybeUnary();
      if (update) checkLVal(node.argument);
      else if (strict && node.operator === "delete" &&
               node.argument.type === "Identifier")
        raise(node.start, "Deleting local variable in strict mode");
      return finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
    }
    var expr = parseExprSubscripts();
    while (tokType.postfix && !canInsertSemicolon()) {
      var node = startNodeFrom(expr);
      node.operator = tokVal;
      node.prefix = false;
      node.argument = expr;
      checkLVal(expr);
      next();
      expr = finishNode(node, "UpdateExpression");
    }
    return expr;
  }

  /**
   * Parse call, dot, and `[]`-subscript expressions.
   *
   * @returns {!node_t}
   */
  function parseExprSubscripts() {
    return parseSubscripts(parseExprAtom());
  }

  /**
   * @param {!node_t} base
   * @param {boolean=} noCalls
   * @returns {!node_t}
   */
  function parseSubscripts(base, noCalls) {
    var node;
    if (eat(_dot)) {
      node = startNodeFrom(base);
      node.object = base;
      node.property = parseIdent(true);
      node.computed = false;
      return parseSubscripts(finishNode(node, "MemberExpression"), noCalls);
    }
    if (eat(_bracketL)) {
      node = startNodeFrom(base);
      node.object = base;
      node.property = parseExpression();
      node.computed = true;
      expect(_bracketR);
      return parseSubscripts(finishNode(node, "MemberExpression"), noCalls);
    }
    if (!noCalls && eat(_parenL)) {
      node = startNodeFrom(base);
      node.callee = base;
      node.arguments = parseExprList(_parenR, false);
      return parseSubscripts(finishNode(node, "CallExpression"), noCalls);
    }
    return base;
  }

  /**
   * Parse an atomic expression — either a single token that is an expression,
   * an expression started by a keyword like `function` or `new`,
   * or an expression wrapped in punctuation like `()`, `[]`, or `{}`.
   *
   * @returns {!node_t}
   * @suppress {missingReturn}
   */
  function parseExprAtom() {
    var node;
    switch (tokType) {
      case _this:
        node = startNode();
        next();
        return finishNode(node, "ThisExpression");
      case _name:
        return parseIdent();
      case _num: case _string: case _regexp:
        node = startNode();
        node.value = tokVal;
        node.raw = input.slice(tokStart, tokEnd);
        next();
        return finishNode(node, "Literal");

      case _null: case _true: case _false:
        node = startNode();
        node.value = tokType.atomValue;
        node.raw = tokType.keyword;
        next();
        return finishNode(node, "Literal");

      case _parenL:
        var tokStartLoc1 = tokStartLoc;
        var tokStart1 = tokStart;
        next();
        var val = parseExpression();
        val.start = tokStart1;
        val.end = tokEnd;
        if (options.locations) {
          val.loc.start = tokStartLoc1;
          val.loc.end = tokEndLoc;
        }
        if (options.ranges) {
          val.range = [tokStart1, tokEnd];
        }
        expect(_parenR);
        return val;

      case _bracketL:
        node = startNode();
        next();
        node.elements = parseExprList(_bracketR, true, true);
        return finishNode(node, "ArrayExpression");

      case _braceL:
        return parseObj();

      case _function:
        node = startNode();
        next();
        return parseFunction(node, false);

      case _new:
        return parseNew();
    }
    unexpected();
  }

  /**
   * New's precedence is slightly tricky. It must allow its argument to be
   * a `[]` or dot subscript expression, but not a call — at least, not
   * without wrapping it in parentheses. Thus, it uses the noCalls argument
   * to parseSubscripts to prevent it from consuming the argument list.
   *
   * @returns {!node_t}
   */
  function parseNew() {
    var node = startNode();
    next();
    node.callee = parseSubscripts(parseExprAtom(), true);
    node.arguments = eat(_parenL) ? parseExprList(_parenR, false) : empty;
    return finishNode(node, "NewExpression");
  }

  /**
   * Parse an object literal.
   *
   * @returns {!node_t}
   */
  function parseObj() {
    var node = startNode();
    var first = true;
    var sawGetSet = false;
    node.properties = [];
    next();
    while (!eat(_braceR)) {
      if (!first) {
        expect(_comma);
        if (options.allowTrailingCommas && eat(_braceR)) {
          break;
        }
      } else {
        first = false;
      }

      var prop = {key: parsePropertyName()};
      var isGetSet = false;
      var kind;
      if (eat(_colon)) {
        prop.value = parseExpression(true);
        kind = prop.kind = "init";
      } else if (prop.key.type === "Identifier" &&
                 (prop.key.name === "get" || prop.key.name === "set")) {
        isGetSet = sawGetSet = true;
        kind = prop.kind = prop.key.name;
        prop.key = parsePropertyName();
        if (tokType !== _parenL) unexpected();
        prop.value = parseFunction(startNode(), false);
      } else {
        unexpected();
      }

      // getters and setters are not allowed to clash — either with
      // each other or with an init property — and in strict mode,
      // init properties are also not allowed to be repeated.

      if (prop.key.type === "Identifier" && (strict || sawGetSet)) {
        for (var i = 0; i < node.properties.length; ++i) {
          var other = node.properties[i];
          if (other.key.name === prop.key.name) {
            var conflict = kind === other.kind || isGetSet && other.kind === "init" ||
                kind === "init" && (other.kind === "get" || other.kind === "set");
            if (conflict && !strict && kind === "init" && other.kind === "init") {
              conflict = false;
            }
            if (conflict) {
              raise(prop.key.start, "Redefinition of property");
            }
          }
        }
      }
      node.properties.push(prop);
    }
    return finishNode(node, "ObjectExpression");
  }

  /**
   * @returns {!node_t}
   */
  function parsePropertyName() {
    if (tokType === _num || tokType === _string) {
      return parseExprAtom();
    }
    return parseIdent(true);
  }

  /**
   * Parse a function declaration or literal (depending on the
   * `isStatement` parameter).
   *
   * @param {!node_t} node
   * @param {boolean} isStatement
   * @returns {!node_t}
   */
  function parseFunction(node, isStatement) {
    if (tokType === _name) {
      node.id = parseIdent();
    } else if (isStatement) {
      unexpected();
    } else {
      node.id = null;
    }
    node.params = [];
    var first = true;
    expect(_parenL);
    while (!eat(_parenR)) {
      if (!first) {
        expect(_comma);
      } else {
        first = false;
      }
      node.params.push(parseIdent());
    }

    // Start a new scope with regard to labels and the `inFunction`
    // flag (restore them to their old value afterwards).
    var oldInFunc = inFunction;
    var oldLabels = labels;
    inFunction = true;
    labels = [];
    node.body = parseBlock(true);
    inFunction = oldInFunc;
    labels = oldLabels;

    // If this is a strict mode function, verify that argument names
    // are not repeated, and it does not try to bind the words `eval`
    // or `arguments`.
    if (strict || node.body.body.length && isUseStrict(node.body.body[0])) {
      for (var i = node.id ? -1 : 0; i < node.params.length; ++i) {
        var id = i < 0 ? node.id : node.params[i];
        if (isStrictReservedWord(id.name) || isStrictBadIdWord(id.name)) {
          raise(id.start, "Defining '" + id.name + "' in strict mode");
        }
        if (i >= 0) {
          for (var j = 0; j < i; ++j) {
            if (id.name === node.params[j].name) {
              raise(id.start, "Argument name clash in strict mode");
            }
          }
        }
      }
    }

    return finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression");
  }

  /**
   * Parses a comma-separated list of expressions, and returns them as
   * an array. `close` is the token type that ends the list, and
   * `allowEmpty` can be turned on to allow subsequent commas with
   * nothing in between them to be parsed as `null` (which is needed
   * for array literals).
   *
   * @param {!Object} close
   * @param {boolean} allowTrailingComma
   * @param {boolean=} allowEmpty
   * @returns {!Array<!node_t>}
   */
  function parseExprList(close, allowTrailingComma, allowEmpty) {
    var elts = [];
    var first = true;
    while (!eat(close)) {
      if (!first) {
        expect(_comma);
        if (allowTrailingComma && options.allowTrailingCommas && eat(close)) {
          break;
        }
      } else {
        first = false;
      }

      elts.push((allowEmpty && tokType === _comma) ?
          null : parseExpression(true));
    }
    return elts;
  }

  /**
   * Parse the next token as an identifier. If `liberal` is true (used
   * when parsing properties), it will also convert keywords into
   * identifiers.
   *
   * @param {boolean=} liberal
   * @returns {!node_t}
   */
  function parseIdent(liberal) {
    var node = startNode();
    if (liberal && options.forbidReserved === "everywhere") {
      liberal = false;
    }
    if (tokType === _name) {
      if (!liberal &&
          (options.forbidReserved && isReservedWord5(tokVal) ||
           strict && isStrictReservedWord(tokVal)) &&
          input.slice(tokStart, tokEnd).indexOf("\\") === -1) {
        raise(tokStart, "The keyword '" + tokVal + "' is reserved");
      }
      node.name = tokVal;
    } else if (liberal && tokType.keyword) {
      node.name = tokType.keyword;
    } else {
      unexpected();
    }
    tokRegexpAllowed = false;
    next();
    return finishNode(node, "Identifier");
  }

});