From 980845994016f67f7c4b4ac606355477e487d441 Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijnh@gmail.com>
Date: Thu, 19 Mar 2015 15:40:12 +0100
Subject: [PATCH] Start on ES6 port

---
 src/index.js     | 2743 ++++++++++++++++++++++++++++++++++++++++++++++
 src/tokentype.js |  142 +++
 src/util.js      |    9 +
 3 files changed, 2894 insertions(+)
 create mode 100644 src/index.js
 create mode 100644 src/tokentype.js
 create mode 100644 src/util.js

diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000000..cdb1db1a7f
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,2743 @@
+// Acorn is a tiny, fast JavaScript parser written in JavaScript.
+//
+// Acorn was written by Marijn Haverbeke, Ingvar Stepanyan, and
+// various contributors and released under an MIT license.
+//
+// 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
+
+import {has, isArray} from "./util"
+import {types as tt, keywords as keywordTypes} from "./tokentype"
+
+export const version = "0.12.1"
+
+// 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].
+//
+// [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API
+
+export function parse(input, options) {
+  let p = parser(options, input)
+  let startPos = p.options.locations ? [p.pos, p.curPosition()] : p.pos
+  p.nextToken()
+  return p.parseTopLevel(p.options.program || p.startNodeAt(startPos))
+}
+
+// A second optional argument can be given to further configure
+// the parser process. These options are recognized:
+
+export const defaultOptions = {
+  // `ecmaVersion` indicates the ECMAScript version to parse. Must
+  // be either 3, or 5, or 6. This influences support for strict
+  // mode, the set of reserved words, support for getters and
+  // setters and other features.
+  ecmaVersion: 5,
+  // Source type ("script" or "module") for different semantics
+  sourceType: "script",
+  // `onInsertedSemicolon` can be a callback that will be called
+  // when a semicolon is automatically inserted. It will be passed
+  // th position of the comma as an offset, and if `locations` is
+  // enabled, it is given the location as a `{line, column}` object
+  // as second argument.
+  onInsertedSemicolon: null,
+  // `onTrailingComma` is similar to `onInsertedSemicolon`, but for
+  // trailing commas.
+  onTrailingComma: null,
+  // By default, reserved words are not enforced. Disable
+  // `allowReserved` to enforce them. When this option has the
+  // value "never", reserved words and keywords can also not be
+  // used as property names.
+  allowReserved: true,
+  // When enabled, a return at the top level is not considered an
+  // error.
+  allowReturnOutsideFunction: false,
+  // When enabled, import/export statements are not constrained to
+  // appearing at the top of the program.
+  allowImportExportEverywhere: false,
+  // When enabled, hashbang directive in the beginning of file
+  // is allowed and treated as a line comment.
+  allowHashBang: 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 `onToken` option, which will
+  // cause Acorn to call that function with object in the same
+  // format as tokenize() returns. Note that you are not
+  // allowed to call the parser from the callback—that will
+  // corrupt its internal state.
+  onToken: null,
+  // 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,
+  // When enabled, parenthesized expressions are represented by
+  // (non-standard) ParenthesizedExpression nodes
+  preserveParens: false,
+  plugins: {}
+}
+
+// Registered plugins
+
+export const plugins = {}
+
+// Interpret and default an options object
+
+function getOptions(opts) {
+  let options = {}
+  for (let opt in defaultOptions)
+    options[opt] = opts && has(opts, opt) ? opts[opt] : defaultOptions[opt]
+
+  if (isArray(options.onToken)) {
+    var tokens = options.onToken;
+    options.onToken = (token) => tokens.push(token)
+  }
+  if (isArray(options.onComment))
+    options.onComment = pushComment(options, options.onComment);
+
+  return options;
+}
+
+function pushComment(options, array) {
+  return function (block, text, start, end, startLoc, endLoc) {
+    let comment = {
+      type: block ? 'Block' : 'Line',
+      value: text,
+      start: start,
+      end: end
+    }
+    if (options.locations)
+      comment.loc = new SourceLocation(this, startLoc, endLoc)
+    if (options.ranges)
+      comment.range = [start, end]
+    array.push(comment)
+  }
+}
+
+function parser(options, input) {
+  return new Parser(getOptions(options), String(input))
+}
+
+// This function tries to parse a single expression at a given
+// offset in a string. Useful for parsing mixed-language formats
+// that embed JavaScript expressions.
+
+export function parseExpressionAt(input, pos, options) {
+  let p = parser(options, input, pos)
+  p.nextToken()
+  return p.parseExpression()
+}
+
+// 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.
+
+export function getLineInfo(input, offset) {
+  for (let line = 1, cur = 0;;) {
+    lineBreak.lastIndex = cur
+    let match = lineBreak.exec(input)
+    if (match && match.index < offset) {
+      ++line
+      cur = match.index + match[0].length
+    } else {
+      return new Position(line, offset - cur)
+    }
+  }
+}
+
+// Acorn is organized as a tokenizer and a recursive-descent parser.
+// The `tokenize` export provides an interface to the tokenizer.
+// Because the tokenizer is optimized for being efficiently used by
+// the Acorn parser itself, this interface is somewhat crude and not
+// very modular.
+
+export function tokenizer(input, options) {
+  return parser(options, input)
+}
+
+// Object type used to represent tokens. Note that normally, tokens
+// simply exist as properties on the parser object. This is only
+// used for the onToken callback and the external tokenizer.
+
+class Token {
+  constructor(p) {
+    this.type = p.type;
+    this.value = p.value;
+    this.start = p.start;
+    this.end = p.end;
+    if (p.options.locations)
+      this.loc = new SourceLocation(p, p.startLoc, p.endLoc);
+    if (p.options.ranges)
+      this.range = [p.start, p.end];
+  }
+}
+
+// This is a trick taken from Esprima. It turns out that, on
+// non-Chrome browsers, to check whether a string is in a set, a
+// predicate containing a big ugly `switch` statement is faster than
+// a regular expression, and on Chrome the two are about on par.
+// This function uses `eval` (non-lexical) to produce such a
+// predicate from a space-separated string of words.
+//
+// It starts by sorting the words by length.
+
+function makePredicate(words) {
+  words = words.split(" ");
+  var f = "", cats = [];
+  out: for (var i = 0; i < words.length; ++i) {
+    for (var j = 0; j < cats.length; ++j)
+      if (cats[j][0].length == words[i].length) {
+        cats[j].push(words[i]);
+        continue out;
+      }
+    cats.push([words[i]]);
+  }
+  function compareTo(arr) {
+    if (arr.length == 1) return f += "return str === " + JSON.stringify(arr[0]) + ";";
+    f += "switch(str){";
+    for (var i = 0; i < arr.length; ++i) f += "case " + JSON.stringify(arr[i]) + ":";
+    f += "return true}return false;";
+  }
+
+  // When there are more than three length categories, an outer
+  // switch first dispatches on the lengths, to save on comparisons.
+
+  if (cats.length > 3) {
+    cats.sort(function(a, b) {return b.length - a.length;});
+    f += "switch(str.length){";
+    for (var i = 0; i < cats.length; ++i) {
+      var cat = cats[i];
+      f += "case " + cat[0].length + ":";
+      compareTo(cat);
+    }
+    f += "}";
+
+    // Otherwise, simply generate a flat `switch` statement.
+
+  } else {
+    compareTo(words);
+  }
+  return new Function("str", f);
+}
+
+// The ECMAScript 3 reserved word list.
+
+var isReservedWord3 = makePredicate("abstract boolean byte char class double enum export extends final float goto implements import int interface long native package private protected public short static super synchronized throws transient volatile");
+
+// ECMAScript 5 reserved words.
+
+var isReservedWord5 = makePredicate("class enum extends super const export import");
+
+// ECMAScript 6 reserved words.
+
+var isReservedWord6 = makePredicate("enum await");
+
+// 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 ecma5AndLessKeywords = "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";
+
+var isEcma5AndLessKeyword = makePredicate(ecma5AndLessKeywords);
+
+var isEcma6Keyword = makePredicate(ecma5AndLessKeywords + " let const class extends export import yield super");
+
+// ## 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.
+// Generated by `tools/generate-identifier-regex.js`.
+
+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\u037f\u0386\u0388-\u038a\u038c\u038e-\u03a1\u03a3-\u03f5\u03f7-\u0481\u048a-\u052f\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-\u08b2\u0904-\u0939\u093d\u0950\u0958-\u0961\u0971-\u0980\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-\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-\u16f8\u1700-\u170c\u170e-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176c\u176e-\u1770\u1780-\u17b3\u17d7\u17dc\u1820-\u1877\u1880-\u18a8\u18aa\u18b0-\u18f5\u1900-\u191e\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\u2118-\u211d\u2124\u2126\u2128\u212a-\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\u3005-\u3007\u3021-\u3029\u3031-\u3035\u3038-\u303c\u3041-\u3096\u309b-\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-\ua69d\ua6a0-\ua6ef\ua717-\ua71f\ua722-\ua788\ua78b-\ua78e\ua790-\ua7ad\ua7b0\ua7b1\ua7f7-\ua801\ua803-\ua805\ua807-\ua80a\ua80c-\ua822\ua840-\ua873\ua882-\ua8b3\ua8f2-\ua8f7\ua8fb\ua90a-\ua925\ua930-\ua946\ua960-\ua97c\ua984-\ua9b2\ua9cf\ua9e0-\ua9e4\ua9e6-\ua9ef\ua9fa-\ua9fe\uaa00-\uaa28\uaa40-\uaa42\uaa44-\uaa4b\uaa60-\uaa76\uaa7a\uaa7e-\uaaaf\uaab1\uaab5\uaab6\uaab9-\uaabd\uaac0\uaac2\uaadb-\uaadd\uaae0-\uaaea\uaaf2-\uaaf4\uab01-\uab06\uab09-\uab0e\uab11-\uab16\uab20-\uab26\uab28-\uab2e\uab30-\uab5a\uab5c-\uab5f\uab64\uab65\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 = "\u200c\u200d\xb7\u0300-\u036f\u0387\u0483-\u0487\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u0669\u0670\u06d6-\u06dc\u06df-\u06e4\u06e7\u06e8\u06ea-\u06ed\u06f0-\u06f9\u0711\u0730-\u074a\u07a6-\u07b0\u07c0-\u07c9\u07eb-\u07f3\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0859-\u085b\u08e4-\u0903\u093a-\u093c\u093e-\u094f\u0951-\u0957\u0962\u0963\u0966-\u096f\u0981-\u0983\u09bc\u09be-\u09c4\u09c7\u09c8\u09cb-\u09cd\u09d7\u09e2\u09e3\u09e6-\u09ef\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\u0b62\u0b63\u0b66-\u0b6f\u0b82\u0bbe-\u0bc2\u0bc6-\u0bc8\u0bca-\u0bcd\u0bd7\u0be6-\u0bef\u0c00-\u0c03\u0c3e-\u0c44\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0c66-\u0c6f\u0c81-\u0c83\u0cbc\u0cbe-\u0cc4\u0cc6-\u0cc8\u0cca-\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0ce6-\u0cef\u0d01-\u0d03\u0d3e-\u0d44\u0d46-\u0d48\u0d4a-\u0d4d\u0d57\u0d62\u0d63\u0d66-\u0d6f\u0d82\u0d83\u0dca\u0dcf-\u0dd4\u0dd6\u0dd8-\u0ddf\u0de6-\u0def\u0df2\u0df3\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0e50-\u0e59\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u0ed0-\u0ed9\u0f18\u0f19\u0f20-\u0f29\u0f35\u0f37\u0f39\u0f3e\u0f3f\u0f71-\u0f84\u0f86\u0f87\u0f8d-\u0f97\u0f99-\u0fbc\u0fc6\u102b-\u103e\u1040-\u1049\u1056-\u1059\u105e-\u1060\u1062-\u1064\u1067-\u106d\u1071-\u1074\u1082-\u108d\u108f-\u109d\u135d-\u135f\u1369-\u1371\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b4-\u17d3\u17dd\u17e0-\u17e9\u180b-\u180d\u1810-\u1819\u18a9\u1920-\u192b\u1930-\u193b\u1946-\u194f\u19b0-\u19c0\u19c8\u19c9\u19d0-\u19da\u1a17-\u1a1b\u1a55-\u1a5e\u1a60-\u1a7c\u1a7f-\u1a89\u1a90-\u1a99\u1ab0-\u1abd\u1b00-\u1b04\u1b34-\u1b44\u1b50-\u1b59\u1b6b-\u1b73\u1b80-\u1b82\u1ba1-\u1bad\u1bb0-\u1bb9\u1be6-\u1bf3\u1c24-\u1c37\u1c40-\u1c49\u1c50-\u1c59\u1cd0-\u1cd2\u1cd4-\u1ce8\u1ced\u1cf2-\u1cf4\u1cf8\u1cf9\u1dc0-\u1df5\u1dfc-\u1dff\u203f\u2040\u2054\u20d0-\u20dc\u20e1\u20e5-\u20f0\u2cef-\u2cf1\u2d7f\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua620-\ua629\ua66f\ua674-\ua67d\ua69f\ua6f0\ua6f1\ua802\ua806\ua80b\ua823-\ua827\ua880\ua881\ua8b4-\ua8c4\ua8d0-\ua8d9\ua8e0-\ua8f1\ua900-\ua909\ua926-\ua92d\ua947-\ua953\ua980-\ua983\ua9b3-\ua9c0\ua9d0-\ua9d9\ua9e5\ua9f0-\ua9f9\uaa29-\uaa36\uaa43\uaa4c\uaa4d\uaa50-\uaa59\uaa7b-\uaa7d\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uaaeb-\uaaef\uaaf5\uaaf6\uabe3-\uabea\uabec\uabed\uabf0-\uabf9\ufb1e\ufe00-\ufe0f\ufe20-\ufe2d\ufe33\ufe34\ufe4d-\ufe4f\uff10-\uff19\uff3f";
+
+var nonASCIIidentifierStart = new RegExp("[" + nonASCIIidentifierStartChars + "]");
+var nonASCIIidentifier = new RegExp("[" + nonASCIIidentifierStartChars + nonASCIIidentifierChars + "]");
+nonASCIIidentifierStartChars = nonASCIIidentifierChars = null;
+
+// These are a run-length and offset encoded representation of the
+// >0xffff code points that are a valid part of identifiers. The
+// offset starts at 0x10000, and each pair of numbers represents an
+// offset to the next range, and then a size of the range. They were
+// generated by tools/generate-identifier-regex.js
+var astralIdentifierStartCodes = [0,11,2,25,2,18,2,1,2,14,3,13,35,122,70,52,268,28,4,48,48,31,17,26,6,37,11,29,3,35,5,7,2,4,43,157,99,39,9,51,157,310,10,21,11,7,153,5,3,0,2,43,2,1,4,0,3,22,11,22,10,30,98,21,11,25,71,55,7,1,65,0,16,3,2,2,2,26,45,28,4,28,36,7,2,27,28,53,11,21,11,18,14,17,111,72,955,52,76,44,33,24,27,35,42,34,4,0,13,47,15,3,22,0,38,17,2,24,133,46,39,7,3,1,3,21,2,6,2,1,2,4,4,0,32,4,287,47,21,1,2,0,185,46,82,47,21,0,60,42,502,63,32,0,449,56,1288,920,104,110,2962,1070,13266,568,8,30,114,29,19,47,17,3,32,20,6,18,881,68,12,0,67,12,16481,1,3071,106,6,12,4,8,8,9,5991,84,2,70,2,1,3,0,3,1,3,3,2,11,2,0,2,6,2,64,2,3,3,7,2,6,2,27,2,3,2,4,2,0,4,6,2,339,3,24,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,7,4149,196,1340,3,2,26,2,1,2,0,3,0,2,9,2,3,2,0,2,0,7,0,5,0,2,0,2,0,2,2,2,1,2,0,3,0,2,0,2,0,2,0,2,0,2,1,2,0,3,3,2,6,2,3,2,3,2,0,2,9,2,16,6,2,2,4,2,16,4421,42710,42,4148,12,221,16355,541];
+var astralIdentifierCodes = [509,0,227,0,150,4,294,9,1368,2,2,1,6,3,41,2,5,0,166,1,1306,2,54,14,32,9,16,3,46,10,54,9,7,2,37,13,2,9,52,0,13,2,49,13,16,9,83,11,168,11,6,9,8,2,57,0,2,6,3,1,3,2,10,0,11,1,3,6,4,4,316,19,13,9,214,6,3,8,112,16,16,9,82,12,9,9,535,9,20855,9,135,4,60,6,26,9,1016,45,17,3,19723,1,5319,4,4,5,9,7,3,6,31,3,149,2,1418,49,4305,6,792618,239];
+
+// This has a complexity linear to the value of the code. The
+// assumption is that looking up astral identifier characters is
+// rare.
+function isInAstralSet(code, set) {
+  var pos = 0x10000;
+  for (var i = 0; i < set.length; i += 2) {
+    pos += set[i];
+    if (pos > code) return false;
+    pos += set[i + 1];
+    if (pos >= code) return true;
+  }
+}
+
+// Whether a single character denotes a newline.
+
+var newline = exports.newline = /[\n\r\u2028\u2029]/;
+
+var isNewLine = exports.isNewLine = function(code) {
+  return code === 10 || code === 13 || code === 0x2028 || code == 0x2029;
+};
+
+// Matches a whole line break (where CRLF is considered a single
+// line break). Used to count lines.
+
+var lineBreak = exports.lineBreak = /\r\n|[\n\r\u2028\u2029]/g;
+
+// Test whether a given character code starts an identifier.
+
+var isIdentifierStart = exports.isIdentifierStart = function(code, astral) {
+  if (code < 65) return code === 36;
+  if (code < 91) return true;
+  if (code < 97) return code === 95;
+  if (code < 123) return true;
+  if (code <= 0xffff) return code >= 0xaa && nonASCIIidentifierStart.test(String.fromCharCode(code));
+  if (astral === false) return false;
+  return isInAstralSet(code, astralIdentifierStartCodes);
+};
+
+// Test whether a given character is part of an identifier.
+
+var isIdentifierChar = exports.isIdentifierChar = function(code, astral) {
+  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;
+  if (code <= 0xffff) return code >= 0xaa && nonASCIIidentifier.test(String.fromCharCode(code));
+  if (astral === false) return false;
+  return isInAstralSet(code, astralIdentifierStartCodes) || isInAstralSet(code, astralIdentifierCodes);
+};
+
+// ## Tokenizer
+
+// These are used when `options.locations` is on, for the
+// `startLoc` and `endLoc` properties.
+
+function Position(line, col) {
+  this.line = line;
+  this.column = col;
+}
+
+Position.prototype.offset = function(n) {
+  return new Position(this.line, this.column + n);
+};
+
+// ## 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
+
+var Parser = exports.Parser = function(options, input, startPos) {
+  this.options = options
+  this.loadPlugins(this.options.plugins)
+  this.sourceFile = this.options.sourceFile || null
+  this.isKeyword = this.options.ecmaVersion >= 6 ? isEcma6Keyword : isEcma5AndLessKeyword
+  this.isReservedWord =
+      this.options.ecmaVersion === 3 ? isReservedWord3
+    : this.options.ecmaVersion === 5 ? isReservedWord5
+    : isReservedWord6
+  this.input = input
+
+  // Set up token state
+
+  // The current position of the tokenizer in the input.
+  if (startPos) {
+    this.pos = startPos;
+    this.lineStart = Math.max(0, this.input.lastIndexOf("\n", startPos));
+    this.curLine = this.input.slice(0, this.lineStart).split(newline).length;
+  } else {
+    this.pos = this.lineStart = 0;
+    this.curLine = 1;
+  }
+
+  // Properties of the current token:
+  // Its type
+  this.type = tt.eof;
+  // For tokens that include more information than their type, the value
+  this.value = null;
+  // Its start and end offset
+  this.start = this.end = this.pos;
+  // And, if locations are used, the {line, column} object
+  // corresponding to those offsets
+  this.startLoc = this.endLoc = null;
+
+  // Position information for the previous token
+  this.lastTokEndLoc = this.lastTokStartLoc = null;
+  this.lastTokStart = this.lastTokEnd = this.pos;
+
+  // The context stack is used to superficially track syntactic
+  // context to predict whether a regular expression is allowed in a
+  // given position.
+  this.context = [tc.b_stat];
+  this.exprAllowed = true;
+
+  // Figure out if it's a module code.
+  this.strict = this.inModule = this.options.sourceType === "module";
+
+  // Flags to track whether we are in a function, a generator.
+  this.inFunction = this.inGenerator = false;
+  // Labels in scope.
+  this.labels = [];
+
+  // If enabled, skip leading hashbang line.
+  if (this.pos === 0 && this.options.allowHashBang && this.input.slice(0, 2) === '#!')
+    this.skipLineComment(2);
+};
+
+// Shorthand because we are going to be adding a _lot_ of methods to
+// this.
+var pp = Parser.prototype;
+
+pp.extend = function(name, f) {
+  this[name] = f(this[name]);
+};
+
+pp.loadPlugins = function(plugins) {
+  for (var name in plugins) {
+    var plugin = exports.plugins[name];
+    if (!plugin) throw new Error("Plugin '" + name + "' not found");
+    plugin(this, plugins[name]);
+  }
+};
+
+// Move to the next token
+
+pp.next = function() {
+  if (this.options.onToken)
+    this.options.onToken(new Token(this));
+
+  this.lastTokEnd = this.end;
+  this.lastTokStart = this.start;
+  this.lastTokEndLoc = this.endLoc;
+  this.lastTokStartLoc = this.startLoc;
+  this.nextToken();
+};
+
+pp.getToken = function() {
+  this.next();
+  return new Token(this);
+};
+
+// If we're in an ES6 environment, make parsers iterable
+if (typeof Symbol !== "undefined")
+  pp[Symbol.iterator] = function () {
+    var self = this;
+    return {next: function () {
+      var token = self.getToken();
+      return {
+        done: token.type === tt.eof,
+        value: token
+      };
+    }};
+  };
+
+// Toggle strict mode. Re-reads the next number or string to please
+// pedantic tests (`"use strict"; 010;` should fail).
+
+pp.setStrict = function(strict) {
+  this.strict = strict;
+  if (this.type !== tt.num && this.type !== tt.string) return;
+  this.pos = this.start;
+  if (this.options.locations) {
+    while (this.pos < this.lineStart) {
+      this.lineStart = this.input.lastIndexOf("\n", this.lineStart - 2) + 1;
+      --this.curLine;
+    }
+  }
+  this.nextToken();
+};
+
+pp.curContext = function() {
+  return this.context[this.context.length - 1];
+};
+
+// Read a single token, updating the parser object's token-related
+// properties.
+
+pp.nextToken = function() {
+  var curContext = this.curContext();
+  if (!curContext || !curContext.preserveSpace) this.skipSpace();
+
+  this.start = this.pos;
+  if (this.options.locations) this.startLoc = this.curPosition();
+  if (this.pos >= this.input.length) return this.finishToken(tt.eof);
+
+  if (curContext === tc.q_tmpl) return this.readTmplToken();
+
+  this.readToken(this.fullCharCodeAtPos());
+};
+
+pp.readToken = function(code) {
+  // Identifier or keyword. '\uXXXX' sequences are allowed in
+  // identifiers, so '\' also dispatches to that.
+  if (isIdentifierStart(code, this.options.ecmaVersion >= 6) || code === 92 /* '\' */)
+    return this.readWord();
+
+  return this.getTokenFromCode(code);
+};
+
+pp.fullCharCodeAtPos = function() {
+  var code = this.input.charCodeAt(this.pos);
+  if (code <= 0xd7ff || code >= 0xe000) return code;
+  var next = this.input.charCodeAt(this.pos + 1);
+  return (code << 10) + next - 0x35fdc00;
+};
+
+pp.skipBlockComment = function() {
+  var startLoc = this.options.onComment && this.options.locations && this.curPosition();
+  var start = this.pos, end = this.input.indexOf("*/", this.pos += 2);
+  if (end === -1) this.raise(this.pos - 2, "Unterminated comment");
+  this.pos = end + 2;
+  if (this.options.locations) {
+    lineBreak.lastIndex = start;
+    var match;
+    while ((match = lineBreak.exec(this.input)) && match.index < this.pos) {
+      ++this.curLine;
+      this.lineStart = match.index + match[0].length;
+    }
+  }
+  if (this.options.onComment)
+    this.options.onComment(true, this.input.slice(start + 2, end), start, this.pos,
+                           startLoc, this.options.locations && this.curPosition());
+};
+
+pp.skipLineComment = function(startSkip) {
+  var start = this.pos;
+  var startLoc = this.options.onComment && this.options.locations && this.curPosition();
+  var ch = this.input.charCodeAt(this.pos+=startSkip);
+  while (this.pos < this.input.length && ch !== 10 && ch !== 13 && ch !== 8232 && ch !== 8233) {
+    ++this.pos;
+    ch = this.input.charCodeAt(this.pos);
+  }
+  if (this.options.onComment)
+    this.options.onComment(false, this.input.slice(start + startSkip, this.pos), start, this.pos,
+                           startLoc, this.options.locations && this.curPosition());
+};
+
+// Called at the start of the parse and after every token. Skips
+// whitespace and comments, and.
+
+pp.skipSpace = function() {
+  while (this.pos < this.input.length) {
+    var ch = this.input.charCodeAt(this.pos);
+    if (ch === 32) { // ' '
+      ++this.pos;
+    } else if (ch === 13) {
+      ++this.pos;
+      var next = this.input.charCodeAt(this.pos);
+      if (next === 10) {
+        ++this.pos;
+      }
+      if (this.options.locations) {
+        ++this.curLine;
+        this.lineStart = this.pos;
+      }
+    } else if (ch === 10 || ch === 8232 || ch === 8233) {
+      ++this.pos;
+      if (this.options.locations) {
+        ++this.curLine;
+        this.lineStart = this.pos;
+      }
+    } else if (ch > 8 && ch < 14) {
+      ++this.pos;
+    } else if (ch === 47) { // '/'
+      var next = this.input.charCodeAt(this.pos + 1);
+      if (next === 42) { // '*'
+        this.skipBlockComment();
+      } else if (next === 47) { // '/'
+        this.skipLineComment(2);
+      } else break;
+    } else if (ch === 160) { // '\xa0'
+      ++this.pos;
+    } else if (ch >= 5760 && nonASCIIwhitespace.test(String.fromCharCode(ch))) {
+      ++this.pos;
+    } else {
+      break;
+    }
+  }
+};
+
+pp.curPosition = function() {
+  return new Position(this.curLine, this.pos - this.lineStart);
+};
+
+// The algorithm used to determine whether a regexp can appear at a
+// given point in the program is loosely based on sweet.js' approach.
+// See https://github.com/mozilla/sweet.js/wiki/design
+
+var TokContext = exports.TokContext = function(token, isExpr, preserveSpace) {
+  this.token = token;
+  this.isExpr = isExpr;
+  this.preserveSpace = preserveSpace;
+};
+
+var tc = exports.tokContexts = {
+  b_stat: new TokContext("{", false),
+  b_expr: new TokContext("{", true),
+  b_tmpl: new TokContext("${", true),
+  p_stat: new TokContext("(", false),
+  p_expr: new TokContext("(", true),
+  q_tmpl: new TokContext("`", true, true),
+  f_expr: new TokContext("function", true)
+};
+
+pp.braceIsBlock = function(prevType) {
+  var parent;
+  if (prevType === tt.colon && (parent = this.curContext()).token == "{")
+    return !parent.isExpr;
+  if (prevType === tt._return)
+    return newline.test(this.input.slice(this.lastTokEnd, this.start));
+  if (prevType === tt._else || prevType === tt.semi || prevType === tt.eof)
+    return true;
+  if (prevType == tt.braceL)
+    return this.curContext() === tc.b_stat;
+  return !this.exprAllowed;
+};
+
+// Called at the end of every token. Sets `end`, `val`, and
+// maintains `context` and `exprAllowed`, and skips the space after
+// the token, so that the next one's `start` will point at the
+// right position.
+
+pp.finishToken = function(type, val) {
+  this.end = this.pos;
+  if (this.options.locations) this.endLoc = this.curPosition();
+  var prevType = this.type;
+  this.type = type;
+  this.value = val;
+
+  this.updateContext(prevType);
+};
+
+pp.updateContext = function(prevType) {
+  var update, type = this.type;
+  if (type.keyword && prevType == tt.dot)
+    this.exprAllowed = false;
+  else if (update = type.updateContext)
+    update.call(this, prevType);
+  else
+    this.exprAllowed = type.beforeExpr;
+};
+
+// Token-specific context update code
+
+tt.parenR.updateContext = tt.braceR.updateContext = function() {
+  var out = this.context.pop();
+  if (out === tc.b_stat && this.curContext() === tc.f_expr) {
+    this.context.pop();
+    this.exprAllowed = false;
+  } else if (out === tc.b_tmpl) {
+    this.exprAllowed = true;
+  } else {
+    this.exprAllowed = !(out && out.isExpr);
+  }
+};
+
+tt.braceL.updateContext = function(prevType) {
+  this.context.push(this.braceIsBlock(prevType) ? tc.b_stat : tc.b_expr);
+  this.exprAllowed = true;
+};
+
+tt.dollarBraceL.updateContext = function() {
+  this.context.push(tc.b_tmpl);
+  this.exprAllowed = true;
+};
+
+tt.parenL.updateContext = function(prevType) {
+  var statementParens = prevType === tt._if || prevType === tt._for || prevType === tt._with || prevType === tt._while;
+  this.context.push(statementParens ? tc.p_stat : tc.p_expr);
+  this.exprAllowed = true;
+};
+
+tt.incDec.updateContext = function() {
+  // tokExprAllowed stays unchanged
+};
+
+tt._function.updateContext = function() {
+  if (this.curContext() !== tc.b_stat)
+    this.context.push(tc.f_expr);
+  this.exprAllowed = false;
+};
+
+tt.backQuote.updateContext = function() {
+  if (this.curContext() === tc.q_tmpl)
+    this.context.pop();
+  else
+    this.context.push(tc.q_tmpl);
+  this.exprAllowed = false;
+};
+
+// ### 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.
+//
+pp.readToken_dot = function() {
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next >= 48 && next <= 57) return this.readNumber(true);
+  var next2 = this.input.charCodeAt(this.pos + 2);
+  if (this.options.ecmaVersion >= 6 && next === 46 && next2 === 46) { // 46 = dot '.'
+    this.pos += 3;
+    return this.finishToken(tt.ellipsis);
+  } else {
+    ++this.pos;
+    return this.finishToken(tt.dot);
+  }
+};
+
+pp.readToken_slash = function() { // '/'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (this.exprAllowed) {++this.pos; return this.readRegexp();}
+  if (next === 61) return this.finishOp(tt.assign, 2);
+  return this.finishOp(tt.slash, 1);
+};
+
+pp.readToken_mult_modulo = function(code) { // '%*'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === 61) return this.finishOp(tt.assign, 2);
+  return this.finishOp(code === 42 ? tt.star : tt.modulo, 1);
+};
+
+pp.readToken_pipe_amp = function(code) { // '|&'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === code) return this.finishOp(code === 124 ? tt.logicalOR : tt.logicalAND, 2);
+  if (next === 61) return this.finishOp(tt.assign, 2);
+  return this.finishOp(code === 124 ? tt.bitwiseOR : tt.bitwiseAND, 1);
+};
+
+pp.readToken_caret = function() { // '^'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === 61) return this.finishOp(tt.assign, 2);
+  return this.finishOp(tt.bitwiseXOR, 1);
+};
+
+pp.readToken_plus_min = function(code) { // '+-'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === code) {
+    if (next == 45 && this.input.charCodeAt(this.pos + 2) == 62 &&
+        newline.test(this.input.slice(this.lastTokEnd, this.pos))) {
+      // A `-->` line comment
+      this.skipLineComment(3);
+      this.skipSpace();
+      return this.nextToken();
+    }
+    return this.finishOp(tt.incDec, 2);
+  }
+  if (next === 61) return this.finishOp(tt.assign, 2);
+  return this.finishOp(tt.plusMin, 1);
+};
+
+pp.readToken_lt_gt = function(code) { // '<>'
+  var next = this.input.charCodeAt(this.pos + 1);
+  var size = 1;
+  if (next === code) {
+    size = code === 62 && this.input.charCodeAt(this.pos + 2) === 62 ? 3 : 2;
+    if (this.input.charCodeAt(this.pos + size) === 61) return this.finishOp(tt.assign, size + 1);
+    return this.finishOp(tt.bitShift, size);
+  }
+  if (next == 33 && code == 60 && this.input.charCodeAt(this.pos + 2) == 45 &&
+      this.input.charCodeAt(this.pos + 3) == 45) {
+    if (this.inModule) unexpected();
+    // `<!--`, an XML-style comment that should be interpreted as a line comment
+    this.skipLineComment(4);
+    this.skipSpace();
+    return this.nextToken();
+  }
+  if (next === 61)
+    size = this.input.charCodeAt(this.pos + 2) === 61 ? 3 : 2;
+  return this.finishOp(tt.relational, size);
+};
+
+pp.readToken_eq_excl = function(code) { // '=!'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === 61) return this.finishOp(tt.equality, this.input.charCodeAt(this.pos + 2) === 61 ? 3 : 2);
+  if (code === 61 && next === 62 && this.options.ecmaVersion >= 6) { // '=>'
+    this.pos += 2;
+    return this.finishToken(tt.arrow);
+  }
+  return this.finishOp(code === 61 ? tt.eq : tt.prefix, 1);
+};
+
+pp.getTokenFromCode = function(code) {
+  switch (code) {
+    // The interpretation of a dot depends on whether it is followed
+    // by a digit or another two dots.
+  case 46: // '.'
+    return this.readToken_dot();
+
+    // Punctuation tokens.
+  case 40: ++this.pos; return this.finishToken(tt.parenL);
+  case 41: ++this.pos; return this.finishToken(tt.parenR);
+  case 59: ++this.pos; return this.finishToken(tt.semi);
+  case 44: ++this.pos; return this.finishToken(tt.comma);
+  case 91: ++this.pos; return this.finishToken(tt.bracketL);
+  case 93: ++this.pos; return this.finishToken(tt.bracketR);
+  case 123: ++this.pos; return this.finishToken(tt.braceL);
+  case 125: ++this.pos; return this.finishToken(tt.braceR);
+  case 58: ++this.pos; return this.finishToken(tt.colon);
+  case 63: ++this.pos; return this.finishToken(tt.question);
+
+  case 96: // '`'
+    if (this.options.ecmaVersion < 6) break;
+    ++this.pos;
+    return this.finishToken(tt.backQuote);
+
+  case 48: // '0'
+    var next = this.input.charCodeAt(this.pos + 1);
+    if (next === 120 || next === 88) return this.readRadixNumber(16); // '0x', '0X' - hex number
+    if (this.options.ecmaVersion >= 6) {
+      if (next === 111 || next === 79) return this.readRadixNumber(8); // '0o', '0O' - octal number
+      if (next === 98 || next === 66) return this.readRadixNumber(2); // '0b', '0B' - binary number
+    }
+    // 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 this.readNumber(false);
+
+    // Quotes produce strings.
+  case 34: case 39: // '"', "'"
+    return this.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 this.readToken_slash();
+
+  case 37: case 42: // '%*'
+    return this.readToken_mult_modulo(code);
+
+  case 124: case 38: // '|&'
+    return this.readToken_pipe_amp(code);
+
+  case 94: // '^'
+    return this.readToken_caret();
+
+  case 43: case 45: // '+-'
+    return this.readToken_plus_min(code);
+
+  case 60: case 62: // '<>'
+    return this.readToken_lt_gt(code);
+
+  case 61: case 33: // '=!'
+    return this.readToken_eq_excl(code);
+
+  case 126: // '~'
+    return this.finishOp(tt.prefix, 1);
+  }
+
+  this.raise(this.pos, "Unexpected character '" + codePointToString(code) + "'");
+};
+
+pp.finishOp = function(type, size) {
+  var str = this.input.slice(this.pos, this.pos + size);
+  this.pos += size;
+  return this.finishToken(type, str);
+};
+
+var regexpUnicodeSupport = false;
+try { new RegExp("\uffff", "u"); regexpUnicodeSupport = true; }
+catch(e) {}
+
+// Parse a regular expression. Some context-awareness is necessary,
+// since a '/' inside a '[]' set does not end the expression.
+
+pp.readRegexp = function() {
+  var content = "", escaped, inClass, start = this.pos;
+  for (;;) {
+    if (this.pos >= this.input.length) this.raise(start, "Unterminated regular expression");
+    var ch = this.input.charAt(this.pos);
+    if (newline.test(ch)) this.raise(start, "Unterminated regular expression");
+    if (!escaped) {
+      if (ch === "[") inClass = true;
+      else if (ch === "]" && inClass) inClass = false;
+      else if (ch === "/" && !inClass) break;
+      escaped = ch === "\\";
+    } else escaped = false;
+    ++this.pos;
+  }
+  var content = this.input.slice(start, this.pos);
+  ++this.pos;
+  // Need to use `readWord1` because '\uXXXX' sequences are allowed
+  // here (don't ask).
+  var mods = this.readWord1();
+  var tmp = content;
+  if (mods) {
+    var validFlags = /^[gmsiy]*$/;
+    if (this.options.ecmaVersion >= 6) validFlags = /^[gmsiyu]*$/;
+    if (!validFlags.test(mods)) this.raise(start, "Invalid regular expression flag");
+    if (mods.indexOf('u') >= 0 && !regexpUnicodeSupport) {
+      // Replace each astral symbol and every Unicode escape sequence that
+      // possibly represents an astral symbol or a paired surrogate with a
+      // single ASCII symbol to avoid throwing on regular expressions that
+      // are only valid in combination with the `/u` flag.
+      // Note: replacing with the ASCII symbol `x` might cause false
+      // negatives in unlikely scenarios. For example, `[\u{61}-b]` is a
+      // perfectly valid pattern that is equivalent to `[a-b]`, but it would
+      // be replaced by `[x-b]` which throws an error.
+      tmp = tmp.replace(/\\u([a-fA-F0-9]{4})|\\u\{([0-9a-fA-F]+)\}|[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "x")
+    }
+  }
+  // Detect invalid regular expressions.
+  try {
+    new RegExp(tmp);
+  } catch (e) {
+    if (e instanceof SyntaxError) this.raise(start, "Error parsing regular expression: " + e.message);
+    this.raise(e);
+  }
+  // Get a regular expression object for this pattern-flag pair, or `null` in
+  // case the current environment doesn't support the flags it uses.
+  try {
+    var value = new RegExp(content, mods);
+  } catch (err) {
+    value = null;
+  }
+  return this.finishToken(tt.regexp, {pattern: content, flags: mods, value: 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.
+
+pp.readInt = function(radix, len) {
+  var start = this.pos, total = 0;
+  for (var i = 0, e = len == null ? Infinity : len; i < e; ++i) {
+    var code = this.input.charCodeAt(this.pos), 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;
+    ++this.pos;
+    total = total * radix + val;
+  }
+  if (this.pos === start || len != null && this.pos - start !== len) return null;
+
+  return total;
+};
+
+pp.readRadixNumber = function(radix) {
+  this.pos += 2; // 0x
+  var val = this.readInt(radix);
+  if (val == null) this.raise(this.start + 2, "Expected number in radix " + radix);
+  if (isIdentifierStart(this.fullCharCodeAtPos())) this.raise(this.pos, "Identifier directly after number");
+  return this.finishToken(tt.num, val);
+};
+
+// Read an integer, octal integer, or floating-point number.
+
+pp.readNumber = function(startsWithDot) {
+  var start = this.pos, isFloat = false, octal = this.input.charCodeAt(this.pos) === 48;
+  if (!startsWithDot && this.readInt(10) === null) this.raise(start, "Invalid number");
+  if (this.input.charCodeAt(this.pos) === 46) {
+    ++this.pos;
+    this.readInt(10);
+    isFloat = true;
+  }
+  var next = this.input.charCodeAt(this.pos);
+  if (next === 69 || next === 101) { // 'eE'
+    next = this.input.charCodeAt(++this.pos);
+    if (next === 43 || next === 45) ++this.pos; // '+-'
+    if (this.readInt(10) === null) this.raise(start, "Invalid number");
+    isFloat = true;
+  }
+  if (isIdentifierStart(this.fullCharCodeAtPos())) this.raise(this.pos, "Identifier directly after number");
+
+  var str = this.input.slice(start, this.pos), val;
+  if (isFloat) val = parseFloat(str);
+  else if (!octal || str.length === 1) val = parseInt(str, 10);
+  else if (/[89]/.test(str) || this.strict) this.raise(start, "Invalid number");
+  else val = parseInt(str, 8);
+  return this.finishToken(tt.num, val);
+};
+
+// Read a string value, interpreting backslash-escapes.
+
+pp.readCodePoint = function() {
+  var ch = this.input.charCodeAt(this.pos), code;
+
+  if (ch === 123) {
+    if (this.options.ecmaVersion < 6) this.unexpected();
+    ++this.pos;
+    code = this.readHexChar(this.input.indexOf('}', this.pos) - this.pos);
+    ++this.pos;
+    if (code > 0x10FFFF) this.unexpected();
+  } else {
+    code = this.readHexChar(4);
+  }
+  return code;
+};
+
+function codePointToString(code) {
+  // UTF-16 Decoding
+  if (code <= 0xFFFF) return String.fromCharCode(code);
+  return String.fromCharCode(((code - 0x10000) >> 10) + 0xD800,
+                             ((code - 0x10000) & 1023) + 0xDC00);
+}
+
+pp.readString = function(quote) {
+  var out = "", chunkStart = ++this.pos;
+  for (;;) {
+    if (this.pos >= this.input.length) this.raise(this.start, "Unterminated string constant");
+    var ch = this.input.charCodeAt(this.pos);
+    if (ch === quote) break;
+    if (ch === 92) { // '\'
+      out += this.input.slice(chunkStart, this.pos);
+      out += this.readEscapedChar();
+      chunkStart = this.pos;
+    } else {
+      if (isNewLine(ch)) this.raise(this.start, "Unterminated string constant");
+      ++this.pos;
+    }
+  }
+  out += this.input.slice(chunkStart, this.pos++);
+  return this.finishToken(tt.string, out);
+};
+
+// Reads template string tokens.
+
+pp.readTmplToken = function() {
+  var out = "", chunkStart = this.pos;
+  for (;;) {
+    if (this.pos >= this.input.length) this.raise(this.start, "Unterminated template");
+    var ch = this.input.charCodeAt(this.pos);
+    if (ch === 96 || ch === 36 && this.input.charCodeAt(this.pos + 1) === 123) { // '`', '${'
+      if (this.pos === this.start && this.type === tt.template) {
+        if (ch === 36) {
+          this.pos += 2;
+          return this.finishToken(tt.dollarBraceL);
+        } else {
+          ++this.pos;
+          return this.finishToken(tt.backQuote);
+        }
+      }
+      out += this.input.slice(chunkStart, this.pos);
+      return this.finishToken(tt.template, out);
+    }
+    if (ch === 92) { // '\'
+      out += this.input.slice(chunkStart, this.pos);
+      out += this.readEscapedChar();
+      chunkStart = this.pos;
+    } else if (isNewLine(ch)) {
+      out += this.input.slice(chunkStart, this.pos);
+      ++this.pos;
+      if (ch === 13 && this.input.charCodeAt(this.pos) === 10) {
+        ++this.pos;
+        out += "\n";
+      } else {
+        out += String.fromCharCode(ch);
+      }
+      if (this.options.locations) {
+        ++this.curLine;
+        this.lineStart = this.pos;
+      }
+      chunkStart = this.pos;
+    } else {
+      ++this.pos;
+    }
+  }
+};
+
+// Used to read escaped characters
+
+pp.readEscapedChar = function() {
+  var ch = this.input.charCodeAt(++this.pos);
+  var octal = /^[0-7]+/.exec(this.input.slice(this.pos, this.pos + 3));
+  if (octal) octal = octal[0];
+  while (octal && parseInt(octal, 8) > 255) octal = octal.slice(0, -1);
+  if (octal === "0") octal = null;
+  ++this.pos;
+  if (octal) {
+    if (this.strict) this.raise(this.pos - 2, "Octal literal in strict mode");
+    this.pos += octal.length - 1;
+    return String.fromCharCode(parseInt(octal, 8));
+  } else {
+    switch (ch) {
+    case 110: return "\n"; // 'n' -> '\n'
+    case 114: return "\r"; // 'r' -> '\r'
+    case 120: return String.fromCharCode(this.readHexChar(2)); // 'x'
+    case 117: return codePointToString(this.readCodePoint()); // 'u'
+    case 116: return "\t"; // 't' -> '\t'
+    case 98: return "\b"; // 'b' -> '\b'
+    case 118: return "\u000b"; // 'v' -> '\u000b'
+    case 102: return "\f"; // 'f' -> '\f'
+    case 48: return "\0"; // 0 -> '\0'
+    case 13: if (this.input.charCodeAt(this.pos) === 10) ++this.pos; // '\r\n'
+    case 10: // ' \n'
+      if (this.options.locations) { this.lineStart = this.pos; ++this.curLine; }
+      return "";
+    default: return String.fromCharCode(ch);
+    }
+  }
+};
+
+// Used to read character escape sequences ('\x', '\u', '\U').
+
+pp.readHexChar = function(len) {
+  var n = this.readInt(16, len);
+  if (n === null) this.raise(this.start, "Bad character escape sequence");
+  return 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.
+
+var containsEsc;
+
+// Read an identifier, and return it as a string. Sets `containsEsc`
+// to whether the word contained a '\u' escape.
+//
+// Incrementally adds only escaped chars, adding other chunks as-is
+// as a micro-optimization.
+
+pp.readWord1 = function() {
+  containsEsc = false;
+  var word = "", first = true, chunkStart = this.pos;
+  var astral = this.options.ecmaVersion >= 6;
+  while (this.pos < this.input.length) {
+    var ch = this.fullCharCodeAtPos();
+    if (isIdentifierChar(ch, astral)) {
+      this.pos += ch <= 0xffff ? 1 : 2;
+    } else if (ch === 92) { // "\"
+      containsEsc = true;
+      word += this.input.slice(chunkStart, this.pos);
+      var escStart = this.pos;
+      if (this.input.charCodeAt(++this.pos) != 117) // "u"
+        this.raise(this.pos, "Expecting Unicode escape sequence \\uXXXX");
+      ++this.pos;
+      var esc = this.readCodePoint();
+      if (!(first ? isIdentifierStart : isIdentifierChar)(esc, astral))
+        this.raise(escStart, "Invalid Unicode escape");
+      word += codePointToString(esc);
+      chunkStart = this.pos;
+    } else {
+      break;
+    }
+    first = false;
+  }
+  return word + this.input.slice(chunkStart, this.pos);
+};
+
+// Read an identifier or keyword token. Will check for reserved
+// words when necessary.
+
+pp.readWord = function() {
+  var word = this.readWord1();
+  var type = tt.name;
+  if ((this.options.ecmaVersion >= 6 || !containsEsc) && this.isKeyword(word))
+    type = keywordTypes[word];
+  return this.finishToken(type, word);
+};
+
+// 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.
+
+pp.raise = function(pos, message) {
+  var loc = getLineInfo(this.input, pos);
+  message += " (" + loc.line + ":" + loc.column + ")";
+  var err = new SyntaxError(message);
+  err.pos = pos; err.loc = loc; err.raisedAt = this.pos;
+  throw err;
+};
+
+pp.currentPos = function() {
+  return this.options.locations ? [this.start, this.startLoc] : this.start;
+};
+
+// ### Parser utilities
+
+// Start an AST node, attaching a start offset.
+
+var Node = exports.Node = function() {};
+
+var SourceLocation = exports.SourceLocation = function(p, start, end) {
+  this.start = start;
+  this.end = end;
+  if (p.sourceFile !== null) this.source = p.sourceFile;
+};
+
+pp.startNode = function() {
+  var node = new Node;
+  node.start = this.start;
+  if (this.options.locations)
+    node.loc = new SourceLocation(this, this.startLoc);
+  if (this.options.directSourceFile)
+    node.sourceFile = this.options.directSourceFile;
+  if (this.options.ranges)
+    node.range = [this.start, 0];
+  return node;
+};
+
+pp.startNodeAt = function(pos) {
+  var node = new Node, start = pos;
+  if (this.options.locations) {
+    node.loc = new SourceLocation(this, start[1]);
+    start = pos[0];
+  }
+  node.start = start;
+  if (this.options.directSourceFile)
+    node.sourceFile = this.options.directSourceFile;
+  if (this.options.ranges)
+    node.range = [start, 0];
+  return node;
+};
+
+// Finish an AST node, adding `type` and `end` properties.
+
+pp.finishNode = function(node, type) {
+  node.type = type;
+  node.end = this.lastTokEnd;
+  if (this.options.locations)
+    node.loc.end = this.lastTokEndLoc;
+  if (this.options.ranges)
+    node.range[1] = this.lastTokEnd;
+  return node;
+};
+
+// Finish node at given position
+
+pp.finishNodeAt = function(node, type, pos) {
+  if (this.options.locations) { node.loc.end = pos[1]; pos = pos[0]; }
+  node.type = type;
+  node.end = pos;
+  if (this.options.ranges)
+    node.range[1] = pos;
+  return node;
+};
+
+// Test whether a statement node is the string literal `"use strict"`.
+
+pp.isUseStrict = function(stmt) {
+  return this.options.ecmaVersion >= 5 && 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.
+
+pp.eat = function(type) {
+  if (this.type === type) {
+    this.next();
+    return true;
+  } else {
+    return false;
+  }
+};
+
+// Tests whether parsed token is a contextual keyword.
+
+pp.isContextual = function(name) {
+  return this.type === tt.name && this.value === name;
+};
+
+// Consumes contextual keyword if possible.
+
+pp.eatContextual = function(name) {
+  return this.value === name && this.eat(tt.name);
+};
+
+// Asserts that following token is given contextual keyword.
+
+pp.expectContextual = function(name) {
+  if (!this.eatContextual(name)) this.unexpected();
+};
+
+// Test whether a semicolon can be inserted at the current position.
+
+pp.canInsertSemicolon = function() {
+  return this.type === tt.eof ||
+    this.type === tt.braceR ||
+    newline.test(this.input.slice(this.lastTokEnd, this.start));
+};
+
+pp.insertSemicolon = function() {
+  if (this.canInsertSemicolon()) {
+    if (this.options.onInsertedSemicolon)
+      this.options.onInsertedSemicolon(this.lastTokEnd, this.lastTokEndLoc)
+    return true;
+  }
+};
+
+// Consume a semicolon, or, failing that, see if we are allowed to
+// pretend that there is a semicolon at this position.
+
+pp.semicolon = function() {
+  if (!this.eat(tt.semi) && !this.insertSemicolon()) this.unexpected();
+};
+
+pp.afterTrailingComma = function(tokType) {
+  if (this.type == tokType) {
+    if (this.options.onTrailingComma)
+      this.options.onTrailingComma(this.lastTokStart, this.lastTokStartLoc);
+    this.next();
+    return true;
+  }
+};
+
+// Expect a token of a given type. If found, consume it, otherwise,
+// raise an unexpected token error.
+
+pp.expect = function(type) {
+  this.eat(type) || this.unexpected();
+};
+
+// Raise an unexpected token error.
+
+pp.unexpected = function(pos) {
+  this.raise(pos != null ? pos : this.start, "Unexpected token");
+};
+
+// Convert existing expression atom to assignable pattern
+// if possible.
+
+pp.toAssignable = function(node, isBinding) {
+  if (this.options.ecmaVersion >= 6 && node) {
+    switch (node.type) {
+    case "Identifier":
+    case "ObjectPattern":
+    case "ArrayPattern":
+    case "AssignmentPattern":
+      break;
+
+    case "ObjectExpression":
+      node.type = "ObjectPattern";
+      for (var i = 0; i < node.properties.length; i++) {
+        var prop = node.properties[i];
+        if (prop.kind !== "init") this.raise(prop.key.start, "Object pattern can't contain getter or setter");
+        this.toAssignable(prop.value, isBinding);
+      }
+      break;
+
+    case "ArrayExpression":
+      node.type = "ArrayPattern";
+      this.toAssignableList(node.elements, isBinding);
+      break;
+
+    case "AssignmentExpression":
+      if (node.operator === "=") {
+        node.type = "AssignmentPattern";
+      } else {
+        this.raise(node.left.end, "Only '=' operator can be used for specifying default value.");
+      }
+      break;
+
+    case "MemberExpression":
+      if (!isBinding) break;
+
+    default:
+      this.raise(node.start, "Assigning to rvalue");
+    }
+  }
+  return node;
+};
+
+// Convert list of expression atoms to binding list.
+
+pp.toAssignableList = function(exprList, isBinding) {
+  var end = exprList.length;
+  if (end) {
+    var last = exprList[end - 1];
+    if (last && last.type == "RestElement") {
+      --end;
+    } else if (last && last.type == "SpreadElement") {
+      last.type = "RestElement";
+      var arg = last.argument;
+      this.toAssignable(arg, isBinding);
+      if (arg.type !== "Identifier" && arg.type !== "MemberExpression" && arg.type !== "ArrayPattern")
+        this.unexpected(arg.start);
+      --end;
+    }
+  }
+  for (var i = 0; i < end; i++) {
+    var elt = exprList[i];
+    if (elt) this.toAssignable(elt, isBinding);
+  }
+  return exprList;
+};
+
+// Parses spread element.
+
+pp.parseSpread = function(refShorthandDefaultPos) {
+  var node = this.startNode();
+  this.next();
+  node.argument = this.parseMaybeAssign(refShorthandDefaultPos);
+  return this.finishNode(node, "SpreadElement");
+};
+
+pp.parseRest = function() {
+  var node = this.startNode();
+  this.next();
+  node.argument = this.type === tt.name || this.type === tt.bracketL ? this.parseBindingAtom() : this.unexpected();
+  return this.finishNode(node, "RestElement");
+};
+
+// Parses lvalue (assignable) atom.
+
+pp.parseBindingAtom = function() {
+  if (this.options.ecmaVersion < 6) return this.parseIdent();
+  switch (this.type) {
+  case tt.name:
+    return this.parseIdent();
+
+  case tt.bracketL:
+    var node = this.startNode();
+    this.next();
+    node.elements = this.parseBindingList(tt.bracketR, true, true);
+    return this.finishNode(node, "ArrayPattern");
+
+  case tt.braceL:
+    return this.parseObj(true);
+
+  default:
+    this.unexpected();
+  }
+};
+
+pp.parseBindingList = function(close, allowEmpty, allowTrailingComma) {
+  var elts = [], first = true;
+  while (!this.eat(close)) {
+    if (first) first = false;
+    else this.expect(tt.comma);
+    if (allowEmpty && this.type === tt.comma) {
+      elts.push(null);
+    } else if (allowTrailingComma && this.afterTrailingComma(close)) {
+      break;
+    } else if (this.type === tt.ellipsis) {
+      elts.push(this.parseRest());
+      this.expect(close);
+      break;
+    } else {
+      elts.push(this.parseMaybeDefault());
+    }
+  }
+  return elts;
+};
+
+// Parses assignment pattern around given atom if possible.
+
+pp.parseMaybeDefault = function(startPos, left) {
+  startPos = startPos || this.currentPos();
+  left = left || this.parseBindingAtom();
+  if (!this.eat(tt.eq)) return left;
+  var node = this.startNodeAt(startPos);
+  node.operator = "=";
+  node.left = left;
+  node.right = this.parseMaybeAssign();
+  return this.finishNode(node, "AssignmentPattern");
+};
+
+// Check if property name clashes with already added.
+// Object/class 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.
+
+pp.checkPropClash = function(prop, propHash) {
+  if (this.options.ecmaVersion >= 6) return;
+  var key = prop.key, name;
+  switch (key.type) {
+  case "Identifier": name = key.name; break;
+  case "Literal": name = String(key.value); break;
+  default: return;
+  }
+  var kind = prop.kind || "init", other;
+  if (has(propHash, name)) {
+    other = propHash[name];
+    var isGetSet = kind !== "init";
+    if ((this.strict || isGetSet) && other[kind] || !(isGetSet ^ other.init))
+      this.raise(key.start, "Redefinition of property");
+  } else {
+    other = propHash[name] = {
+      init: false,
+      get: false,
+      set: false
+    };
+  }
+  other[kind] = true;
+};
+
+// Verify that a node is an lval — something that can be assigned
+// to.
+
+pp.checkLVal = function(expr, isBinding, checkClashes) {
+  switch (expr.type) {
+  case "Identifier":
+    if (this.strict && (isStrictBadIdWord(expr.name) || isStrictReservedWord(expr.name)))
+      this.raise(expr.start, (isBinding ? "Binding " : "Assigning to ") + expr.name + " in strict mode");
+    if (checkClashes) {
+      if (has(checkClashes, expr.name))
+        this.raise(expr.start, "Argument name clash in strict mode");
+      checkClashes[expr.name] = true;
+    }
+    break;
+
+  case "MemberExpression":
+    if (isBinding) this.raise(expr.start, (isBinding ? "Binding" : "Assigning to") + " member expression");
+    break;
+
+  case "ObjectPattern":
+    for (var i = 0; i < expr.properties.length; i++)
+      this.checkLVal(expr.properties[i].value, isBinding, checkClashes);
+    break;
+
+  case "ArrayPattern":
+    for (var i = 0; i < expr.elements.length; i++) {
+      var elem = expr.elements[i];
+      if (elem) this.checkLVal(elem, isBinding, checkClashes);
+    }
+    break;
+
+  case "AssignmentPattern":
+    this.checkLVal(expr.left, isBinding, checkClashes);
+    break;
+
+  case "RestElement":
+    this.checkLVal(expr.argument, isBinding, checkClashes);
+    break;
+
+  default:
+    this.raise(expr.start, (isBinding ? "Binding" : "Assigning to") + " rvalue");
+  }
+};
+
+// ### 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.
+
+pp.parseTopLevel = function(node) {
+  var first = true;
+  if (!node.body) node.body = [];
+  while (this.type !== tt.eof) {
+    var stmt = this.parseStatement(true, true);
+    node.body.push(stmt);
+    if (first && this.isUseStrict(stmt)) this.setStrict(true);
+    first = false;
+  }
+  this.next();
+  if (this.options.ecmaVersion >= 6) {
+    node.sourceType = this.options.sourceType;
+  }
+  return this.finishNode(node, "Program");
+};
+
+var loopLabel = {kind: "loop"}, 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.
+
+pp.parseStatement = function(declaration, topLevel) {
+  var starttype = this.type, node = this.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 tt._break: case tt._continue: return this.parseBreakContinueStatement(node, starttype.keyword);
+  case tt._debugger: return this.parseDebuggerStatement(node);
+  case tt._do: return this.parseDoStatement(node);
+  case tt._for: return this.parseForStatement(node);
+  case tt._function:
+    if (!declaration && this.options.ecmaVersion >= 6) this.unexpected();
+    return this.parseFunctionStatement(node);
+  case tt._class:
+    if (!declaration) this.unexpected();
+    return this.parseClass(node, true);
+  case tt._if: return this.parseIfStatement(node);
+  case tt._return: return this.parseReturnStatement(node);
+  case tt._switch: return this.parseSwitchStatement(node);
+  case tt._throw: return this.parseThrowStatement(node);
+  case tt._try: return this.parseTryStatement(node);
+  case tt._let: case tt._const: if (!declaration) this.unexpected(); // NOTE: falls through to _var
+  case tt._var: return this.parseVarStatement(node, starttype);
+  case tt._while: return this.parseWhileStatement(node);
+  case tt._with: return this.parseWithStatement(node);
+  case tt.braceL: return this.parseBlock(); // no point creating a function for this
+  case tt.semi: return this.parseEmptyStatement(node);
+  case tt._export:
+  case tt._import:
+    if (!this.options.allowImportExportEverywhere) {
+      if (!topLevel)
+        this.raise(this.start, "'import' and 'export' may only appear at the top level");
+      if (!this.inModule)
+        this.raise(this.start, "'import' and 'export' may appear only with 'sourceType: module'");
+    }
+    return starttype === tt._import ? this.parseImport(node) : this.parseExport(node);
+
+    // 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 = this.value, expr = this.parseExpression();
+    if (starttype === tt.name && expr.type === "Identifier" && this.eat(tt.colon))
+      return this.parseLabeledStatement(node, maybeName, expr);
+    else return this.parseExpressionStatement(node, expr);
+  }
+};
+
+pp.parseBreakContinueStatement = function(node, keyword) {
+  var isBreak = keyword == "break";
+  this.next();
+  if (this.eat(tt.semi) || this.insertSemicolon()) node.label = null;
+  else if (this.type !== tt.name) this.unexpected();
+  else {
+    node.label = this.parseIdent();
+    this.semicolon();
+  }
+
+  // Verify that there is an actual destination to break or
+  // continue to.
+  for (var i = 0; i < this.labels.length; ++i) {
+    var lab = this.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 === this.labels.length) this.raise(node.start, "Unsyntactic " + keyword);
+  return this.finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement");
+};
+
+pp.parseDebuggerStatement = function(node) {
+  this.next();
+  this.semicolon();
+  return this.finishNode(node, "DebuggerStatement");
+};
+
+pp.parseDoStatement = function(node) {
+  this.next();
+  this.labels.push(loopLabel);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  this.expect(tt._while);
+  node.test = this.parseParenExpression();
+  if (this.options.ecmaVersion >= 6)
+    this.eat(tt.semi);
+  else
+    this.semicolon();
+  return this.finishNode(node, "DoWhileStatement");
+};
+
+// Disambiguating between a `for` and a `for`/`in` or `for`/`of`
+// 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` or `of`. When there is no init
+// part (semicolon immediately after the opening parenthesis), it
+// is a regular `for` loop.
+
+pp.parseForStatement = function(node) {
+  this.next();
+  this.labels.push(loopLabel);
+  this.expect(tt.parenL);
+  if (this.type === tt.semi) return this.parseFor(node, null);
+  if (this.type === tt._var || this.type === tt._let || this.type === tt._const) {
+    var init = this.startNode(), varKind = this.type;
+    this.next();
+    this.parseVar(init, true, varKind);
+    this.finishNode(init, "VariableDeclaration");
+    if ((this.type === tt._in || (this.options.ecmaVersion >= 6 && this.isContextual("of"))) && init.declarations.length === 1 &&
+        !(varKind !== tt._var && init.declarations[0].init))
+      return this.parseForIn(node, init);
+    return this.parseFor(node, init);
+  }
+  var refShorthandDefaultPos = {start: 0};
+  var init = this.parseExpression(true, refShorthandDefaultPos);
+  if (this.type === tt._in || (this.options.ecmaVersion >= 6 && this.isContextual("of"))) {
+    this.toAssignable(init);
+    this.checkLVal(init);
+    return this.parseForIn(node, init);
+  } else if (refShorthandDefaultPos.start) {
+    this.unexpected(refShorthandDefaultPos.start);
+  }
+  return this.parseFor(node, init);
+};
+
+pp.parseFunctionStatement = function(node) {
+  this.next();
+  return this.parseFunction(node, true);
+};
+
+pp.parseIfStatement = function(node) {
+  this.next();
+  node.test = this.parseParenExpression();
+  node.consequent = this.parseStatement(false);
+  node.alternate = this.eat(tt._else) ? this.parseStatement(false) : null;
+  return this.finishNode(node, "IfStatement");
+};
+
+pp.parseReturnStatement = function(node) {
+  if (!this.inFunction && !this.options.allowReturnOutsideFunction)
+    this.raise(this.start, "'return' outside of function");
+  this.next();
+
+  // In `return` (and `break`/`continue`), the keywords with
+  // optional arguments, we eagerly look for a semicolon or the
+  // possibility to insert one.
+
+  if (this.eat(tt.semi) || this.insertSemicolon()) node.argument = null;
+  else { node.argument = this.parseExpression(); this.semicolon(); }
+  return this.finishNode(node, "ReturnStatement");
+};
+
+pp.parseSwitchStatement = function(node) {
+  this.next();
+  node.discriminant = this.parseParenExpression();
+  node.cases = [];
+  this.expect(tt.braceL);
+  this.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; this.type != tt.braceR;) {
+    if (this.type === tt._case || this.type === tt._default) {
+      var isCase = this.type === tt._case;
+      if (cur) this.finishNode(cur, "SwitchCase");
+      node.cases.push(cur = this.startNode());
+      cur.consequent = [];
+      this.next();
+      if (isCase) cur.test = this.parseExpression();
+      else {
+        if (sawDefault) this.raise(this.lastTokStart, "Multiple default clauses"); sawDefault = true;
+        cur.test = null;
+      }
+      this.expect(tt.colon);
+    } else {
+      if (!cur) this.unexpected();
+      cur.consequent.push(this.parseStatement(true));
+    }
+  }
+  if (cur) this.finishNode(cur, "SwitchCase");
+  this.next(); // Closing brace
+  this.labels.pop();
+  return this.finishNode(node, "SwitchStatement");
+};
+
+pp.parseThrowStatement = function(node) {
+  this.next();
+  if (newline.test(this.input.slice(this.lastTokEnd, this.start)))
+    this.raise(this.lastTokEnd, "Illegal newline after throw");
+  node.argument = this.parseExpression();
+  this.semicolon();
+  return this.finishNode(node, "ThrowStatement");
+};
+
+// Reused empty array added for node fields that are always empty.
+
+var empty = [];
+
+
+pp.parseTryStatement = function(node) {
+  this.next();
+  node.block = this.parseBlock();
+  node.handler = null;
+  if (this.type === tt._catch) {
+    var clause = this.startNode();
+    this.next();
+    this.expect(tt.parenL);
+    clause.param = this.parseBindingAtom();
+    this.checkLVal(clause.param, true);
+    this.expect(tt.parenR);
+    clause.guard = null;
+    clause.body = this.parseBlock();
+    node.handler = this.finishNode(clause, "CatchClause");
+  }
+  node.guardedHandlers = empty;
+  node.finalizer = this.eat(tt._finally) ? this.parseBlock() : null;
+  if (!node.handler && !node.finalizer)
+    this.raise(node.start, "Missing catch or finally clause");
+  return this.finishNode(node, "TryStatement");
+};
+
+pp.parseVarStatement = function(node, kind) {
+  this.next();
+  this.parseVar(node, false, kind);
+  this.semicolon();
+  return this.finishNode(node, "VariableDeclaration");
+};
+
+pp.parseWhileStatement = function(node) {
+  this.next();
+  node.test = this.parseParenExpression();
+  this.labels.push(loopLabel);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, "WhileStatement");
+};
+
+pp.parseWithStatement = function(node) {
+  if (this.strict) this.raise(this.start, "'with' in strict mode");
+  this.next();
+  node.object = this.parseParenExpression();
+  node.body = this.parseStatement(false);
+  return this.finishNode(node, "WithStatement");
+};
+
+pp.parseEmptyStatement = function(node) {
+  this.next();
+  return this.finishNode(node, "EmptyStatement");
+};
+
+pp.parseLabeledStatement = function(node, maybeName, expr) {
+  for (var i = 0; i < this.labels.length; ++i)
+    if (this.labels[i].name === maybeName) this.raise(expr.start, "Label '" + maybeName + "' is already declared");
+  var kind = this.type.isLoop ? "loop" : this.type === tt._switch ? "switch" : null;
+  this.labels.push({name: maybeName, kind: kind});
+  node.body = this.parseStatement(true);
+  this.labels.pop();
+  node.label = expr;
+  return this.finishNode(node, "LabeledStatement");
+};
+
+pp.parseExpressionStatement = function(node, expr) {
+  node.expression = expr;
+  this.semicolon();
+  return this.finishNode(node, "ExpressionStatement");
+};
+
+// Used for constructs like `switch` and `if` that insist on
+// parentheses around their expression.
+
+pp.parseParenExpression = function() {
+  this.expect(tt.parenL);
+  var val = this.parseExpression();
+  this.expect(tt.parenR);
+  return val;
+};
+
+// Parse a semicolon-enclosed block of statements, handling `"use
+// strict"` declarations when `allowStrict` is true (used for
+// function bodies).
+
+pp.parseBlock = function(allowStrict) {
+  var node = this.startNode(), first = true, oldStrict;
+  node.body = [];
+  this.expect(tt.braceL);
+  while (!this.eat(tt.braceR)) {
+    var stmt = this.parseStatement(true);
+    node.body.push(stmt);
+    if (first && allowStrict && this.isUseStrict(stmt)) {
+      oldStrict = this.strict;
+      this.setStrict(this.strict = true);
+    }
+    first = false;
+  }
+  if (oldStrict === false) this.setStrict(false);
+  return this.finishNode(node, "BlockStatement");
+};
+
+// Parse a regular `for` loop. The disambiguation code in
+// `parseStatement` will already have parsed the init statement or
+// expression.
+
+pp.parseFor = function(node, init) {
+  node.init = init;
+  this.expect(tt.semi);
+  node.test = this.type === tt.semi ? null : this.parseExpression();
+  this.expect(tt.semi);
+  node.update = this.type === tt.parenR ? null : this.parseExpression();
+  this.expect(tt.parenR);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, "ForStatement");
+};
+
+// Parse a `for`/`in` and `for`/`of` loop, which are almost
+// same from parser's perspective.
+
+pp.parseForIn = function(node, init) {
+  var type = this.type === tt._in ? "ForInStatement" : "ForOfStatement";
+  this.next();
+  node.left = init;
+  node.right = this.parseExpression();
+  this.expect(tt.parenR);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, type);
+};
+
+// Parse a list of variable declarations.
+
+pp.parseVar = function(node, noIn, kind) {
+  node.declarations = [];
+  node.kind = kind.keyword;
+  for (;;) {
+    var decl = this.startNode();
+    decl.id = this.parseBindingAtom();
+    this.checkLVal(decl.id, true);
+    if (this.eat(tt.eq)) {
+      decl.init = this.parseMaybeAssign(noIn);
+    } else if (kind === tt._const && !(this.type === tt._in || (this.options.ecmaVersion >= 6 && this.isContextual("of")))) {
+      this.unexpected();
+    } else if (decl.id.type != "Identifier") {
+      this.raise(this.lastTokEnd, "Complex binding patterns require an initialization value")
+    } else {
+      decl.init = null;
+    }
+    node.declarations.push(this.finishNode(decl, "VariableDeclarator"));
+    if (!this.eat(tt.comma)) break;
+  }
+  return node;
+};
+
+// ### 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 optional arguments are used to
+// forbid the `in` operator (in for loops initalization expressions)
+// and provide reference for storing '=' operator inside shorthand
+// property assignment in contexts where both object expression
+// and object pattern might appear (so it's possible to raise
+// delayed syntax error at correct position).
+
+pp.parseExpression = function(noIn, refShorthandDefaultPos) {
+  var start = this.currentPos();
+  var expr = this.parseMaybeAssign(noIn, refShorthandDefaultPos);
+  if (this.type === tt.comma) {
+    var node = this.startNodeAt(start);
+    node.expressions = [expr];
+    while (this.eat(tt.comma)) node.expressions.push(this.parseMaybeAssign(noIn, refShorthandDefaultPos));
+    return this.finishNode(node, "SequenceExpression");
+  }
+  return expr;
+};
+
+// Parse an assignment expression. This includes applications of
+// operators like `+=`.
+
+pp.parseMaybeAssign = function(noIn, refShorthandDefaultPos) {
+  if (this.type == tt._yield && this.inGenerator) return this.parseYield();
+
+  var failOnShorthandAssign;
+  if (!refShorthandDefaultPos) {
+    refShorthandDefaultPos = {start: 0};
+    failOnShorthandAssign = true;
+  } else {
+    failOnShorthandAssign = false;
+  }
+  var start = this.currentPos();
+  var left = this.parseMaybeConditional(noIn, refShorthandDefaultPos);
+  if (this.type.isAssign) {
+    var node = this.startNodeAt(start);
+    node.operator = this.value;
+    node.left = this.type === tt.eq ? this.toAssignable(left) : left;
+    refShorthandDefaultPos.start = 0; // reset because shorthand default was used correctly
+    this.checkLVal(left);
+    this.next();
+    node.right = this.parseMaybeAssign(noIn);
+    return this.finishNode(node, "AssignmentExpression");
+  } else if (failOnShorthandAssign && refShorthandDefaultPos.start) {
+    this.unexpected(refShorthandDefaultPos.start);
+  }
+  return left;
+};
+
+// Parse a ternary conditional (`?:`) operator.
+
+pp.parseMaybeConditional = function(noIn, refShorthandDefaultPos) {
+  var start = this.currentPos();
+  var expr = this.parseExprOps(noIn, refShorthandDefaultPos);
+  if (refShorthandDefaultPos && refShorthandDefaultPos.start) return expr;
+  if (this.eat(tt.question)) {
+    var node = this.startNodeAt(start);
+    node.test = expr;
+    node.consequent = this.parseMaybeAssign();
+    this.expect(tt.colon);
+    node.alternate = this.parseMaybeAssign(noIn);
+    return this.finishNode(node, "ConditionalExpression");
+  }
+  return expr;
+};
+
+// Start the precedence parser.
+
+pp.parseExprOps = function(noIn, refShorthandDefaultPos) {
+  var start = this.currentPos();
+  var expr = this.parseMaybeUnary(refShorthandDefaultPos);
+  if (refShorthandDefaultPos && refShorthandDefaultPos.start) return expr;
+  return this.parseExprOp(expr, start, -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.
+
+pp.parseExprOp = function(left, leftStart, minPrec, noIn) {
+  var prec = this.type.binop;
+  if (prec != null && (!noIn || this.type !== tt._in)) {
+    if (prec > minPrec) {
+      var node = this.startNodeAt(leftStart);
+      node.left = left;
+      node.operator = this.value;
+      var op = this.type;
+      this.next();
+      var start = this.currentPos();
+      node.right = this.parseExprOp(this.parseMaybeUnary(), start, prec, noIn);
+      this.finishNode(node, (op === tt.logicalOR || op === tt.logicalAND) ? "LogicalExpression" : "BinaryExpression");
+      return this.parseExprOp(node, leftStart, minPrec, noIn);
+    }
+  }
+  return left;
+};
+
+// Parse unary operators, both prefix and postfix.
+
+pp.parseMaybeUnary = function(refShorthandDefaultPos) {
+  if (this.type.prefix) {
+    var node = this.startNode(), update = this.type === tt.incDec;
+    node.operator = this.value;
+    node.prefix = true;
+    this.next();
+    node.argument = this.parseMaybeUnary();
+    if (refShorthandDefaultPos && refShorthandDefaultPos.start) this.unexpected(refShorthandDefaultPos.start);
+    if (update) this.checkLVal(node.argument);
+    else if (this.strict && node.operator === "delete" &&
+             node.argument.type === "Identifier")
+      this.raise(node.start, "Deleting local variable in strict mode");
+    return this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
+  }
+  var start = this.currentPos();
+  var expr = this.parseExprSubscripts(refShorthandDefaultPos);
+  if (refShorthandDefaultPos && refShorthandDefaultPos.start) return expr;
+  while (this.type.postfix && !this.canInsertSemicolon()) {
+    var node = this.startNodeAt(start);
+    node.operator = this.value;
+    node.prefix = false;
+    node.argument = expr;
+    this.checkLVal(expr);
+    this.next();
+    expr = this.finishNode(node, "UpdateExpression");
+  }
+  return expr;
+};
+
+// Parse call, dot, and `[]`-subscript expressions.
+
+pp.parseExprSubscripts = function(refShorthandDefaultPos) {
+  var start = this.currentPos();
+  var expr = this.parseExprAtom(refShorthandDefaultPos);
+  if (refShorthandDefaultPos && refShorthandDefaultPos.start) return expr;
+  return this.parseSubscripts(expr, start);
+};
+
+pp.parseSubscripts = function(base, start, noCalls) {
+  if (this.eat(tt.dot)) {
+    var node = this.startNodeAt(start);
+    node.object = base;
+    node.property = this.parseIdent(true);
+    node.computed = false;
+    return this.parseSubscripts(this.finishNode(node, "MemberExpression"), start, noCalls);
+  } else if (this.eat(tt.bracketL)) {
+    var node = this.startNodeAt(start);
+    node.object = base;
+    node.property = this.parseExpression();
+    node.computed = true;
+    this.expect(tt.bracketR);
+    return this.parseSubscripts(this.finishNode(node, "MemberExpression"), start, noCalls);
+  } else if (!noCalls && this.eat(tt.parenL)) {
+    var node = this.startNodeAt(start);
+    node.callee = base;
+    node.arguments = this.parseExprList(tt.parenR, false);
+    return this.parseSubscripts(this.finishNode(node, "CallExpression"), start, noCalls);
+  } else if (this.type === tt.backQuote) {
+    var node = this.startNodeAt(start);
+    node.tag = base;
+    node.quasi = this.parseTemplate();
+    return this.parseSubscripts(this.finishNode(node, "TaggedTemplateExpression"), start, 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 `{}`.
+
+pp.parseExprAtom = function(refShorthandDefaultPos) {
+  switch (this.type) {
+  case tt._this:
+  case tt._super:
+    var type = this.type === tt._this ? "ThisExpression" : "SuperExpression";
+    var node = this.startNode();
+    this.next();
+    return this.finishNode(node, type);
+
+  case tt._yield:
+    if (this.inGenerator) unexpected();
+
+  case tt.name:
+    var start = this.currentPos();
+    var id = this.parseIdent(this.type !== tt.name);
+    if (!this.canInsertSemicolon() && this.eat(tt.arrow)) {
+      return this.parseArrowExpression(this.startNodeAt(start), [id]);
+    }
+    return id;
+
+  case tt.regexp:
+    var value = this.value;
+    var node = this.parseLiteral(value.value);
+    node.regex = {pattern: value.pattern, flags: value.flags};
+    return node;
+
+  case tt.num: case tt.string:
+    return this.parseLiteral(this.value);
+
+  case tt._null: case tt._true: case tt._false:
+    var node = this.startNode();
+    node.value = this.type === tt._null ? null : this.type === tt._true;
+    node.raw = this.type.keyword;
+    this.next();
+    return this.finishNode(node, "Literal");
+
+  case tt.parenL:
+    return this.parseParenAndDistinguishExpression();
+
+  case tt.bracketL:
+    var node = this.startNode();
+    this.next();
+    // check whether this is array comprehension or regular array
+    if (this.options.ecmaVersion >= 7 && this.type === tt._for) {
+      return this.parseComprehension(node, false);
+    }
+    node.elements = this.parseExprList(tt.bracketR, true, true, refShorthandDefaultPos);
+    return this.finishNode(node, "ArrayExpression");
+
+  case tt.braceL:
+    return this.parseObj(false, refShorthandDefaultPos);
+
+  case tt._function:
+    var node = this.startNode();
+    this.next();
+    return this.parseFunction(node, false);
+
+  case tt._class:
+    return this.parseClass(this.startNode(), false);
+
+  case tt._new:
+    return this.parseNew();
+
+  case tt.backQuote:
+    return this.parseTemplate();
+
+  default:
+    this.unexpected();
+  }
+};
+
+pp.parseLiteral = function(value) {
+  var node = this.startNode();
+  node.value = value;
+  node.raw = this.input.slice(this.start, this.end);
+  this.next();
+  return this.finishNode(node, "Literal");
+};
+
+pp.parseParenAndDistinguishExpression = function() {
+  var start = this.currentPos(), val;
+  if (this.options.ecmaVersion >= 6) {
+    this.next();
+
+    if (this.options.ecmaVersion >= 7 && this.type === tt._for) {
+      return this.parseComprehension(this.startNodeAt(start), true);
+    }
+
+    var innerStart = this.currentPos(), exprList = [], first = true;
+    var refShorthandDefaultPos = {start: 0}, spreadStart, innerParenStart;
+    while (this.type !== tt.parenR) {
+      first ? first = false : this.expect(tt.comma);
+      if (this.type === tt.ellipsis) {
+        spreadStart = this.start;
+        exprList.push(this.parseRest());
+        break;
+      } else {
+        if (this.type === tt.parenL && !innerParenStart) {
+          innerParenStart = this.start;
+        }
+        exprList.push(this.parseMaybeAssign(false, refShorthandDefaultPos));
+      }
+    }
+    var innerEnd = this.currentPos();
+    this.expect(tt.parenR);
+
+    if (!this.canInsertSemicolon() && this.eat(tt.arrow)) {
+      if (innerParenStart) this.unexpected(innerParenStart);
+      return this.parseArrowExpression(this.startNodeAt(start), exprList);
+    }
+
+    if (!exprList.length) this.unexpected(this.lastTokStart);
+    if (spreadStart) this.unexpected(spreadStart);
+    if (refShorthandDefaultPos.start) this.unexpected(refShorthandDefaultPos.start);
+
+    if (exprList.length > 1) {
+      val = this.startNodeAt(innerStart);
+      val.expressions = exprList;
+      this.finishNodeAt(val, "SequenceExpression", innerEnd);
+    } else {
+      val = exprList[0];
+    }
+  } else {
+    val = this.parseParenExpression();
+  }
+
+  if (this.options.preserveParens) {
+    var par = this.startNodeAt(start);
+    par.expression = val;
+    return this.finishNode(par, "ParenthesizedExpression");
+  } else {
+    return val;
+  }
+};
+
+// 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
+
+pp.parseNew = function() {
+  var node = this.startNode();
+  this.next();
+  var start = this.currentPos();
+  node.callee = this.parseSubscripts(this.parseExprAtom(), start, true);
+  if (this.eat(tt.parenL)) node.arguments = this.parseExprList(tt.parenR, false);
+  else node.arguments = empty;
+  return this.finishNode(node, "NewExpression");
+};
+
+// Parse template expression.
+
+pp.parseTemplateElement = function() {
+  var elem = this.startNode();
+  elem.value = {
+    raw: this.input.slice(this.start, this.end),
+    cooked: this.value
+  };
+  this.next();
+  elem.tail = this.type === tt.backQuote;
+  return this.finishNode(elem, "TemplateElement");
+};
+
+pp.parseTemplate = function() {
+  var node = this.startNode();
+  this.next();
+  node.expressions = [];
+  var curElt = this.parseTemplateElement();
+  node.quasis = [curElt];
+  while (!curElt.tail) {
+    this.expect(tt.dollarBraceL);
+    node.expressions.push(this.parseExpression());
+    this.expect(tt.braceR);
+    node.quasis.push(curElt = this.parseTemplateElement());
+  }
+  this.next();
+  return this.finishNode(node, "TemplateLiteral");
+};
+
+// Parse an object literal or binding pattern.
+
+pp.parseObj = function(isPattern, refShorthandDefaultPos) {
+  var node = this.startNode(), first = true, propHash = {};
+  node.properties = [];
+  this.next();
+  while (!this.eat(tt.braceR)) {
+    if (!first) {
+      this.expect(tt.comma);
+      if (this.afterTrailingComma(tt.braceR)) break;
+    } else first = false;
+
+    var prop = this.startNode(), isGenerator, start;
+    if (this.options.ecmaVersion >= 6) {
+      prop.method = false;
+      prop.shorthand = false;
+      if (isPattern || refShorthandDefaultPos)
+        start = this.currentPos();
+      if (!isPattern)
+        isGenerator = this.eat(tt.star);
+    }
+    this.parsePropertyName(prop);
+    if (this.eat(tt.colon)) {
+      prop.value = isPattern ? this.parseMaybeDefault() : this.parseMaybeAssign(false, refShorthandDefaultPos);
+      prop.kind = "init";
+    } else if (this.options.ecmaVersion >= 6 && this.type === tt.parenL) {
+      if (isPattern) this.unexpected();
+      prop.kind = "init";
+      prop.method = true;
+      prop.value = this.parseMethod(isGenerator);
+    } else if (this.options.ecmaVersion >= 5 && !prop.computed && prop.key.type === "Identifier" &&
+               (prop.key.name === "get" || prop.key.name === "set") &&
+               (this.type != tt.comma && this.type != tt.braceR)) {
+      if (isGenerator || isPattern) this.unexpected();
+      prop.kind = prop.key.name;
+      this.parsePropertyName(prop);
+      prop.value = this.parseMethod(false);
+    } else if (this.options.ecmaVersion >= 6 && !prop.computed && prop.key.type === "Identifier") {
+      prop.kind = "init";
+      if (isPattern) {
+        if (this.isKeyword(prop.key.name) ||
+            (this.strict && (isStrictBadIdWord(prop.key.name) || isStrictReservedWord(prop.key.name))) ||
+            (!this.options.allowReserved && this.isReservedWord(prop.key.name)))
+          this.raise(prop.key.start, "Binding " + prop.key.name);
+        prop.value = this.parseMaybeDefault(start, prop.key);
+      } else if (this.type === tt.eq && refShorthandDefaultPos) {
+        if (!refShorthandDefaultPos.start)
+          refShorthandDefaultPos.start = this.start;
+        prop.value = this.parseMaybeDefault(start, prop.key);
+      } else {
+        prop.value = prop.key;
+      }
+      prop.shorthand = true;
+    } else this.unexpected();
+
+    this.checkPropClash(prop, propHash);
+    node.properties.push(this.finishNode(prop, "Property"));
+  }
+  return this.finishNode(node, isPattern ? "ObjectPattern" : "ObjectExpression");
+};
+
+pp.parsePropertyName = function(prop) {
+  if (this.options.ecmaVersion >= 6) {
+    if (this.eat(tt.bracketL)) {
+      prop.computed = true;
+      prop.key = this.parseExpression();
+      this.expect(tt.bracketR);
+      return;
+    } else {
+      prop.computed = false;
+    }
+  }
+  prop.key = (this.type === tt.num || this.type === tt.string) ? this.parseExprAtom() : this.parseIdent(true);
+};
+
+// Initialize empty function node.
+
+pp.initFunction = function(node) {
+  node.id = null;
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = false;
+    node.expression = false;
+  }
+};
+
+// Parse a function declaration or literal (depending on the
+// `isStatement` parameter).
+
+pp.parseFunction = function(node, isStatement, allowExpressionBody) {
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = this.eat(tt.star);
+  }
+  if (isStatement || this.type === tt.name) {
+    node.id = this.parseIdent();
+  }
+  this.expect(tt.parenL);
+  node.params = this.parseBindingList(tt.parenR, false, false);
+  this.parseFunctionBody(node, allowExpressionBody);
+  return this.finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression");
+};
+
+// Parse object or class method.
+
+pp.parseMethod = function(isGenerator) {
+  var node = this.startNode();
+  this.initFunction(node);
+  this.expect(tt.parenL);
+  node.params = this.parseBindingList(tt.parenR, false, false);
+  var allowExpressionBody;
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = isGenerator;
+    allowExpressionBody = true;
+  } else {
+    allowExpressionBody = false;
+  }
+  this.parseFunctionBody(node, allowExpressionBody);
+  return this.finishNode(node, "FunctionExpression");
+};
+
+// Parse arrow function expression with given parameters.
+
+pp.parseArrowExpression = function(node, params) {
+  this.initFunction(node);
+  node.params = this.toAssignableList(params, true);
+  this.parseFunctionBody(node, true);
+  return this.finishNode(node, "ArrowFunctionExpression");
+};
+
+// Parse function body and check parameters.
+
+pp.parseFunctionBody = function(node, allowExpression) {
+  var isExpression = allowExpression && this.type !== tt.braceL;
+
+  if (isExpression) {
+    node.body = this.parseMaybeAssign();
+    node.expression = true;
+  } else {
+    // Start a new scope with regard to labels and the `inFunction`
+    // flag (restore them to their old value afterwards).
+    var oldInFunc = this.inFunction, oldInGen = this.inGenerator, oldLabels = this.labels;
+    this.inFunction = true; this.inGenerator = node.generator; this.labels = [];
+    node.body = this.parseBlock(true);
+    node.expression = false;
+    this.inFunction = oldInFunc; this.inGenerator = oldInGen; this.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 (this.strict || !isExpression && node.body.body.length && this.isUseStrict(node.body.body[0])) {
+    var nameHash = {}, oldStrict = this.strict;
+    this.strict = true;
+    if (node.id)
+      this.checkLVal(node.id, true);
+    for (var i = 0; i < node.params.length; i++)
+      this.checkLVal(node.params[i], true, nameHash);
+    this.strict = oldStrict;
+  }
+};
+
+// Parse a class declaration or literal (depending on the
+// `isStatement` parameter).
+
+pp.parseClass = function(node, isStatement) {
+  this.next();
+  node.id = this.type === tt.name ? this.parseIdent() : isStatement ? this.unexpected() : null;
+  node.superClass = this.eat(tt._extends) ? this.parseExprSubscripts() : null;
+  var classBody = this.startNode();
+  classBody.body = [];
+  this.expect(tt.braceL);
+  while (!this.eat(tt.braceR)) {
+    if (this.eat(tt.semi)) continue;
+    var method = this.startNode();
+    var isGenerator = this.eat(tt.star);
+    this.parsePropertyName(method);
+    if (this.type !== tt.parenL && !method.computed && method.key.type === "Identifier" &&
+        method.key.name === "static") {
+      if (isGenerator) this.unexpected();
+      method['static'] = true;
+      isGenerator = this.eat(tt.star);
+      this.parsePropertyName(method);
+    } else {
+      method['static'] = false;
+    }
+    method.kind = "method";
+    if (!method.computed && !isGenerator) {
+      if (method.key.type === "Identifier") {
+        if (this.type !== tt.parenL && (method.key.name === "get" || method.key.name === "set")) {
+          method.kind = method.key.name;
+          this.parsePropertyName(method);
+        } else if (!method['static'] && method.key.name === "constructor") {
+          method.kind = "constructor";
+        }
+      } else if (!method['static'] && method.key.type === "Literal" && method.key.value === "constructor") {
+        method.kind = "constructor";
+      }
+    }
+    method.value = this.parseMethod(isGenerator);
+    classBody.body.push(this.finishNode(method, "MethodDefinition"));
+  }
+  node.body = this.finishNode(classBody, "ClassBody");
+  return this.finishNode(node, isStatement ? "ClassDeclaration" : "ClassExpression");
+};
+
+// 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).
+
+pp.parseExprList = function(close, allowTrailingComma, allowEmpty, refShorthandDefaultPos) {
+  var elts = [], first = true;
+  while (!this.eat(close)) {
+    if (!first) {
+      this.expect(tt.comma);
+      if (allowTrailingComma && this.afterTrailingComma(close)) break;
+    } else first = false;
+
+    if (allowEmpty && this.type === tt.comma) {
+      elts.push(null);
+    } else {
+      if (this.type === tt.ellipsis)
+        elts.push(this.parseSpread(refShorthandDefaultPos));
+      else
+        elts.push(this.parseMaybeAssign(false, refShorthandDefaultPos));
+    }
+  }
+  return elts;
+};
+
+// Parse the next token as an identifier. If `liberal` is true (used
+// when parsing properties), it will also convert keywords into
+// identifiers.
+
+pp.parseIdent = function(liberal) {
+  var node = this.startNode();
+  if (liberal && this.options.allowReserved == "never") liberal = false;
+  if (this.type === tt.name) {
+    if (!liberal &&
+        ((!this.options.allowReserved && this.isReservedWord(this.value)) ||
+         (this.strict && isStrictReservedWord(this.value)) &&
+         (this.options.ecmaVersion >= 6 || 
+          this.input.slice(this.start, this.end).indexOf("\\") == -1)))
+      this.raise(this.start, "The keyword '" + this.value + "' is reserved");
+    node.name = this.value;
+  } else if (liberal && this.type.keyword) {
+    node.name = this.type.keyword;
+  } else {
+    this.unexpected();
+  }
+  this.next();
+  return this.finishNode(node, "Identifier");
+};
+
+// Parses module export declaration.
+
+pp.parseExport = function(node) {
+  this.next();
+  // export * from '...';
+  if (this.eat(tt.star)) {
+    this.expectContextual("from");
+    node.source = this.type === tt.string ? this.parseExprAtom() : this.unexpected();
+    this.semicolon();
+    return this.finishNode(node, "ExportAllDeclaration");
+  }
+  if (this.eat(tt._default)) { // export default ...;
+    var expr = this.parseMaybeAssign();
+    if (expr.id) {
+      switch (expr.type) {
+      case "FunctionExpression": expr.type = "FunctionDeclaration"; break;
+      case "ClassExpression": expr.type = "ClassDeclaration"; break;
+      }
+    }
+    node.declaration = expr;
+    this.semicolon();
+    return this.finishNode(node, "ExportDefaultDeclaration");
+  }
+  // export var|const|let|function|class ...;
+  if (this.type.keyword) {
+    node.declaration = this.parseStatement(true);
+    node.specifiers = [];
+    node.source = null;
+  } else { // export { x, y as z } [from '...'];
+    node.declaration = null;
+    node.specifiers = this.parseExportSpecifiers();
+    if (this.eatContextual("from")) {
+      node.source = this.type === tt.string ? this.parseExprAtom() : this.unexpected();
+    } else {
+      node.source = null;
+    }
+    this.semicolon();
+  }
+  return this.finishNode(node, "ExportNamedDeclaration");
+};
+
+// Parses a comma-separated list of module exports.
+
+pp.parseExportSpecifiers = function() {
+  var nodes = [], first = true;
+  // export { x, y as z } [from '...']
+  this.expect(tt.braceL);
+  while (!this.eat(tt.braceR)) {
+    if (!first) {
+      this.expect(tt.comma);
+      if (this.afterTrailingComma(tt.braceR)) break;
+    } else first = false;
+
+    var node = this.startNode();
+    node.local = this.parseIdent(this.type === tt._default);
+    node.exported = this.eatContextual("as") ? this.parseIdent(true) : node.local;
+    nodes.push(this.finishNode(node, "ExportSpecifier"));
+  }
+  return nodes;
+};
+
+// Parses import declaration.
+
+pp.parseImport = function(node) {
+  this.next();
+  // import '...';
+  if (this.type === tt.string) {
+    node.specifiers = empty;
+    node.source = this.parseExprAtom();
+    node.kind = "";
+  } else {
+    node.specifiers = this.parseImportSpecifiers();
+    this.expectContextual("from");
+    node.source = this.type === tt.string ? this.parseExprAtom() : this.unexpected();
+  }
+  this.semicolon();
+  return this.finishNode(node, "ImportDeclaration");
+};
+
+// Parses a comma-separated list of module imports.
+
+pp.parseImportSpecifiers = function() {
+  var nodes = [], first = true;
+  if (this.type === tt.name) {
+    // import defaultObj, { x, y as z } from '...'
+    var node = this.startNode();
+    node.local = this.parseIdent();
+    this.checkLVal(node.local, true);
+    nodes.push(this.finishNode(node, "ImportDefaultSpecifier"));
+    if (!this.eat(tt.comma)) return nodes;
+  }
+  if (this.type === tt.star) {
+    var node = this.startNode();
+    this.next();
+    this.expectContextual("as");
+    node.local = this.parseIdent();
+    this.checkLVal(node.local, true);
+    nodes.push(this.finishNode(node, "ImportNamespaceSpecifier"));
+    return nodes;
+  }
+  this.expect(tt.braceL);
+  while (!this.eat(tt.braceR)) {
+    if (!first) {
+      this.expect(tt.comma);
+      if (this.afterTrailingComma(tt.braceR)) break;
+    } else first = false;
+
+    var node = this.startNode();
+    node.imported = this.parseIdent(true);
+    node.local = this.eatContextual("as") ? this.parseIdent() : node.imported;
+    this.checkLVal(node.local, true);
+    nodes.push(this.finishNode(node, "ImportSpecifier"));
+  }
+  return nodes;
+};
+
+// Parses yield expression inside generator.
+
+pp.parseYield = function() {
+  var node = this.startNode();
+  this.next();
+  if (this.type == tt.semi || this.canInsertSemicolon() || (this.type != tt.star && !this.type.startsExpr)) {
+    node.delegate = false;
+    node.argument = null;
+  } else {
+    node.delegate = this.eat(tt.star);
+    node.argument = this.parseMaybeAssign();
+  }
+  return this.finishNode(node, "YieldExpression");
+};
+
+// Parses array and generator comprehensions.
+
+pp.parseComprehension = function(node, isGenerator) {
+  node.blocks = [];
+  while (this.type === tt._for) {
+    var block = this.startNode();
+    this.next();
+    this.expect(tt.parenL);
+    block.left = this.parseBindingAtom();
+    this.checkLVal(block.left, true);
+    this.expectContextual("of");
+    block.right = this.parseExpression();
+    this.expect(tt.parenR);
+    node.blocks.push(this.finishNode(block, "ComprehensionBlock"));
+  }
+  node.filter = this.eat(tt._if) ? this.parseParenExpression() : null;
+  node.body = this.parseExpression();
+  this.expect(isGenerator ? tt.parenR : tt.bracketR);
+  node.generator = isGenerator;
+  return this.finishNode(node, "ComprehensionExpression");
+};
diff --git a/src/tokentype.js b/src/tokentype.js
new file mode 100644
index 0000000000..5f2bdb2380
--- /dev/null
+++ b/src/tokentype.js
@@ -0,0 +1,142 @@
+// ## 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.
+
+// 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.
+
+export class TokenType {
+  constructor(label, conf = {}) {
+    this.label = label
+    this.keyword = conf.keyword
+    this.beforeExpr = !!conf.beforeExpr
+    this.startsExpr = !!conf.startsExpr
+    this.isLoop = !!conf.isLoop
+    this.isAssign = !!conf.isAssign
+    this.prefix = !!conf.prefix
+    this.postfix = !!conf.postfix
+    this.binop = conf.binop || null
+    this.updateContext = null
+  }
+}
+
+function binop(name, prec) {
+  return new TokenType(name, {beforeExpr: true, binop: prec})
+}
+const beforeExpr = {beforeExpr: true}, startsExpr = {startsExpr: true}
+
+export const types = {
+  num: new TokenType("num", startsExpr),
+  regexp: new TokenType("regexp", startsExpr),
+  string: new TokenType("string", startsExpr),
+  name: new TokenType("name", startsExpr),
+  eof: new TokenType("eof"),
+
+  // Punctuation token types.
+  bracketL: new TokenType("[", {beforeExpr: true, startsExpr: true}),
+  bracketR: new TokenType("]"),
+  braceL: new TokenType("{", {beforeExpr: true, startsExpr: true}),
+  braceR: new TokenType("}"),
+  parenL: new TokenType("(", {beforeExpr: true, startsExpr: true}),
+  parenR: new TokenType(")"),
+  comma: new TokenType(",", beforeExpr),
+  semi: new TokenType(";", beforeExpr),
+  colon: new TokenType(":", beforeExpr),
+  dot: new TokenType("."),
+  question: new TokenType("?", beforeExpr),
+  arrow: new TokenType("=>", beforeExpr),
+  template: new TokenType("template"),
+  ellipsis: new TokenType("...", beforeExpr),
+  backQuote: new TokenType("`", startsExpr),
+  dollarBraceL: new TokenType("${", {beforeExpr: true, startsExpr: 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.
+  //
+  // `isAssign` marks all of `=`, `+=`, `-=` etcetera, which act as
+  // binary operators with a very low precedence, that should result
+  // in AssignmentExpression nodes.
+
+  eq: new TokenType("=", {beforeExpr: true, isAssign: true}),
+  assign: new TokenType("_=", {beforeExpr: true, isAssign: true}),
+  incDec: new TokenType("++/--", {prefix: true, postfix: true, startsExpr: true}),
+  prefix: new TokenType("prefix", {beforeExpr: true, prefix: true, startsExpr: true}),
+  logicalOR: binop("||", 1),
+  logicalAND: binop("&&", 2),
+  bitwiseOR: binop("|", 3),
+  bitwiseXOR: binop("^", 4),
+  bitwiseAND: binop("&", 5),
+  equality: binop("==/!=", 6),
+  relational: binop("</>", 7),
+  bitShift: binop("<</>>", 8),
+  plusMin: new TokenType("+/-", {beforeExpr: true, binop: 9, prefix: true, startsExpr: true}),
+  modulo: binop("%", 10),
+  star: binop("*", 10),
+  slash: binop("/", 10)
+}
+
+// Map keyword names to token types.
+
+export const keywords = {}
+
+// Succinct definitions of keyword token types
+function kw(name, options = {}) {
+  options.keyword = name
+  keywords[name] = types["_" + name] = new TokenType(name, options)
+}
+
+kw("break")
+kw("case", beforeExpr)
+kw("catch")
+kw("continue")
+kw("debugger")
+kw("default")
+kw("do", {isLoop: true})
+kw("else", beforeExpr)
+kw("finally")
+kw("for", {isLoop: true})
+kw("function")
+kw("if")
+kw("return", beforeExpr)
+kw("switch")
+kw("throw", beforeExpr)
+kw("try")
+kw("var")
+kw("let")
+kw("const")
+kw("while", {isLoop: true})
+kw("with")
+kw("new", {beforeExpr: true, startsExpr: true})
+kw("this", startsExpr)
+kw("super", startsExpr)
+kw("class")
+kw("extends", beforeExpr)
+kw("export")
+kw("import")
+kw("yield", {beforeExpr: true, startsExpr: true})
+kw("null", startsExpr)
+kw("true", startsExpr)
+kw("false", startsExpr)
+kw("in", {beforeExpr: true, binop: 7})
+kw("instanceof", {beforeExpr: true, binop: 7})
+kw("typeof", {beforeExpr: true, prefix: true, startsExpr: true})
+kw("void", {beforeExpr: true, prefix: true, startsExpr: true})
+kw("delete", {beforeExpr: true, prefix: true, startsExpr: true})
diff --git a/src/util.js b/src/util.js
new file mode 100644
index 0000000000..3517f8d212
--- /dev/null
+++ b/src/util.js
@@ -0,0 +1,9 @@
+export function isArray(obj) {
+  return Object.prototype.toString.call(obj) === "[object Array]"
+}
+
+// Checks if an object has a property.
+
+export function has(obj, propName) {
+  return Object.prototype.hasOwnProperty.call(obj, propName)
+}