From f46c401a5a356235a9364afa1521fe4426868d6e Mon Sep 17 00:00:00 2001
From: Alan Schmitt <alan.schmitt@polytechnique.org>
Date: Wed, 25 Nov 2015 16:45:00 +0100
Subject: [PATCH] typechecking

---
 generator/node_modules/.bin/esparse           |    1 +
 generator/node_modules/.bin/esvalidate        |    1 +
 generator/node_modules/esprima/ChangeLog      |  151 +
 generator/node_modules/esprima/LICENSE.BSD    |   21 +
 generator/node_modules/esprima/README.md      |   27 +
 generator/node_modules/esprima/bin/esparse.js |  126 +
 .../node_modules/esprima/bin/esvalidate.js    |  199 +
 generator/node_modules/esprima/esprima.js     | 5661 +++++++++++++++++
 generator/node_modules/esprima/package.json   |  109 +
 generator/tests/js/calcunlog.js               |   74 +
 generator/tests/js/letunlog.js                |   34 +
 generator/tests/js/mylistunlog.js             |  163 +
 generator/tests/js/recordsunlog.js            |    7 +
 generator/tests/js/stackunlog.js              |   24 +
 14 files changed, 6598 insertions(+)
 create mode 120000 generator/node_modules/.bin/esparse
 create mode 120000 generator/node_modules/.bin/esvalidate
 create mode 100644 generator/node_modules/esprima/ChangeLog
 create mode 100644 generator/node_modules/esprima/LICENSE.BSD
 create mode 100644 generator/node_modules/esprima/README.md
 create mode 100755 generator/node_modules/esprima/bin/esparse.js
 create mode 100755 generator/node_modules/esprima/bin/esvalidate.js
 create mode 100644 generator/node_modules/esprima/esprima.js
 create mode 100644 generator/node_modules/esprima/package.json
 create mode 100644 generator/tests/js/calcunlog.js
 create mode 100644 generator/tests/js/letunlog.js
 create mode 100644 generator/tests/js/mylistunlog.js
 create mode 100644 generator/tests/js/recordsunlog.js
 create mode 100644 generator/tests/js/stackunlog.js

diff --git a/generator/node_modules/.bin/esparse b/generator/node_modules/.bin/esparse
new file mode 120000
index 0000000..7423b18
--- /dev/null
+++ b/generator/node_modules/.bin/esparse
@@ -0,0 +1 @@
+../esprima/bin/esparse.js
\ No newline at end of file
diff --git a/generator/node_modules/.bin/esvalidate b/generator/node_modules/.bin/esvalidate
new file mode 120000
index 0000000..16069ef
--- /dev/null
+++ b/generator/node_modules/.bin/esvalidate
@@ -0,0 +1 @@
+../esprima/bin/esvalidate.js
\ No newline at end of file
diff --git a/generator/node_modules/esprima/ChangeLog b/generator/node_modules/esprima/ChangeLog
new file mode 100644
index 0000000..6a9df22
--- /dev/null
+++ b/generator/node_modules/esprima/ChangeLog
@@ -0,0 +1,151 @@
+2015-09-01: Version 2.6.0
+
+      * Properly allow or prohibit `let` in a binding identifier/pattern (issue 1048, 1098)
+      * Add sourceType field for Program node (issue 1159)
+      * Ensure that strict mode reserved word binding throw an error (issue 1171)
+      * Run the test suite with Node.js and IE 11 on Windows (issue 1294)
+      * Allow binding pattern with no initializer in a for statement (issue 1301)
+
+2015-07-31: Version 2.5.0
+
+      * Run the test suite in a browser environment (issue 1004)
+      * Ensure a comma between imported default binding and named imports (issue 1046)
+      * Distinguish `yield` as a keyword vs an identifier (issue 1186)
+      * Support ES6 meta property `new.target` (issue 1203)
+      * Fix the syntax node for yield with expression (issue 1223)
+      * Fix the check of duplicated proto in property names (issue 1225)
+      * Fix ES6 Unicode escape in identifier name (issue 1229)
+      * Support ES6 IdentifierStart and IdentifierPart (issue 1232)
+      * Treat await as a reserved word when parsing as a module (issue 1234)
+      * Recognize identifier characters from Unicode SMP (issue 1244)
+      * Ensure that export and import can be followed by a comma (issue 1250)
+      * Fix yield operator precedence (issue 1262)
+
+2015-07-01: Version 2.4.1
+
+      * Fix some cases of comment attachment (issue 1071, 1175)
+      * Fix the handling of destructuring in function arguments (issue 1193)
+      * Fix invalid ranges in assignment expression (issue 1201)
+
+2015-06-26: Version 2.4.0
+
+      * Support ES6 for-of iteration (issue 1047)
+      * Support ES6 spread arguments (issue 1169)
+      * Minimize npm payload (issue 1191)
+
+2015-06-16: Version 2.3.0
+
+      * Support ES6 generator (issue 1033)
+      * Improve parsing of regular expressions with `u` flag (issue 1179)
+
+2015-04-17: Version 2.2.0
+
+      * Support ES6 import and export declarations (issue 1000)
+      * Fix line terminator before arrow not recognized as error (issue 1009)
+      * Support ES6 destructuring (issue 1045)
+      * Support ES6 template literal (issue 1074)
+      * Fix the handling of invalid/incomplete string escape sequences (issue 1106)
+      * Fix ES3 static member access restriction (issue 1120)
+      * Support for `super` in ES6 class (issue 1147)
+
+2015-03-09: Version 2.1.0
+
+      * Support ES6 class (issue 1001)
+      * Support ES6 rest parameter (issue 1011)
+      * Expand the location of property getter, setter, and methods (issue 1029)
+      * Enable TryStatement transition to a single handler (issue 1031)
+      * Support ES6 computed property name (issue 1037)
+      * Tolerate unclosed block comment (issue 1041)
+      * Support ES6 lexical declaration (issue 1065)
+
+2015-02-06: Version 2.0.0
+
+      * Support ES6 arrow function (issue 517)
+      * Support ES6 Unicode code point escape (issue 521)
+      * Improve the speed and accuracy of comment attachment (issue 522)
+      * Support ES6 default parameter (issue 519)
+      * Support ES6 regular expression flags (issue 557)
+      * Fix scanning of implicit octal literals (issue 565)
+      * Fix the handling of automatic semicolon insertion (issue 574)
+      * Support ES6 method definition (issue 620)
+      * Support ES6 octal integer literal (issue 621)
+      * Support ES6 binary integer literal (issue 622)
+      * Support ES6 object literal property value shorthand (issue 624)
+
+2015-03-03: Version 1.2.5
+
+      * Fix scanning of implicit octal literals (issue 565)
+
+2015-02-05: Version 1.2.4
+
+      * Fix parsing of LeftHandSideExpression in ForInStatement (issue 560)
+      * Fix the handling of automatic semicolon insertion (issue 574)
+
+2015-01-18: Version 1.2.3
+
+      * Fix division by this (issue 616)
+
+2014-05-18: Version 1.2.2
+
+      * Fix duplicated tokens when collecting comments (issue 537)
+
+2014-05-04: Version 1.2.1
+
+      * Ensure that Program node may still have leading comments (issue 536)
+
+2014-04-29: Version 1.2.0
+
+      * Fix semicolon handling for expression statement (issue 462, 533)
+      * Disallow escaped characters in regular expression flags (issue 503)
+      * Performance improvement for location tracking (issue 520)
+      * Improve the speed of comment attachment (issue 522)
+
+2014-03-26: Version 1.1.1
+
+      * Fix token handling of forward slash after an array literal (issue 512)
+
+2014-03-23: Version 1.1.0
+
+      * Optionally attach comments to the owning syntax nodes (issue 197)
+      * Simplify binary parsing with stack-based shift reduce (issue 352)
+      * Always include the raw source of literals (issue 376)
+      * Add optional input source information (issue 386)
+      * Tokenizer API for pure lexical scanning (issue 398)
+      * Improve the web site and its online demos (issue 337, 400, 404)
+      * Performance improvement for location tracking (issue 417, 424)
+      * Support HTML comment syntax (issue 451)
+      * Drop support for legacy browsers (issue 474)
+
+2013-08-27: Version 1.0.4
+
+      * Minimize the payload for packages (issue 362)
+      * Fix missing cases on an empty switch statement (issue 436)
+      * Support escaped ] in regexp literal character classes (issue 442)
+      * Tolerate invalid left-hand side expression (issue 130)
+
+2013-05-17: Version 1.0.3
+
+      * Variable declaration needs at least one declarator (issue 391)
+      * Fix benchmark's variance unit conversion (issue 397)
+      * IE < 9: \v should be treated as vertical tab (issue 405)
+      * Unary expressions should always have prefix: true (issue 418)
+      * Catch clause should only accept an identifier (issue 423)
+      * Tolerate setters without parameter (issue 426)
+
+2012-11-02: Version 1.0.2
+
+    Improvement:
+
+      * Fix esvalidate JUnit output upon a syntax error (issue 374)
+
+2012-10-28: Version 1.0.1
+
+    Improvements:
+
+      * esvalidate understands shebang in a Unix shell script (issue 361)
+      * esvalidate treats fatal parsing failure as an error (issue 361)
+      * Reduce Node.js package via .npmignore (issue 362)
+
+2012-10-22: Version 1.0.0
+
+    Initial release.
diff --git a/generator/node_modules/esprima/LICENSE.BSD b/generator/node_modules/esprima/LICENSE.BSD
new file mode 100644
index 0000000..17557ec
--- /dev/null
+++ b/generator/node_modules/esprima/LICENSE.BSD
@@ -0,0 +1,21 @@
+Copyright (c) jQuery Foundation, Inc. and Contributors, All Rights Reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+  * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/generator/node_modules/esprima/README.md b/generator/node_modules/esprima/README.md
new file mode 100644
index 0000000..77619c3
--- /dev/null
+++ b/generator/node_modules/esprima/README.md
@@ -0,0 +1,27 @@
+[![NPM version](https://img.shields.io/npm/v/esprima.svg)](https://www.npmjs.com/package/esprima)
+[![npm download](https://img.shields.io/npm/dm/esprima.svg)](https://www.npmjs.com/package/esprima)
+[![Build Status](https://img.shields.io/travis/jquery/esprima/master.svg)](https://travis-ci.org/jquery/esprima)
+[![Coverage Status](https://img.shields.io/codecov/c/github/jquery/esprima/master.svg)](https://codecov.io/github/jquery/esprima)
+
+**Esprima** ([esprima.org](http://esprima.org), BSD license) is a high performance,
+standard-compliant [ECMAScript](http://www.ecma-international.org/publications/standards/Ecma-262.htm)
+parser written in ECMAScript (also popularly known as
+[JavaScript](https://en.wikipedia.org/wiki/JavaScript)).
+Esprima is created and maintained by [Ariya Hidayat](https://twitter.com/ariyahidayat),
+with the help of [many contributors](https://github.com/jquery/esprima/contributors).
+
+### Features
+
+- Full support for ECMAScript 6 ([ECMA-262](http://www.ecma-international.org/publications/standards/Ecma-262.htm))
+- Sensible [syntax tree format](https://github.com/estree/estree/blob/master/spec.md) as standardized by [ESTree project](https://github.com/estree/estree)
+- Optional tracking of syntax node location (index-based and line-column)
+- Heavily tested (~1200 [unit tests](https://github.com/jquery/esprima/tree/master/test/fixtures) with [full code coverage](https://codecov.io/github/jquery/esprima))
+
+Esprima serves as a **building block** for some JavaScript
+language tools, from [code instrumentation](http://esprima.org/demo/functiontrace.html)
+to [editor autocompletion](http://esprima.org/demo/autocomplete.html).
+
+Esprima runs on many popular web browsers, as well as other ECMAScript platforms such as
+[Rhino](http://www.mozilla.org/rhino), [Nashorn](http://openjdk.java.net/projects/nashorn/), and [Node.js](https://npmjs.org/package/esprima).
+
+For more information, check the web site [esprima.org](http://esprima.org).
diff --git a/generator/node_modules/esprima/bin/esparse.js b/generator/node_modules/esprima/bin/esparse.js
new file mode 100755
index 0000000..98bdbf4
--- /dev/null
+++ b/generator/node_modules/esprima/bin/esparse.js
@@ -0,0 +1,126 @@
+#!/usr/bin/env node
+/*
+  Copyright (c) jQuery Foundation, Inc. and Contributors, All Rights Reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/*jslint sloppy:true node:true rhino:true */
+
+var fs, esprima, fname, content, options, syntax;
+
+if (typeof require === 'function') {
+    fs = require('fs');
+    esprima = require('esprima');
+} else if (typeof load === 'function') {
+    try {
+        load('esprima.js');
+    } catch (e) {
+        load('../esprima.js');
+    }
+}
+
+// Shims to Node.js objects when running under Rhino.
+if (typeof console === 'undefined' && typeof process === 'undefined') {
+    console = { log: print };
+    fs = { readFileSync: readFile };
+    process = { argv: arguments, exit: quit };
+    process.argv.unshift('esparse.js');
+    process.argv.unshift('rhino');
+}
+
+function showUsage() {
+    console.log('Usage:');
+    console.log('   esparse [options] file.js');
+    console.log();
+    console.log('Available options:');
+    console.log();
+    console.log('  --comment      Gather all line and block comments in an array');
+    console.log('  --loc          Include line-column location info for each syntax node');
+    console.log('  --range        Include index-based range for each syntax node');
+    console.log('  --raw          Display the raw value of literals');
+    console.log('  --tokens       List all tokens in an array');
+    console.log('  --tolerant     Tolerate errors on a best-effort basis (experimental)');
+    console.log('  -v, --version  Shows program version');
+    console.log();
+    process.exit(1);
+}
+
+if (process.argv.length <= 2) {
+    showUsage();
+}
+
+options = {};
+
+process.argv.splice(2).forEach(function (entry) {
+
+    if (entry === '-h' || entry === '--help') {
+        showUsage();
+    } else if (entry === '-v' || entry === '--version') {
+        console.log('ECMAScript Parser (using Esprima version', esprima.version, ')');
+        console.log();
+        process.exit(0);
+    } else if (entry === '--comment') {
+        options.comment = true;
+    } else if (entry === '--loc') {
+        options.loc = true;
+    } else if (entry === '--range') {
+        options.range = true;
+    } else if (entry === '--raw') {
+        options.raw = true;
+    } else if (entry === '--tokens') {
+        options.tokens = true;
+    } else if (entry === '--tolerant') {
+        options.tolerant = true;
+    } else if (entry.slice(0, 2) === '--') {
+        console.log('Error: unknown option ' + entry + '.');
+        process.exit(1);
+    } else if (typeof fname === 'string') {
+        console.log('Error: more than one input file.');
+        process.exit(1);
+    } else {
+        fname = entry;
+    }
+});
+
+if (typeof fname !== 'string') {
+    console.log('Error: no input file.');
+    process.exit(1);
+}
+
+// Special handling for regular expression literal since we need to
+// convert it to a string literal, otherwise it will be decoded
+// as object "{}" and the regular expression would be lost.
+function adjustRegexLiteral(key, value) {
+    if (key === 'value' && value instanceof RegExp) {
+        value = value.toString();
+    }
+    return value;
+}
+
+try {
+    content = fs.readFileSync(fname, 'utf-8');
+    syntax = esprima.parse(content, options);
+    console.log(JSON.stringify(syntax, adjustRegexLiteral, 4));
+} catch (e) {
+    console.log('Error: ' + e.message);
+    process.exit(1);
+}
diff --git a/generator/node_modules/esprima/bin/esvalidate.js b/generator/node_modules/esprima/bin/esvalidate.js
new file mode 100755
index 0000000..f522dec
--- /dev/null
+++ b/generator/node_modules/esprima/bin/esvalidate.js
@@ -0,0 +1,199 @@
+#!/usr/bin/env node
+/*
+  Copyright (c) jQuery Foundation, Inc. and Contributors, All Rights Reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/*jslint sloppy:true plusplus:true node:true rhino:true */
+/*global phantom:true */
+
+var fs, system, esprima, options, fnames, count;
+
+if (typeof esprima === 'undefined') {
+    // PhantomJS can only require() relative files
+    if (typeof phantom === 'object') {
+        fs = require('fs');
+        system = require('system');
+        esprima = require('./esprima');
+    } else if (typeof require === 'function') {
+        fs = require('fs');
+        esprima = require('esprima');
+    } else if (typeof load === 'function') {
+        try {
+            load('esprima.js');
+        } catch (e) {
+            load('../esprima.js');
+        }
+    }
+}
+
+// Shims to Node.js objects when running under PhantomJS 1.7+.
+if (typeof phantom === 'object') {
+    fs.readFileSync = fs.read;
+    process = {
+        argv: [].slice.call(system.args),
+        exit: phantom.exit
+    };
+    process.argv.unshift('phantomjs');
+}
+
+// Shims to Node.js objects when running under Rhino.
+if (typeof console === 'undefined' && typeof process === 'undefined') {
+    console = { log: print };
+    fs = { readFileSync: readFile };
+    process = { argv: arguments, exit: quit };
+    process.argv.unshift('esvalidate.js');
+    process.argv.unshift('rhino');
+}
+
+function showUsage() {
+    console.log('Usage:');
+    console.log('   esvalidate [options] file.js');
+    console.log();
+    console.log('Available options:');
+    console.log();
+    console.log('  --format=type  Set the report format, plain (default) or junit');
+    console.log('  -v, --version  Print program version');
+    console.log();
+    process.exit(1);
+}
+
+if (process.argv.length <= 2) {
+    showUsage();
+}
+
+options = {
+    format: 'plain'
+};
+
+fnames = [];
+
+process.argv.splice(2).forEach(function (entry) {
+
+    if (entry === '-h' || entry === '--help') {
+        showUsage();
+    } else if (entry === '-v' || entry === '--version') {
+        console.log('ECMAScript Validator (using Esprima version', esprima.version, ')');
+        console.log();
+        process.exit(0);
+    } else if (entry.slice(0, 9) === '--format=') {
+        options.format = entry.slice(9);
+        if (options.format !== 'plain' && options.format !== 'junit') {
+            console.log('Error: unknown report format ' + options.format + '.');
+            process.exit(1);
+        }
+    } else if (entry.slice(0, 2) === '--') {
+        console.log('Error: unknown option ' + entry + '.');
+        process.exit(1);
+    } else {
+        fnames.push(entry);
+    }
+});
+
+if (fnames.length === 0) {
+    console.log('Error: no input file.');
+    process.exit(1);
+}
+
+if (options.format === 'junit') {
+    console.log('<?xml version="1.0" encoding="UTF-8"?>');
+    console.log('<testsuites>');
+}
+
+count = 0;
+fnames.forEach(function (fname) {
+    var content, timestamp, syntax, name;
+    try {
+        content = fs.readFileSync(fname, 'utf-8');
+
+        if (content[0] === '#' && content[1] === '!') {
+            content = '//' + content.substr(2, content.length);
+        }
+
+        timestamp = Date.now();
+        syntax = esprima.parse(content, { tolerant: true });
+
+        if (options.format === 'junit') {
+
+            name = fname;
+            if (name.lastIndexOf('/') >= 0) {
+                name = name.slice(name.lastIndexOf('/') + 1);
+            }
+
+            console.log('<testsuite name="' + fname + '" errors="0" ' +
+                ' failures="' + syntax.errors.length + '" ' +
+                ' tests="' + syntax.errors.length + '" ' +
+                ' time="' + Math.round((Date.now() - timestamp) / 1000) +
+                '">');
+
+            syntax.errors.forEach(function (error) {
+                var msg = error.message;
+                msg = msg.replace(/^Line\ [0-9]*\:\ /, '');
+                console.log('  <testcase name="Line ' + error.lineNumber + ': ' + msg + '" ' +
+                    ' time="0">');
+                console.log('    <error type="SyntaxError" message="' + error.message + '">' +
+                    error.message + '(' + name + ':' + error.lineNumber + ')' +
+                    '</error>');
+                console.log('  </testcase>');
+            });
+
+            console.log('</testsuite>');
+
+        } else if (options.format === 'plain') {
+
+            syntax.errors.forEach(function (error) {
+                var msg = error.message;
+                msg = msg.replace(/^Line\ [0-9]*\:\ /, '');
+                msg = fname + ':' + error.lineNumber + ': ' + msg;
+                console.log(msg);
+                ++count;
+            });
+
+        }
+    } catch (e) {
+        ++count;
+        if (options.format === 'junit') {
+            console.log('<testsuite name="' + fname + '" errors="1" failures="0" tests="1" ' +
+                ' time="' + Math.round((Date.now() - timestamp) / 1000) + '">');
+            console.log(' <testcase name="' + e.message + '" ' + ' time="0">');
+            console.log(' <error type="ParseError" message="' + e.message + '">' +
+                e.message + '(' + fname + ((e.lineNumber) ? ':' + e.lineNumber : '') +
+                ')</error>');
+            console.log(' </testcase>');
+            console.log('</testsuite>');
+        } else {
+            console.log('Error: ' + e.message);
+        }
+    }
+});
+
+if (options.format === 'junit') {
+    console.log('</testsuites>');
+}
+
+if (count > 0) {
+    process.exit(1);
+}
+
+if (count === 0 && typeof phantom === 'object') {
+    process.exit(0);
+}
diff --git a/generator/node_modules/esprima/esprima.js b/generator/node_modules/esprima/esprima.js
new file mode 100644
index 0000000..d48eeea
--- /dev/null
+++ b/generator/node_modules/esprima/esprima.js
@@ -0,0 +1,5661 @@
+/*
+  Copyright (c) jQuery Foundation, Inc. and Contributors, All Rights Reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+(function (root, factory) {
+    'use strict';
+
+    // Universal Module Definition (UMD) to support AMD, CommonJS/Node.js,
+    // Rhino, and plain browser loading.
+
+    /* istanbul ignore next */
+    if (typeof define === 'function' && define.amd) {
+        define(['exports'], factory);
+    } else if (typeof exports !== 'undefined') {
+        factory(exports);
+    } else {
+        factory((root.esprima = {}));
+    }
+}(this, function (exports) {
+    'use strict';
+
+    var Token,
+        TokenName,
+        FnExprTokens,
+        Syntax,
+        PlaceHolders,
+        Messages,
+        Regex,
+        source,
+        strict,
+        index,
+        lineNumber,
+        lineStart,
+        hasLineTerminator,
+        lastIndex,
+        lastLineNumber,
+        lastLineStart,
+        startIndex,
+        startLineNumber,
+        startLineStart,
+        scanning,
+        length,
+        lookahead,
+        state,
+        extra,
+        isBindingElement,
+        isAssignmentTarget,
+        firstCoverInitializedNameError;
+
+    Token = {
+        BooleanLiteral: 1,
+        EOF: 2,
+        Identifier: 3,
+        Keyword: 4,
+        NullLiteral: 5,
+        NumericLiteral: 6,
+        Punctuator: 7,
+        StringLiteral: 8,
+        RegularExpression: 9,
+        Template: 10
+    };
+
+    TokenName = {};
+    TokenName[Token.BooleanLiteral] = 'Boolean';
+    TokenName[Token.EOF] = '<end>';
+    TokenName[Token.Identifier] = 'Identifier';
+    TokenName[Token.Keyword] = 'Keyword';
+    TokenName[Token.NullLiteral] = 'Null';
+    TokenName[Token.NumericLiteral] = 'Numeric';
+    TokenName[Token.Punctuator] = 'Punctuator';
+    TokenName[Token.StringLiteral] = 'String';
+    TokenName[Token.RegularExpression] = 'RegularExpression';
+    TokenName[Token.Template] = 'Template';
+
+    // A function following one of those tokens is an expression.
+    FnExprTokens = ['(', '{', '[', 'in', 'typeof', 'instanceof', 'new',
+                    'return', 'case', 'delete', 'throw', 'void',
+                    // assignment operators
+                    '=', '+=', '-=', '*=', '/=', '%=', '<<=', '>>=', '>>>=',
+                    '&=', '|=', '^=', ',',
+                    // binary/unary operators
+                    '+', '-', '*', '/', '%', '++', '--', '<<', '>>', '>>>', '&',
+                    '|', '^', '!', '~', '&&', '||', '?', ':', '===', '==', '>=',
+                    '<=', '<', '>', '!=', '!=='];
+
+    Syntax = {
+        AssignmentExpression: 'AssignmentExpression',
+        AssignmentPattern: 'AssignmentPattern',
+        ArrayExpression: 'ArrayExpression',
+        ArrayPattern: 'ArrayPattern',
+        ArrowFunctionExpression: 'ArrowFunctionExpression',
+        BlockStatement: 'BlockStatement',
+        BinaryExpression: 'BinaryExpression',
+        BreakStatement: 'BreakStatement',
+        CallExpression: 'CallExpression',
+        CatchClause: 'CatchClause',
+        ClassBody: 'ClassBody',
+        ClassDeclaration: 'ClassDeclaration',
+        ClassExpression: 'ClassExpression',
+        ConditionalExpression: 'ConditionalExpression',
+        ContinueStatement: 'ContinueStatement',
+        DoWhileStatement: 'DoWhileStatement',
+        DebuggerStatement: 'DebuggerStatement',
+        EmptyStatement: 'EmptyStatement',
+        ExportAllDeclaration: 'ExportAllDeclaration',
+        ExportDefaultDeclaration: 'ExportDefaultDeclaration',
+        ExportNamedDeclaration: 'ExportNamedDeclaration',
+        ExportSpecifier: 'ExportSpecifier',
+        ExpressionStatement: 'ExpressionStatement',
+        ForStatement: 'ForStatement',
+        ForOfStatement: 'ForOfStatement',
+        ForInStatement: 'ForInStatement',
+        FunctionDeclaration: 'FunctionDeclaration',
+        FunctionExpression: 'FunctionExpression',
+        Identifier: 'Identifier',
+        IfStatement: 'IfStatement',
+        ImportDeclaration: 'ImportDeclaration',
+        ImportDefaultSpecifier: 'ImportDefaultSpecifier',
+        ImportNamespaceSpecifier: 'ImportNamespaceSpecifier',
+        ImportSpecifier: 'ImportSpecifier',
+        Literal: 'Literal',
+        LabeledStatement: 'LabeledStatement',
+        LogicalExpression: 'LogicalExpression',
+        MemberExpression: 'MemberExpression',
+        MetaProperty: 'MetaProperty',
+        MethodDefinition: 'MethodDefinition',
+        NewExpression: 'NewExpression',
+        ObjectExpression: 'ObjectExpression',
+        ObjectPattern: 'ObjectPattern',
+        Program: 'Program',
+        Property: 'Property',
+        RestElement: 'RestElement',
+        ReturnStatement: 'ReturnStatement',
+        SequenceExpression: 'SequenceExpression',
+        SpreadElement: 'SpreadElement',
+        Super: 'Super',
+        SwitchCase: 'SwitchCase',
+        SwitchStatement: 'SwitchStatement',
+        TaggedTemplateExpression: 'TaggedTemplateExpression',
+        TemplateElement: 'TemplateElement',
+        TemplateLiteral: 'TemplateLiteral',
+        ThisExpression: 'ThisExpression',
+        ThrowStatement: 'ThrowStatement',
+        TryStatement: 'TryStatement',
+        UnaryExpression: 'UnaryExpression',
+        UpdateExpression: 'UpdateExpression',
+        VariableDeclaration: 'VariableDeclaration',
+        VariableDeclarator: 'VariableDeclarator',
+        WhileStatement: 'WhileStatement',
+        WithStatement: 'WithStatement',
+        YieldExpression: 'YieldExpression'
+    };
+
+    PlaceHolders = {
+        ArrowParameterPlaceHolder: 'ArrowParameterPlaceHolder'
+    };
+
+    // Error messages should be identical to V8.
+    Messages = {
+        UnexpectedToken: 'Unexpected token %0',
+        UnexpectedNumber: 'Unexpected number',
+        UnexpectedString: 'Unexpected string',
+        UnexpectedIdentifier: 'Unexpected identifier',
+        UnexpectedReserved: 'Unexpected reserved word',
+        UnexpectedTemplate: 'Unexpected quasi %0',
+        UnexpectedEOS: 'Unexpected end of input',
+        NewlineAfterThrow: 'Illegal newline after throw',
+        InvalidRegExp: 'Invalid regular expression',
+        UnterminatedRegExp: 'Invalid regular expression: missing /',
+        InvalidLHSInAssignment: 'Invalid left-hand side in assignment',
+        InvalidLHSInForIn: 'Invalid left-hand side in for-in',
+        InvalidLHSInForLoop: 'Invalid left-hand side in for-loop',
+        MultipleDefaultsInSwitch: 'More than one default clause in switch statement',
+        NoCatchOrFinally: 'Missing catch or finally after try',
+        UnknownLabel: 'Undefined label \'%0\'',
+        Redeclaration: '%0 \'%1\' has already been declared',
+        IllegalContinue: 'Illegal continue statement',
+        IllegalBreak: 'Illegal break statement',
+        IllegalReturn: 'Illegal return statement',
+        StrictModeWith: 'Strict mode code may not include a with statement',
+        StrictCatchVariable: 'Catch variable may not be eval or arguments in strict mode',
+        StrictVarName: 'Variable name may not be eval or arguments in strict mode',
+        StrictParamName: 'Parameter name eval or arguments is not allowed in strict mode',
+        StrictParamDupe: 'Strict mode function may not have duplicate parameter names',
+        StrictFunctionName: 'Function name may not be eval or arguments in strict mode',
+        StrictOctalLiteral: 'Octal literals are not allowed in strict mode.',
+        StrictDelete: 'Delete of an unqualified identifier in strict mode.',
+        StrictLHSAssignment: 'Assignment to eval or arguments is not allowed in strict mode',
+        StrictLHSPostfix: 'Postfix increment/decrement may not have eval or arguments operand in strict mode',
+        StrictLHSPrefix: 'Prefix increment/decrement may not have eval or arguments operand in strict mode',
+        StrictReservedWord: 'Use of future reserved word in strict mode',
+        TemplateOctalLiteral: 'Octal literals are not allowed in template strings.',
+        ParameterAfterRestParameter: 'Rest parameter must be last formal parameter',
+        DefaultRestParameter: 'Unexpected token =',
+        ObjectPatternAsRestParameter: 'Unexpected token {',
+        DuplicateProtoProperty: 'Duplicate __proto__ fields are not allowed in object literals',
+        ConstructorSpecialMethod: 'Class constructor may not be an accessor',
+        DuplicateConstructor: 'A class may only have one constructor',
+        StaticPrototype: 'Classes may not have static property named prototype',
+        MissingFromClause: 'Unexpected token',
+        NoAsAfterImportNamespace: 'Unexpected token',
+        InvalidModuleSpecifier: 'Unexpected token',
+        IllegalImportDeclaration: 'Unexpected token',
+        IllegalExportDeclaration: 'Unexpected token',
+        DuplicateBinding: 'Duplicate binding %0'
+    };
+
+    // See also tools/generate-unicode-regex.js.
+    Regex = {
+        // ECMAScript 6/Unicode v7.0.0 NonAsciiIdentifierStart:
+        NonAsciiIdentifierStart: /[\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]|\uD800[\uDC00-\uDC0B\uDC0D-\uDC26\uDC28-\uDC3A\uDC3C\uDC3D\uDC3F-\uDC4D\uDC50-\uDC5D\uDC80-\uDCFA\uDD40-\uDD74\uDE80-\uDE9C\uDEA0-\uDED0\uDF00-\uDF1F\uDF30-\uDF4A\uDF50-\uDF75\uDF80-\uDF9D\uDFA0-\uDFC3\uDFC8-\uDFCF\uDFD1-\uDFD5]|\uD801[\uDC00-\uDC9D\uDD00-\uDD27\uDD30-\uDD63\uDE00-\uDF36\uDF40-\uDF55\uDF60-\uDF67]|\uD802[\uDC00-\uDC05\uDC08\uDC0A-\uDC35\uDC37\uDC38\uDC3C\uDC3F-\uDC55\uDC60-\uDC76\uDC80-\uDC9E\uDD00-\uDD15\uDD20-\uDD39\uDD80-\uDDB7\uDDBE\uDDBF\uDE00\uDE10-\uDE13\uDE15-\uDE17\uDE19-\uDE33\uDE60-\uDE7C\uDE80-\uDE9C\uDEC0-\uDEC7\uDEC9-\uDEE4\uDF00-\uDF35\uDF40-\uDF55\uDF60-\uDF72\uDF80-\uDF91]|\uD803[\uDC00-\uDC48]|\uD804[\uDC03-\uDC37\uDC83-\uDCAF\uDCD0-\uDCE8\uDD03-\uDD26\uDD50-\uDD72\uDD76\uDD83-\uDDB2\uDDC1-\uDDC4\uDDDA\uDE00-\uDE11\uDE13-\uDE2B\uDEB0-\uDEDE\uDF05-\uDF0C\uDF0F\uDF10\uDF13-\uDF28\uDF2A-\uDF30\uDF32\uDF33\uDF35-\uDF39\uDF3D\uDF5D-\uDF61]|\uD805[\uDC80-\uDCAF\uDCC4\uDCC5\uDCC7\uDD80-\uDDAE\uDE00-\uDE2F\uDE44\uDE80-\uDEAA]|\uD806[\uDCA0-\uDCDF\uDCFF\uDEC0-\uDEF8]|\uD808[\uDC00-\uDF98]|\uD809[\uDC00-\uDC6E]|[\uD80C\uD840-\uD868\uD86A-\uD86C][\uDC00-\uDFFF]|\uD80D[\uDC00-\uDC2E]|\uD81A[\uDC00-\uDE38\uDE40-\uDE5E\uDED0-\uDEED\uDF00-\uDF2F\uDF40-\uDF43\uDF63-\uDF77\uDF7D-\uDF8F]|\uD81B[\uDF00-\uDF44\uDF50\uDF93-\uDF9F]|\uD82C[\uDC00\uDC01]|\uD82F[\uDC00-\uDC6A\uDC70-\uDC7C\uDC80-\uDC88\uDC90-\uDC99]|\uD835[\uDC00-\uDC54\uDC56-\uDC9C\uDC9E\uDC9F\uDCA2\uDCA5\uDCA6\uDCA9-\uDCAC\uDCAE-\uDCB9\uDCBB\uDCBD-\uDCC3\uDCC5-\uDD05\uDD07-\uDD0A\uDD0D-\uDD14\uDD16-\uDD1C\uDD1E-\uDD39\uDD3B-\uDD3E\uDD40-\uDD44\uDD46\uDD4A-\uDD50\uDD52-\uDEA5\uDEA8-\uDEC0\uDEC2-\uDEDA\uDEDC-\uDEFA\uDEFC-\uDF14\uDF16-\uDF34\uDF36-\uDF4E\uDF50-\uDF6E\uDF70-\uDF88\uDF8A-\uDFA8\uDFAA-\uDFC2\uDFC4-\uDFCB]|\uD83A[\uDC00-\uDCC4]|\uD83B[\uDE00-\uDE03\uDE05-\uDE1F\uDE21\uDE22\uDE24\uDE27\uDE29-\uDE32\uDE34-\uDE37\uDE39\uDE3B\uDE42\uDE47\uDE49\uDE4B\uDE4D-\uDE4F\uDE51\uDE52\uDE54\uDE57\uDE59\uDE5B\uDE5D\uDE5F\uDE61\uDE62\uDE64\uDE67-\uDE6A\uDE6C-\uDE72\uDE74-\uDE77\uDE79-\uDE7C\uDE7E\uDE80-\uDE89\uDE8B-\uDE9B\uDEA1-\uDEA3\uDEA5-\uDEA9\uDEAB-\uDEBB]|\uD869[\uDC00-\uDED6\uDF00-\uDFFF]|\uD86D[\uDC00-\uDF34\uDF40-\uDFFF]|\uD86E[\uDC00-\uDC1D]|\uD87E[\uDC00-\uDE1D]/,
+
+        // ECMAScript 6/Unicode v7.0.0 NonAsciiIdentifierPart:
+        NonAsciiIdentifierPart: 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uFFC7\uFFCA-\uFFCF\uFFD2-\uFFD7\uFFDA-\uFFDC]|\uD800[\uDC00-\uDC0B\uDC0D-\uDC26\uDC28-\uDC3A\uDC3C\uDC3D\uDC3F-\uDC4D\uDC50-\uDC5D\uDC80-\uDCFA\uDD40-\uDD74\uDDFD\uDE80-\uDE9C\uDEA0-\uDED0\uDEE0\uDF00-\uDF1F\uDF30-\uDF4A\uDF50-\uDF7A\uDF80-\uDF9D\uDFA0-\uDFC3\uDFC8-\uDFCF\uDFD1-\uDFD5]|\uD801[\uDC00-\uDC9D\uDCA0-\uDCA9\uDD00-\uDD27\uDD30-\uDD63\uDE00-\uDF36\uDF40-\uDF55\uDF60-\uDF67]|\uD802[\uDC00-\uDC05\uDC08\uDC0A-\uDC35\uDC37\uDC38\uDC3C\uDC3F-\uDC55\uDC60-\uDC76\uDC80-\uDC9E\uDD00-\uDD15\uDD20-\uDD39\uDD80-\uDDB7\uDDBE\uDDBF\uDE00-\uDE03\uDE05\uDE06\uDE0C-\uDE13\uDE15-\uDE17\uDE19-\uDE33\uDE38-\uDE3A\uDE3F\uDE60-\uDE7C\uDE80-\uDE9C\uDEC0-\uDEC7\uDEC9-\uDEE6\uDF00-\uDF35\uDF40-\uDF55\uDF60-\uDF72\uDF80-\uDF91]|\uD803[\uDC00-\uDC48]|\uD804[\uDC00-\uDC46\uDC66-\uDC6F\uDC7F-\uDCBA\uDCD0-\uDCE8\uDCF0-\uDCF9\uDD00-\uDD34\uDD36-\uDD3F\uDD50-\uDD73\uDD76\uDD80-\uDDC4\uDDD0-\uDDDA\uDE00-\uDE11\uDE13-\uDE37\uDEB0-\uDEEA\uDEF0-\uDEF9\uDF01-\uDF03\uDF05-\uDF0C\uDF0F\uDF10\uDF13-\uDF28\uDF2A-\uDF30\uDF32\uDF33\uDF35-\uDF39\uDF3C-\uDF44\uDF47\uDF48\uDF4B-\uDF4D\uDF57\uDF5D-\uDF63\uDF66-\uDF6C\uDF70-\uDF74]|\uD805[\uDC80-\uDCC5\uDCC7\uDCD0-\uDCD9\uDD80-\uDDB5\uDDB8-\uDDC0\uDE00-\uDE40\uDE44\uDE50-\uDE59\uDE80-\uDEB7\uDEC0-\uDEC9]|\uD806[\uDCA0-\uDCE9\uDCFF\uDEC0-\uDEF8]|\uD808[\uDC00-\uDF98]|\uD809[\uDC00-\uDC6E]|[\uD80C\uD840-\uD868\uD86A-\uD86C][\uDC00-\uDFFF]|\uD80D[\uDC00-\uDC2E]|\uD81A[\uDC00-\uDE38\uDE40-\uDE5E\uDE60-\uDE69\uDED0-\uDEED\uDEF0-\uDEF4\uDF00-\uDF36\uDF40-\uDF43\uDF50-\uDF59\uDF63-\uDF77\uDF7D-\uDF8F]|\uD81B[\uDF00-\uDF44\uDF50-\uDF7E\uDF8F-\uDF9F]|\uD82C[\uDC00\uDC01]|\uD82F[\uDC00-\uDC6A\uDC70-\uDC7C\uDC80-\uDC88\uDC90-\uDC99\uDC9D\uDC9E]|\uD834[\uDD65-\uDD69\uDD6D-\uDD72\uDD7B-\uDD82\uDD85-\uDD8B\uDDAA-\uDDAD\uDE42-\uDE44]|\uD835[\uDC00-\uDC54\uDC56-\uDC9C\uDC9E\uDC9F\uDCA2\uDCA5\uDCA6\uDCA9-\uDCAC\uDCAE-\uDCB9\uDCBB\uDCBD-\uDCC3\uDCC5-\uDD05\uDD07-\uDD0A\uDD0D-\uDD14\uDD16-\uDD1C\uDD1E-\uDD39\uDD3B-\uDD3E\uDD40-\uDD44\uDD46\uDD4A-\uDD50\uDD52-\uDEA5\uDEA8-\uDEC0\uDEC2-\uDEDA\uDEDC-\uDEFA\uDEFC-\uDF14\uDF16-\uDF34\uDF36-\uDF4E\uDF50-\uDF6E\uDF70-\uDF88\uDF8A-\uDFA8\uDFAA-\uDFC2\uDFC4-\uDFCB\uDFCE-\uDFFF]|\uD83A[\uDC00-\uDCC4\uDCD0-\uDCD6]|\uD83B[\uDE00-\uDE03\uDE05-\uDE1F\uDE21\uDE22\uDE24\uDE27\uDE29-\uDE32\uDE34-\uDE37\uDE39\uDE3B\uDE42\uDE47\uDE49\uDE4B\uDE4D-\uDE4F\uDE51\uDE52\uDE54\uDE57\uDE59\uDE5B\uDE5D\uDE5F\uDE61\uDE62\uDE64\uDE67-\uDE6A\uDE6C-\uDE72\uDE74-\uDE77\uDE79-\uDE7C\uDE7E\uDE80-\uDE89\uDE8B-\uDE9B\uDEA1-\uDEA3\uDEA5-\uDEA9\uDEAB-\uDEBB]|\uD869[\uDC00-\uDED6\uDF00-\uDFFF]|\uD86D[\uDC00-\uDF34\uDF40-\uDFFF]|\uD86E[\uDC00-\uDC1D]|\uD87E[\uDC00-\uDE1D]|\uDB40[\uDD00-\uDDEF]/
+    };
+
+    // Ensure the condition is true, otherwise throw an error.
+    // This is only to have a better contract semantic, i.e. another safety net
+    // to catch a logic error. The condition shall be fulfilled in normal case.
+    // Do NOT use this to enforce a certain condition on any user input.
+
+    function assert(condition, message) {
+        /* istanbul ignore if */
+        if (!condition) {
+            throw new Error('ASSERT: ' + message);
+        }
+    }
+
+    function isDecimalDigit(ch) {
+        return (ch >= 0x30 && ch <= 0x39);   // 0..9
+    }
+
+    function isHexDigit(ch) {
+        return '0123456789abcdefABCDEF'.indexOf(ch) >= 0;
+    }
+
+    function isOctalDigit(ch) {
+        return '01234567'.indexOf(ch) >= 0;
+    }
+
+    function octalToDecimal(ch) {
+        // \0 is not octal escape sequence
+        var octal = (ch !== '0'), code = '01234567'.indexOf(ch);
+
+        if (index < length && isOctalDigit(source[index])) {
+            octal = true;
+            code = code * 8 + '01234567'.indexOf(source[index++]);
+
+            // 3 digits are only allowed when string starts
+            // with 0, 1, 2, 3
+            if ('0123'.indexOf(ch) >= 0 &&
+                    index < length &&
+                    isOctalDigit(source[index])) {
+                code = code * 8 + '01234567'.indexOf(source[index++]);
+            }
+        }
+
+        return {
+            code: code,
+            octal: octal
+        };
+    }
+
+    // ECMA-262 11.2 White Space
+
+    function isWhiteSpace(ch) {
+        return (ch === 0x20) || (ch === 0x09) || (ch === 0x0B) || (ch === 0x0C) || (ch === 0xA0) ||
+            (ch >= 0x1680 && [0x1680, 0x180E, 0x2000, 0x2001, 0x2002, 0x2003, 0x2004, 0x2005, 0x2006, 0x2007, 0x2008, 0x2009, 0x200A, 0x202F, 0x205F, 0x3000, 0xFEFF].indexOf(ch) >= 0);
+    }
+
+    // ECMA-262 11.3 Line Terminators
+
+    function isLineTerminator(ch) {
+        return (ch === 0x0A) || (ch === 0x0D) || (ch === 0x2028) || (ch === 0x2029);
+    }
+
+    // ECMA-262 11.6 Identifier Names and Identifiers
+
+    function fromCodePoint(cp) {
+        return (cp < 0x10000) ? String.fromCharCode(cp) :
+            String.fromCharCode(0xD800 + ((cp - 0x10000) >> 10)) +
+            String.fromCharCode(0xDC00 + ((cp - 0x10000) & 1023));
+    }
+
+    function isIdentifierStart(ch) {
+        return (ch === 0x24) || (ch === 0x5F) ||  // $ (dollar) and _ (underscore)
+            (ch >= 0x41 && ch <= 0x5A) ||         // A..Z
+            (ch >= 0x61 && ch <= 0x7A) ||         // a..z
+            (ch === 0x5C) ||                      // \ (backslash)
+            ((ch >= 0x80) && Regex.NonAsciiIdentifierStart.test(fromCodePoint(ch)));
+    }
+
+    function isIdentifierPart(ch) {
+        return (ch === 0x24) || (ch === 0x5F) ||  // $ (dollar) and _ (underscore)
+            (ch >= 0x41 && ch <= 0x5A) ||         // A..Z
+            (ch >= 0x61 && ch <= 0x7A) ||         // a..z
+            (ch >= 0x30 && ch <= 0x39) ||         // 0..9
+            (ch === 0x5C) ||                      // \ (backslash)
+            ((ch >= 0x80) && Regex.NonAsciiIdentifierPart.test(fromCodePoint(ch)));
+    }
+
+    // ECMA-262 11.6.2.2 Future Reserved Words
+
+    function isFutureReservedWord(id) {
+        switch (id) {
+        case 'enum':
+        case 'export':
+        case 'import':
+        case 'super':
+            return true;
+        default:
+            return false;
+        }
+    }
+
+    function isStrictModeReservedWord(id) {
+        switch (id) {
+        case 'implements':
+        case 'interface':
+        case 'package':
+        case 'private':
+        case 'protected':
+        case 'public':
+        case 'static':
+        case 'yield':
+        case 'let':
+            return true;
+        default:
+            return false;
+        }
+    }
+
+    function isRestrictedWord(id) {
+        return id === 'eval' || id === 'arguments';
+    }
+
+    // ECMA-262 11.6.2.1 Keywords
+
+    function isKeyword(id) {
+
+        // 'const' is specialized as Keyword in V8.
+        // 'yield' and 'let' are for compatibility with SpiderMonkey and ES.next.
+        // Some others are from future reserved words.
+
+        switch (id.length) {
+        case 2:
+            return (id === 'if') || (id === 'in') || (id === 'do');
+        case 3:
+            return (id === 'var') || (id === 'for') || (id === 'new') ||
+                (id === 'try') || (id === 'let');
+        case 4:
+            return (id === 'this') || (id === 'else') || (id === 'case') ||
+                (id === 'void') || (id === 'with') || (id === 'enum');
+        case 5:
+            return (id === 'while') || (id === 'break') || (id === 'catch') ||
+                (id === 'throw') || (id === 'const') || (id === 'yield') ||
+                (id === 'class') || (id === 'super');
+        case 6:
+            return (id === 'return') || (id === 'typeof') || (id === 'delete') ||
+                (id === 'switch') || (id === 'export') || (id === 'import');
+        case 7:
+            return (id === 'default') || (id === 'finally') || (id === 'extends');
+        case 8:
+            return (id === 'function') || (id === 'continue') || (id === 'debugger');
+        case 10:
+            return (id === 'instanceof');
+        default:
+            return false;
+        }
+    }
+
+    // ECMA-262 11.4 Comments
+
+    function addComment(type, value, start, end, loc) {
+        var comment;
+
+        assert(typeof start === 'number', 'Comment must have valid position');
+
+        state.lastCommentStart = start;
+
+        comment = {
+            type: type,
+            value: value
+        };
+        if (extra.range) {
+            comment.range = [start, end];
+        }
+        if (extra.loc) {
+            comment.loc = loc;
+        }
+        extra.comments.push(comment);
+        if (extra.attachComment) {
+            extra.leadingComments.push(comment);
+            extra.trailingComments.push(comment);
+        }
+    }
+
+    function skipSingleLineComment(offset) {
+        var start, loc, ch, comment;
+
+        start = index - offset;
+        loc = {
+            start: {
+                line: lineNumber,
+                column: index - lineStart - offset
+            }
+        };
+
+        while (index < length) {
+            ch = source.charCodeAt(index);
+            ++index;
+            if (isLineTerminator(ch)) {
+                hasLineTerminator = true;
+                if (extra.comments) {
+                    comment = source.slice(start + offset, index - 1);
+                    loc.end = {
+                        line: lineNumber,
+                        column: index - lineStart - 1
+                    };
+                    addComment('Line', comment, start, index - 1, loc);
+                }
+                if (ch === 13 && source.charCodeAt(index) === 10) {
+                    ++index;
+                }
+                ++lineNumber;
+                lineStart = index;
+                return;
+            }
+        }
+
+        if (extra.comments) {
+            comment = source.slice(start + offset, index);
+            loc.end = {
+                line: lineNumber,
+                column: index - lineStart
+            };
+            addComment('Line', comment, start, index, loc);
+        }
+    }
+
+    function skipMultiLineComment() {
+        var start, loc, ch, comment;
+
+        if (extra.comments) {
+            start = index - 2;
+            loc = {
+                start: {
+                    line: lineNumber,
+                    column: index - lineStart - 2
+                }
+            };
+        }
+
+        while (index < length) {
+            ch = source.charCodeAt(index);
+            if (isLineTerminator(ch)) {
+                if (ch === 0x0D && source.charCodeAt(index + 1) === 0x0A) {
+                    ++index;
+                }
+                hasLineTerminator = true;
+                ++lineNumber;
+                ++index;
+                lineStart = index;
+            } else if (ch === 0x2A) {
+                // Block comment ends with '*/'.
+                if (source.charCodeAt(index + 1) === 0x2F) {
+                    ++index;
+                    ++index;
+                    if (extra.comments) {
+                        comment = source.slice(start + 2, index - 2);
+                        loc.end = {
+                            line: lineNumber,
+                            column: index - lineStart
+                        };
+                        addComment('Block', comment, start, index, loc);
+                    }
+                    return;
+                }
+                ++index;
+            } else {
+                ++index;
+            }
+        }
+
+        // Ran off the end of the file - the whole thing is a comment
+        if (extra.comments) {
+            loc.end = {
+                line: lineNumber,
+                column: index - lineStart
+            };
+            comment = source.slice(start + 2, index);
+            addComment('Block', comment, start, index, loc);
+        }
+        tolerateUnexpectedToken();
+    }
+
+    function skipComment() {
+        var ch, start;
+        hasLineTerminator = false;
+
+        start = (index === 0);
+        while (index < length) {
+            ch = source.charCodeAt(index);
+
+            if (isWhiteSpace(ch)) {
+                ++index;
+            } else if (isLineTerminator(ch)) {
+                hasLineTerminator = true;
+                ++index;
+                if (ch === 0x0D && source.charCodeAt(index) === 0x0A) {
+                    ++index;
+                }
+                ++lineNumber;
+                lineStart = index;
+                start = true;
+            } else if (ch === 0x2F) { // U+002F is '/'
+                ch = source.charCodeAt(index + 1);
+                if (ch === 0x2F) {
+                    ++index;
+                    ++index;
+                    skipSingleLineComment(2);
+                    start = true;
+                } else if (ch === 0x2A) {  // U+002A is '*'
+                    ++index;
+                    ++index;
+                    skipMultiLineComment();
+                } else {
+                    break;
+                }
+            } else if (start && ch === 0x2D) { // U+002D is '-'
+                // U+003E is '>'
+                if ((source.charCodeAt(index + 1) === 0x2D) && (source.charCodeAt(index + 2) === 0x3E)) {
+                    // '-->' is a single-line comment
+                    index += 3;
+                    skipSingleLineComment(3);
+                } else {
+                    break;
+                }
+            } else if (ch === 0x3C) { // U+003C is '<'
+                if (source.slice(index + 1, index + 4) === '!--') {
+                    ++index; // `<`
+                    ++index; // `!`
+                    ++index; // `-`
+                    ++index; // `-`
+                    skipSingleLineComment(4);
+                } else {
+                    break;
+                }
+            } else {
+                break;
+            }
+        }
+    }
+
+    function scanHexEscape(prefix) {
+        var i, len, ch, code = 0;
+
+        len = (prefix === 'u') ? 4 : 2;
+        for (i = 0; i < len; ++i) {
+            if (index < length && isHexDigit(source[index])) {
+                ch = source[index++];
+                code = code * 16 + '0123456789abcdef'.indexOf(ch.toLowerCase());
+            } else {
+                return '';
+            }
+        }
+        return String.fromCharCode(code);
+    }
+
+    function scanUnicodeCodePointEscape() {
+        var ch, code;
+
+        ch = source[index];
+        code = 0;
+
+        // At least, one hex digit is required.
+        if (ch === '}') {
+            throwUnexpectedToken();
+        }
+
+        while (index < length) {
+            ch = source[index++];
+            if (!isHexDigit(ch)) {
+                break;
+            }
+            code = code * 16 + '0123456789abcdef'.indexOf(ch.toLowerCase());
+        }
+
+        if (code > 0x10FFFF || ch !== '}') {
+            throwUnexpectedToken();
+        }
+
+        return fromCodePoint(code);
+    }
+
+    function codePointAt(i) {
+        var cp, first, second;
+
+        cp = source.charCodeAt(i);
+        if (cp >= 0xD800 && cp <= 0xDBFF) {
+            second = source.charCodeAt(i + 1);
+            if (second >= 0xDC00 && second <= 0xDFFF) {
+                first = cp;
+                cp = (first - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
+            }
+        }
+
+        return cp;
+    }
+
+    function getComplexIdentifier() {
+        var cp, ch, id;
+
+        cp = codePointAt(index);
+        id = fromCodePoint(cp);
+        index += id.length;
+
+        // '\u' (U+005C, U+0075) denotes an escaped character.
+        if (cp === 0x5C) {
+            if (source.charCodeAt(index) !== 0x75) {
+                throwUnexpectedToken();
+            }
+            ++index;
+            if (source[index] === '{') {
+                ++index;
+                ch = scanUnicodeCodePointEscape();
+            } else {
+                ch = scanHexEscape('u');
+                cp = ch.charCodeAt(0);
+                if (!ch || ch === '\\' || !isIdentifierStart(cp)) {
+                    throwUnexpectedToken();
+                }
+            }
+            id = ch;
+        }
+
+        while (index < length) {
+            cp = codePointAt(index);
+            if (!isIdentifierPart(cp)) {
+                break;
+            }
+            ch = fromCodePoint(cp);
+            id += ch;
+            index += ch.length;
+
+            // '\u' (U+005C, U+0075) denotes an escaped character.
+            if (cp === 0x5C) {
+                id = id.substr(0, id.length - 1);
+                if (source.charCodeAt(index) !== 0x75) {
+                    throwUnexpectedToken();
+                }
+                ++index;
+                if (source[index] === '{') {
+                    ++index;
+                    ch = scanUnicodeCodePointEscape();
+                } else {
+                    ch = scanHexEscape('u');
+                    cp = ch.charCodeAt(0);
+                    if (!ch || ch === '\\' || !isIdentifierPart(cp)) {
+                        throwUnexpectedToken();
+                    }
+                }
+                id += ch;
+            }
+        }
+
+        return id;
+    }
+
+    function getIdentifier() {
+        var start, ch;
+
+        start = index++;
+        while (index < length) {
+            ch = source.charCodeAt(index);
+            if (ch === 0x5C) {
+                // Blackslash (U+005C) marks Unicode escape sequence.
+                index = start;
+                return getComplexIdentifier();
+            } else if (ch >= 0xD800 && ch < 0xDFFF) {
+                // Need to handle surrogate pairs.
+                index = start;
+                return getComplexIdentifier();
+            }
+            if (isIdentifierPart(ch)) {
+                ++index;
+            } else {
+                break;
+            }
+        }
+
+        return source.slice(start, index);
+    }
+
+    function scanIdentifier() {
+        var start, id, type;
+
+        start = index;
+
+        // Backslash (U+005C) starts an escaped character.
+        id = (source.charCodeAt(index) === 0x5C) ? getComplexIdentifier() : getIdentifier();
+
+        // There is no keyword or literal with only one character.
+        // Thus, it must be an identifier.
+        if (id.length === 1) {
+            type = Token.Identifier;
+        } else if (isKeyword(id)) {
+            type = Token.Keyword;
+        } else if (id === 'null') {
+            type = Token.NullLiteral;
+        } else if (id === 'true' || id === 'false') {
+            type = Token.BooleanLiteral;
+        } else {
+            type = Token.Identifier;
+        }
+
+        return {
+            type: type,
+            value: id,
+            lineNumber: lineNumber,
+            lineStart: lineStart,
+            start: start,
+            end: index
+        };
+    }
+
+
+    // ECMA-262 11.7 Punctuators
+
+    function scanPunctuator() {
+        var token, str;
+
+        token = {
+            type: Token.Punctuator,
+            value: '',
+            lineNumber: lineNumber,
+            lineStart: lineStart,
+            start: index,
+            end: index
+        };
+
+        // Check for most common single-character punctuators.
+        str = source[index];
+        switch (str) {
+
+        case '(':
+            if (extra.tokenize) {
+                extra.openParenToken = extra.tokens.length;
+            }
+            ++index;
+            break;
+
+        case '{':
+            if (extra.tokenize) {
+                extra.openCurlyToken = extra.tokens.length;
+            }
+            state.curlyStack.push('{');
+            ++index;
+            break;
+
+        case '.':
+            ++index;
+            if (source[index] === '.' && source[index + 1] === '.') {
+                // Spread operator: ...
+                index += 2;
+                str = '...';
+            }
+            break;
+
+        case '}':
+            ++index;
+            state.curlyStack.pop();
+            break;
+        case ')':
+        case ';':
+        case ',':
+        case '[':
+        case ']':
+        case ':':
+        case '?':
+        case '~':
+            ++index;
+            break;
+
+        default:
+            // 4-character punctuator.
+            str = source.substr(index, 4);
+            if (str === '>>>=') {
+                index += 4;
+            } else {
+
+                // 3-character punctuators.
+                str = str.substr(0, 3);
+                if (str === '===' || str === '!==' || str === '>>>' ||
+                    str === '<<=' || str === '>>=') {
+                    index += 3;
+                } else {
+
+                    // 2-character punctuators.
+                    str = str.substr(0, 2);
+                    if (str === '&&' || str === '||' || str === '==' || str === '!=' ||
+                        str === '+=' || str === '-=' || str === '*=' || str === '/=' ||
+                        str === '++' || str === '--' || str === '<<' || str === '>>' ||
+                        str === '&=' || str === '|=' || str === '^=' || str === '%=' ||
+                        str === '<=' || str === '>=' || str === '=>') {
+                        index += 2;
+                    } else {
+
+                        // 1-character punctuators.
+                        str = source[index];
+                        if ('<>=!+-*%&|^/'.indexOf(str) >= 0) {
+                            ++index;
+                        }
+                    }
+                }
+            }
+        }
+
+        if (index === token.start) {
+            throwUnexpectedToken();
+        }
+
+        token.end = index;
+        token.value = str;
+        return token;
+    }
+
+    // ECMA-262 11.8.3 Numeric Literals
+
+    function scanHexLiteral(start) {
+        var number = '';
+
+        while (index < length) {
+            if (!isHexDigit(source[index])) {
+                break;
+            }
+            number += source[index++];
+        }
+
+        if (number.length === 0) {
+            throwUnexpectedToken();
+        }
+
+        if (isIdentifierStart(source.charCodeAt(index))) {
+            throwUnexpectedToken();
+        }
+
+        return {
+            type: Token.NumericLiteral,
+            value: parseInt('0x' + number, 16),
+            lineNumber: lineNumber,
+            lineStart: lineStart,
+            start: start,
+            end: index
+        };
+    }
+
+    function scanBinaryLiteral(start) {
+        var ch, number;
+
+        number = '';
+
+        while (index < length) {
+            ch = source[index];
+            if (ch !== '0' && ch !== '1') {
+                break;
+            }
+            number += source[index++];
+        }
+
+        if (number.length === 0) {
+            // only 0b or 0B
+            throwUnexpectedToken();
+        }
+
+        if (index < length) {
+            ch = source.charCodeAt(index);
+            /* istanbul ignore else */
+            if (isIdentifierStart(ch) || isDecimalDigit(ch)) {
+                throwUnexpectedToken();
+            }
+        }
+
+        return {
+            type: Token.NumericLiteral,
+            value: parseInt(number, 2),
+            lineNumber: lineNumber,
+            lineStart: lineStart,
+            start: start,
+            end: index
+        };
+    }
+
+    function scanOctalLiteral(prefix, start) {
+        var number, octal;
+
+        if (isOctalDigit(prefix)) {
+            octal = true;
+            number = '0' + source[index++];
+        } else {
+            octal = false;
+            ++index;
+            number = '';
+        }
+
+        while (index < length) {
+            if (!isOctalDigit(source[index])) {
+                break;
+            }
+            number += source[index++];
+        }
+
+        if (!octal && number.length === 0) {
+            // only 0o or 0O
+            throwUnexpectedToken();
+        }
+
+        if (isIdentifierStart(source.charCodeAt(index)) || isDecimalDigit(source.charCodeAt(index))) {
+            throwUnexpectedToken();
+        }
+
+        return {
+            type: Token.NumericLiteral,
+            value: parseInt(number, 8),
+            octal: octal,
+            lineNumber: lineNumber,
+            lineStart: lineStart,
+            start: start,
+            end: index
+        };
+    }
+
+    function isImplicitOctalLiteral() {
+        var i, ch;
+
+        // Implicit octal, unless there is a non-octal digit.
+        // (Annex B.1.1 on Numeric Literals)
+        for (i = index + 1; i < length; ++i) {
+            ch = source[i];
+            if (ch === '8' || ch === '9') {
+                return false;
+            }
+            if (!isOctalDigit(ch)) {
+                return true;
+            }
+        }
+
+        return true;
+    }
+
+    function scanNumericLiteral() {
+        var number, start, ch;
+
+        ch = source[index];
+        assert(isDecimalDigit(ch.charCodeAt(0)) || (ch === '.'),
+            'Numeric literal must start with a decimal digit or a decimal point');
+
+        start = index;
+        number = '';
+        if (ch !== '.') {
+            number = source[index++];
+            ch = source[index];
+
+            // Hex number starts with '0x'.
+            // Octal number starts with '0'.
+            // Octal number in ES6 starts with '0o'.
+            // Binary number in ES6 starts with '0b'.
+            if (number === '0') {
+                if (ch === 'x' || ch === 'X') {
+                    ++index;
+                    return scanHexLiteral(start);
+                }
+                if (ch === 'b' || ch === 'B') {
+                    ++index;
+                    return scanBinaryLiteral(start);
+                }
+                if (ch === 'o' || ch === 'O') {
+                    return scanOctalLiteral(ch, start);
+                }
+
+                if (isOctalDigit(ch)) {
+                    if (isImplicitOctalLiteral()) {
+                        return scanOctalLiteral(ch, start);
+                    }
+                }
+            }
+
+            while (isDecimalDigit(source.charCodeAt(index))) {
+                number += source[index++];
+            }
+            ch = source[index];
+        }
+
+        if (ch === '.') {
+            number += source[index++];
+            while (isDecimalDigit(source.charCodeAt(index))) {
+                number += source[index++];
+            }
+            ch = source[index];
+        }
+
+        if (ch === 'e' || ch === 'E') {
+            number += source[index++];
+
+            ch = source[index];
+            if (ch === '+' || ch === '-') {
+                number += source[index++];
+            }
+            if (isDecimalDigit(source.charCodeAt(index))) {
+                while (isDecimalDigit(source.charCodeAt(index))) {
+                    number += source[index++];
+                }
+            } else {
+                throwUnexpectedToken();
+            }
+        }
+
+        if (isIdentifierStart(source.charCodeAt(index))) {
+            throwUnexpectedToken();
+        }
+
+        return {
+            type: Token.NumericLiteral,
+            value: parseFloat(number),
+            lineNumber: lineNumber,
+            lineStart: lineStart,
+            start: start,
+            end: index
+        };
+    }
+
+    // ECMA-262 11.8.4 String Literals
+
+    function scanStringLiteral() {
+        var str = '', quote, start, ch, unescaped, octToDec, octal = false;
+
+        quote = source[index];
+        assert((quote === '\'' || quote === '"'),
+            'String literal must starts with a quote');
+
+        start = index;
+        ++index;
+
+        while (index < length) {
+            ch = source[index++];
+
+            if (ch === quote) {
+                quote = '';
+                break;
+            } else if (ch === '\\') {
+                ch = source[index++];
+                if (!ch || !isLineTerminator(ch.charCodeAt(0))) {
+                    switch (ch) {
+                    case 'u':
+                    case 'x':
+                        if (source[index] === '{') {
+                            ++index;
+                            str += scanUnicodeCodePointEscape();
+                        } else {
+                            unescaped = scanHexEscape(ch);
+                            if (!unescaped) {
+                                throw throwUnexpectedToken();
+                            }
+                            str += unescaped;
+                        }
+                        break;
+                    case 'n':
+                        str += '\n';
+                        break;
+                    case 'r':
+                        str += '\r';
+                        break;
+                    case 't':
+                        str += '\t';
+                        break;
+                    case 'b':
+                        str += '\b';
+                        break;
+                    case 'f':
+                        str += '\f';
+                        break;
+                    case 'v':
+                        str += '\x0B';
+                        break;
+                    case '8':
+                    case '9':
+                        str += ch;
+                        tolerateUnexpectedToken();
+                        break;
+
+                    default:
+                        if (isOctalDigit(ch)) {
+                            octToDec = octalToDecimal(ch);
+
+                            octal = octToDec.octal || octal;
+                            str += String.fromCharCode(octToDec.code);
+                        } else {
+                            str += ch;
+                        }
+                        break;
+                    }
+                } else {
+                    ++lineNumber;
+                    if (ch === '\r' && source[index] === '\n') {
+                        ++index;
+                    }
+                    lineStart = index;
+                }
+            } else if (isLineTerminator(ch.charCodeAt(0))) {
+                break;
+            } else {
+                str += ch;
+            }
+        }
+
+        if (quote !== '') {
+            throwUnexpectedToken();
+        }
+
+        return {
+            type: Token.StringLiteral,
+            value: str,
+            octal: octal,
+            lineNumber: startLineNumber,
+            lineStart: startLineStart,
+            start: start,
+            end: index
+        };
+    }
+
+    // ECMA-262 11.8.6 Template Literal Lexical Components
+
+    function scanTemplate() {
+        var cooked = '', ch, start, rawOffset, terminated, head, tail, restore, unescaped;
+
+        terminated = false;
+        tail = false;
+        start = index;
+        head = (source[index] === '`');
+        rawOffset = 2;
+
+        ++index;
+
+        while (index < length) {
+            ch = source[index++];
+            if (ch === '`') {
+                rawOffset = 1;
+                tail = true;
+                terminated = true;
+                break;
+            } else if (ch === '$') {
+                if (source[index] === '{') {
+                    state.curlyStack.push('${');
+                    ++index;
+                    terminated = true;
+                    break;
+                }
+                cooked += ch;
+            } else if (ch === '\\') {
+                ch = source[index++];
+                if (!isLineTerminator(ch.charCodeAt(0))) {
+                    switch (ch) {
+                    case 'n':
+                        cooked += '\n';
+                        break;
+                    case 'r':
+                        cooked += '\r';
+                        break;
+                    case 't':
+                        cooked += '\t';
+                        break;
+                    case 'u':
+                    case 'x':
+                        if (source[index] === '{') {
+                            ++index;
+                            cooked += scanUnicodeCodePointEscape();
+                        } else {
+                            restore = index;
+                            unescaped = scanHexEscape(ch);
+                            if (unescaped) {
+                                cooked += unescaped;
+                            } else {
+                                index = restore;
+                                cooked += ch;
+                            }
+                        }
+                        break;
+                    case 'b':
+                        cooked += '\b';
+                        break;
+                    case 'f':
+                        cooked += '\f';
+                        break;
+                    case 'v':
+                        cooked += '\v';
+                        break;
+
+                    default:
+                        if (ch === '0') {
+                            if (isDecimalDigit(source.charCodeAt(index))) {
+                                // Illegal: \01 \02 and so on
+                                throwError(Messages.TemplateOctalLiteral);
+                            }
+                            cooked += '\0';
+                        } else if (isOctalDigit(ch)) {
+                            // Illegal: \1 \2
+                            throwError(Messages.TemplateOctalLiteral);
+                        } else {
+                            cooked += ch;
+                        }
+                        break;
+                    }
+                } else {
+                    ++lineNumber;
+                    if (ch === '\r' && source[index] === '\n') {
+                        ++index;
+                    }
+                    lineStart = index;
+                }
+            } else if (isLineTerminator(ch.charCodeAt(0))) {
+                ++lineNumber;
+                if (ch === '\r' && source[index] === '\n') {
+                    ++index;
+                }
+                lineStart = index;
+                cooked += '\n';
+            } else {
+                cooked += ch;
+            }
+        }
+
+        if (!terminated) {
+            throwUnexpectedToken();
+        }
+
+        if (!head) {
+            state.curlyStack.pop();
+        }
+
+        return {
+            type: Token.Template,
+            value: {
+                cooked: cooked,
+                raw: source.slice(start + 1, index - rawOffset)
+            },
+            head: head,
+            tail: tail,
+            lineNumber: lineNumber,
+            lineStart: lineStart,
+            start: start,
+            end: index
+        };
+    }
+
+    // ECMA-262 11.8.5 Regular Expression Literals
+
+    function testRegExp(pattern, flags) {
+        // The BMP character to use as a replacement for astral symbols when
+        // translating an ES6 "u"-flagged pattern to an ES5-compatible
+        // approximation.
+        // Note: replacing with '\uFFFF' enables false positives in unlikely
+        // scenarios. For example, `[\u{1044f}-\u{10440}]` is an invalid
+        // pattern that would not be detected by this substitution.
+        var astralSubstitute = '\uFFFF',
+            tmp = pattern;
+
+        if (flags.indexOf('u') >= 0) {
+            tmp = tmp
+                // Replace every Unicode escape sequence with the equivalent
+                // BMP character or a constant ASCII code point in the case of
+                // astral symbols. (See the above note on `astralSubstitute`
+                // for more information.)
+                .replace(/\\u\{([0-9a-fA-F]+)\}|\\u([a-fA-F0-9]{4})/g, function ($0, $1, $2) {
+                    var codePoint = parseInt($1 || $2, 16);
+                    if (codePoint > 0x10FFFF) {
+                        throwUnexpectedToken(null, Messages.InvalidRegExp);
+                    }
+                    if (codePoint <= 0xFFFF) {
+                        return String.fromCharCode(codePoint);
+                    }
+                    return astralSubstitute;
+                })
+                // Replace each paired surrogate with a single ASCII symbol to
+                // avoid throwing on regular expressions that are only valid in
+                // combination with the "u" flag.
+                .replace(
+                    /[\uD800-\uDBFF][\uDC00-\uDFFF]/g,
+                    astralSubstitute
+                );
+        }
+
+        // First, detect invalid regular expressions.
+        try {
+            RegExp(tmp);
+        } catch (e) {
+            throwUnexpectedToken(null, Messages.InvalidRegExp);
+        }
+
+        // Return a regular expression object for this pattern-flag pair, or
+        // `null` in case the current environment doesn't support the flags it
+        // uses.
+        try {
+            return new RegExp(pattern, flags);
+        } catch (exception) {
+            return null;
+        }
+    }
+
+    function scanRegExpBody() {
+        var ch, str, classMarker, terminated, body;
+
+        ch = source[index];
+        assert(ch === '/', 'Regular expression literal must start with a slash');
+        str = source[index++];
+
+        classMarker = false;
+        terminated = false;
+        while (index < length) {
+            ch = source[index++];
+            str += ch;
+            if (ch === '\\') {
+                ch = source[index++];
+                // ECMA-262 7.8.5
+                if (isLineTerminator(ch.charCodeAt(0))) {
+                    throwUnexpectedToken(null, Messages.UnterminatedRegExp);
+                }
+                str += ch;
+            } else if (isLineTerminator(ch.charCodeAt(0))) {
+                throwUnexpectedToken(null, Messages.UnterminatedRegExp);
+            } else if (classMarker) {
+                if (ch === ']') {
+                    classMarker = false;
+                }
+            } else {
+                if (ch === '/') {
+                    terminated = true;
+                    break;
+                } else if (ch === '[') {
+                    classMarker = true;
+                }
+            }
+        }
+
+        if (!terminated) {
+            throwUnexpectedToken(null, Messages.UnterminatedRegExp);
+        }
+
+        // Exclude leading and trailing slash.
+        body = str.substr(1, str.length - 2);
+        return {
+            value: body,
+            literal: str
+        };
+    }
+
+    function scanRegExpFlags() {
+        var ch, str, flags, restore;
+
+        str = '';
+        flags = '';
+        while (index < length) {
+            ch = source[index];
+            if (!isIdentifierPart(ch.charCodeAt(0))) {
+                break;
+            }
+
+            ++index;
+            if (ch === '\\' && index < length) {
+                ch = source[index];
+                if (ch === 'u') {
+                    ++index;
+                    restore = index;
+                    ch = scanHexEscape('u');
+                    if (ch) {
+                        flags += ch;
+                        for (str += '\\u'; restore < index; ++restore) {
+                            str += source[restore];
+                        }
+                    } else {
+                        index = restore;
+                        flags += 'u';
+                        str += '\\u';
+                    }
+                    tolerateUnexpectedToken();
+                } else {
+                    str += '\\';
+                    tolerateUnexpectedToken();
+                }
+            } else {
+                flags += ch;
+                str += ch;
+            }
+        }
+
+        return {
+            value: flags,
+            literal: str
+        };
+    }
+
+    function scanRegExp() {
+        var start, body, flags, value;
+        scanning = true;
+
+        lookahead = null;
+        skipComment();
+        start = index;
+
+        body = scanRegExpBody();
+        flags = scanRegExpFlags();
+        value = testRegExp(body.value, flags.value);
+        scanning = false;
+        if (extra.tokenize) {
+            return {
+                type: Token.RegularExpression,
+                value: value,
+                regex: {
+                    pattern: body.value,
+                    flags: flags.value
+                },
+                lineNumber: lineNumber,
+                lineStart: lineStart,
+                start: start,
+                end: index
+            };
+        }
+
+        return {
+            literal: body.literal + flags.literal,
+            value: value,
+            regex: {
+                pattern: body.value,
+                flags: flags.value
+            },
+            start: start,
+            end: index
+        };
+    }
+
+    function collectRegex() {
+        var pos, loc, regex, token;
+
+        skipComment();
+
+        pos = index;
+        loc = {
+            start: {
+                line: lineNumber,
+                column: index - lineStart
+            }
+        };
+
+        regex = scanRegExp();
+
+        loc.end = {
+            line: lineNumber,
+            column: index - lineStart
+        };
+
+        /* istanbul ignore next */
+        if (!extra.tokenize) {
+            // Pop the previous token, which is likely '/' or '/='
+            if (extra.tokens.length > 0) {
+                token = extra.tokens[extra.tokens.length - 1];
+                if (token.range[0] === pos && token.type === 'Punctuator') {
+                    if (token.value === '/' || token.value === '/=') {
+                        extra.tokens.pop();
+                    }
+                }
+            }
+
+            extra.tokens.push({
+                type: 'RegularExpression',
+                value: regex.literal,
+                regex: regex.regex,
+                range: [pos, index],
+                loc: loc
+            });
+        }
+
+        return regex;
+    }
+
+    function isIdentifierName(token) {
+        return token.type === Token.Identifier ||
+            token.type === Token.Keyword ||
+            token.type === Token.BooleanLiteral ||
+            token.type === Token.NullLiteral;
+    }
+
+    function advanceSlash() {
+        var prevToken,
+            checkToken;
+        // Using the following algorithm:
+        // https://github.com/mozilla/sweet.js/wiki/design
+        prevToken = extra.tokens[extra.tokens.length - 1];
+        if (!prevToken) {
+            // Nothing before that: it cannot be a division.
+            return collectRegex();
+        }
+        if (prevToken.type === 'Punctuator') {
+            if (prevToken.value === ']') {
+                return scanPunctuator();
+            }
+            if (prevToken.value === ')') {
+                checkToken = extra.tokens[extra.openParenToken - 1];
+                if (checkToken &&
+                        checkToken.type === 'Keyword' &&
+                        (checkToken.value === 'if' ||
+                         checkToken.value === 'while' ||
+                         checkToken.value === 'for' ||
+                         checkToken.value === 'with')) {
+                    return collectRegex();
+                }
+                return scanPunctuator();
+            }
+            if (prevToken.value === '}') {
+                // Dividing a function by anything makes little sense,
+                // but we have to check for that.
+                if (extra.tokens[extra.openCurlyToken - 3] &&
+                        extra.tokens[extra.openCurlyToken - 3].type === 'Keyword') {
+                    // Anonymous function.
+                    checkToken = extra.tokens[extra.openCurlyToken - 4];
+                    if (!checkToken) {
+                        return scanPunctuator();
+                    }
+                } else if (extra.tokens[extra.openCurlyToken - 4] &&
+                        extra.tokens[extra.openCurlyToken - 4].type === 'Keyword') {
+                    // Named function.
+                    checkToken = extra.tokens[extra.openCurlyToken - 5];
+                    if (!checkToken) {
+                        return collectRegex();
+                    }
+                } else {
+                    return scanPunctuator();
+                }
+                // checkToken determines whether the function is
+                // a declaration or an expression.
+                if (FnExprTokens.indexOf(checkToken.value) >= 0) {
+                    // It is an expression.
+                    return scanPunctuator();
+                }
+                // It is a declaration.
+                return collectRegex();
+            }
+            return collectRegex();
+        }
+        if (prevToken.type === 'Keyword' && prevToken.value !== 'this') {
+            return collectRegex();
+        }
+        return scanPunctuator();
+    }
+
+    function advance() {
+        var cp, token;
+
+        if (index >= length) {
+            return {
+                type: Token.EOF,
+                lineNumber: lineNumber,
+                lineStart: lineStart,
+                start: index,
+                end: index
+            };
+        }
+
+        cp = source.charCodeAt(index);
+
+        if (isIdentifierStart(cp)) {
+            token = scanIdentifier();
+            if (strict && isStrictModeReservedWord(token.value)) {
+                token.type = Token.Keyword;
+            }
+            return token;
+        }
+
+        // Very common: ( and ) and ;
+        if (cp === 0x28 || cp === 0x29 || cp === 0x3B) {
+            return scanPunctuator();
+        }
+
+        // String literal starts with single quote (U+0027) or double quote (U+0022).
+        if (cp === 0x27 || cp === 0x22) {
+            return scanStringLiteral();
+        }
+
+        // Dot (.) U+002E can also start a floating-point number, hence the need
+        // to check the next character.
+        if (cp === 0x2E) {
+            if (isDecimalDigit(source.charCodeAt(index + 1))) {
+                return scanNumericLiteral();
+            }
+            return scanPunctuator();
+        }
+
+        if (isDecimalDigit(cp)) {
+            return scanNumericLiteral();
+        }
+
+        // Slash (/) U+002F can also start a regex.
+        if (extra.tokenize && cp === 0x2F) {
+            return advanceSlash();
+        }
+
+        // Template literals start with ` (U+0060) for template head
+        // or } (U+007D) for template middle or template tail.
+        if (cp === 0x60 || (cp === 0x7D && state.curlyStack[state.curlyStack.length - 1] === '${')) {
+            return scanTemplate();
+        }
+
+        // Possible identifier start in a surrogate pair.
+        if (cp >= 0xD800 && cp < 0xDFFF) {
+            cp = codePointAt(index);
+            if (isIdentifierStart(cp)) {
+                return scanIdentifier();
+            }
+        }
+
+        return scanPunctuator();
+    }
+
+    function collectToken() {
+        var loc, token, value, entry;
+
+        loc = {
+            start: {
+                line: lineNumber,
+                column: index - lineStart
+            }
+        };
+
+        token = advance();
+        loc.end = {
+            line: lineNumber,
+            column: index - lineStart
+        };
+
+        if (token.type !== Token.EOF) {
+            value = source.slice(token.start, token.end);
+            entry = {
+                type: TokenName[token.type],
+                value: value,
+                range: [token.start, token.end],
+                loc: loc
+            };
+            if (token.regex) {
+                entry.regex = {
+                    pattern: token.regex.pattern,
+                    flags: token.regex.flags
+                };
+            }
+            extra.tokens.push(entry);
+        }
+
+        return token;
+    }
+
+    function lex() {
+        var token;
+        scanning = true;
+
+        lastIndex = index;
+        lastLineNumber = lineNumber;
+        lastLineStart = lineStart;
+
+        skipComment();
+
+        token = lookahead;
+
+        startIndex = index;
+        startLineNumber = lineNumber;
+        startLineStart = lineStart;
+
+        lookahead = (typeof extra.tokens !== 'undefined') ? collectToken() : advance();
+        scanning = false;
+        return token;
+    }
+
+    function peek() {
+        scanning = true;
+
+        skipComment();
+
+        lastIndex = index;
+        lastLineNumber = lineNumber;
+        lastLineStart = lineStart;
+
+        startIndex = index;
+        startLineNumber = lineNumber;
+        startLineStart = lineStart;
+
+        lookahead = (typeof extra.tokens !== 'undefined') ? collectToken() : advance();
+        scanning = false;
+    }
+
+    function Position() {
+        this.line = startLineNumber;
+        this.column = startIndex - startLineStart;
+    }
+
+    function SourceLocation() {
+        this.start = new Position();
+        this.end = null;
+    }
+
+    function WrappingSourceLocation(startToken) {
+        this.start = {
+            line: startToken.lineNumber,
+            column: startToken.start - startToken.lineStart
+        };
+        this.end = null;
+    }
+
+    function Node() {
+        if (extra.range) {
+            this.range = [startIndex, 0];
+        }
+        if (extra.loc) {
+            this.loc = new SourceLocation();
+        }
+    }
+
+    function WrappingNode(startToken) {
+        if (extra.range) {
+            this.range = [startToken.start, 0];
+        }
+        if (extra.loc) {
+            this.loc = new WrappingSourceLocation(startToken);
+        }
+    }
+
+    WrappingNode.prototype = Node.prototype = {
+
+        processComment: function () {
+            var lastChild,
+                leadingComments,
+                trailingComments,
+                bottomRight = extra.bottomRightStack,
+                i,
+                comment,
+                last = bottomRight[bottomRight.length - 1];
+
+            if (this.type === Syntax.Program) {
+                if (this.body.length > 0) {
+                    return;
+                }
+            }
+
+            if (extra.trailingComments.length > 0) {
+                trailingComments = [];
+                for (i = extra.trailingComments.length - 1; i >= 0; --i) {
+                    comment = extra.trailingComments[i];
+                    if (comment.range[0] >= this.range[1]) {
+                        trailingComments.unshift(comment);
+                        extra.trailingComments.splice(i, 1);
+                    }
+                }
+                extra.trailingComments = [];
+            } else {
+                if (last && last.trailingComments && last.trailingComments[0].range[0] >= this.range[1]) {
+                    trailingComments = last.trailingComments;
+                    delete last.trailingComments;
+                }
+            }
+
+            // Eating the stack.
+            while (last && last.range[0] >= this.range[0]) {
+                lastChild = bottomRight.pop();
+                last = bottomRight[bottomRight.length - 1];
+            }
+
+            if (lastChild) {
+                if (lastChild.leadingComments) {
+                    leadingComments = [];
+                    for (i = lastChild.leadingComments.length - 1; i >= 0; --i) {
+                        comment = lastChild.leadingComments[i];
+                        if (comment.range[1] <= this.range[0]) {
+                            leadingComments.unshift(comment);
+                            lastChild.leadingComments.splice(i, 1);
+                        }
+                    }
+
+                    if (!lastChild.leadingComments.length) {
+                        lastChild.leadingComments = undefined;
+                    }
+                }
+            } else if (extra.leadingComments.length > 0) {
+                leadingComments = [];
+                for (i = extra.leadingComments.length - 1; i >= 0; --i) {
+                    comment = extra.leadingComments[i];
+                    if (comment.range[1] <= this.range[0]) {
+                        leadingComments.unshift(comment);
+                        extra.leadingComments.splice(i, 1);
+                    }
+                }
+            }
+
+
+            if (leadingComments && leadingComments.length > 0) {
+                this.leadingComments = leadingComments;
+            }
+            if (trailingComments && trailingComments.length > 0) {
+                this.trailingComments = trailingComments;
+            }
+
+            bottomRight.push(this);
+        },
+
+        finish: function () {
+            if (extra.range) {
+                this.range[1] = lastIndex;
+            }
+            if (extra.loc) {
+                this.loc.end = {
+                    line: lastLineNumber,
+                    column: lastIndex - lastLineStart
+                };
+                if (extra.source) {
+                    this.loc.source = extra.source;
+                }
+            }
+
+            if (extra.attachComment) {
+                this.processComment();
+            }
+        },
+
+        finishArrayExpression: function (elements) {
+            this.type = Syntax.ArrayExpression;
+            this.elements = elements;
+            this.finish();
+            return this;
+        },
+
+        finishArrayPattern: function (elements) {
+            this.type = Syntax.ArrayPattern;
+            this.elements = elements;
+            this.finish();
+            return this;
+        },
+
+        finishArrowFunctionExpression: function (params, defaults, body, expression) {
+            this.type = Syntax.ArrowFunctionExpression;
+            this.id = null;
+            this.params = params;
+            this.defaults = defaults;
+            this.body = body;
+            this.generator = false;
+            this.expression = expression;
+            this.finish();
+            return this;
+        },
+
+        finishAssignmentExpression: function (operator, left, right) {
+            this.type = Syntax.AssignmentExpression;
+            this.operator = operator;
+            this.left = left;
+            this.right = right;
+            this.finish();
+            return this;
+        },
+
+        finishAssignmentPattern: function (left, right) {
+            this.type = Syntax.AssignmentPattern;
+            this.left = left;
+            this.right = right;
+            this.finish();
+            return this;
+        },
+
+        finishBinaryExpression: function (operator, left, right) {
+            this.type = (operator === '||' || operator === '&&') ? Syntax.LogicalExpression : Syntax.BinaryExpression;
+            this.operator = operator;
+            this.left = left;
+            this.right = right;
+            this.finish();
+            return this;
+        },
+
+        finishBlockStatement: function (body) {
+            this.type = Syntax.BlockStatement;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishBreakStatement: function (label) {
+            this.type = Syntax.BreakStatement;
+            this.label = label;
+            this.finish();
+            return this;
+        },
+
+        finishCallExpression: function (callee, args) {
+            this.type = Syntax.CallExpression;
+            this.callee = callee;
+            this.arguments = args;
+            this.finish();
+            return this;
+        },
+
+        finishCatchClause: function (param, body) {
+            this.type = Syntax.CatchClause;
+            this.param = param;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishClassBody: function (body) {
+            this.type = Syntax.ClassBody;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishClassDeclaration: function (id, superClass, body) {
+            this.type = Syntax.ClassDeclaration;
+            this.id = id;
+            this.superClass = superClass;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishClassExpression: function (id, superClass, body) {
+            this.type = Syntax.ClassExpression;
+            this.id = id;
+            this.superClass = superClass;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishConditionalExpression: function (test, consequent, alternate) {
+            this.type = Syntax.ConditionalExpression;
+            this.test = test;
+            this.consequent = consequent;
+            this.alternate = alternate;
+            this.finish();
+            return this;
+        },
+
+        finishContinueStatement: function (label) {
+            this.type = Syntax.ContinueStatement;
+            this.label = label;
+            this.finish();
+            return this;
+        },
+
+        finishDebuggerStatement: function () {
+            this.type = Syntax.DebuggerStatement;
+            this.finish();
+            return this;
+        },
+
+        finishDoWhileStatement: function (body, test) {
+            this.type = Syntax.DoWhileStatement;
+            this.body = body;
+            this.test = test;
+            this.finish();
+            return this;
+        },
+
+        finishEmptyStatement: function () {
+            this.type = Syntax.EmptyStatement;
+            this.finish();
+            return this;
+        },
+
+        finishExpressionStatement: function (expression) {
+            this.type = Syntax.ExpressionStatement;
+            this.expression = expression;
+            this.finish();
+            return this;
+        },
+
+        finishForStatement: function (init, test, update, body) {
+            this.type = Syntax.ForStatement;
+            this.init = init;
+            this.test = test;
+            this.update = update;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishForOfStatement: function (left, right, body) {
+            this.type = Syntax.ForOfStatement;
+            this.left = left;
+            this.right = right;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishForInStatement: function (left, right, body) {
+            this.type = Syntax.ForInStatement;
+            this.left = left;
+            this.right = right;
+            this.body = body;
+            this.each = false;
+            this.finish();
+            return this;
+        },
+
+        finishFunctionDeclaration: function (id, params, defaults, body, generator) {
+            this.type = Syntax.FunctionDeclaration;
+            this.id = id;
+            this.params = params;
+            this.defaults = defaults;
+            this.body = body;
+            this.generator = generator;
+            this.expression = false;
+            this.finish();
+            return this;
+        },
+
+        finishFunctionExpression: function (id, params, defaults, body, generator) {
+            this.type = Syntax.FunctionExpression;
+            this.id = id;
+            this.params = params;
+            this.defaults = defaults;
+            this.body = body;
+            this.generator = generator;
+            this.expression = false;
+            this.finish();
+            return this;
+        },
+
+        finishIdentifier: function (name) {
+            this.type = Syntax.Identifier;
+            this.name = name;
+            this.finish();
+            return this;
+        },
+
+        finishIfStatement: function (test, consequent, alternate) {
+            this.type = Syntax.IfStatement;
+            this.test = test;
+            this.consequent = consequent;
+            this.alternate = alternate;
+            this.finish();
+            return this;
+        },
+
+        finishLabeledStatement: function (label, body) {
+            this.type = Syntax.LabeledStatement;
+            this.label = label;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishLiteral: function (token) {
+            this.type = Syntax.Literal;
+            this.value = token.value;
+            this.raw = source.slice(token.start, token.end);
+            if (token.regex) {
+                this.regex = token.regex;
+            }
+            this.finish();
+            return this;
+        },
+
+        finishMemberExpression: function (accessor, object, property) {
+            this.type = Syntax.MemberExpression;
+            this.computed = accessor === '[';
+            this.object = object;
+            this.property = property;
+            this.finish();
+            return this;
+        },
+
+        finishMetaProperty: function (meta, property) {
+            this.type = Syntax.MetaProperty;
+            this.meta = meta;
+            this.property = property;
+            this.finish();
+            return this;
+        },
+
+        finishNewExpression: function (callee, args) {
+            this.type = Syntax.NewExpression;
+            this.callee = callee;
+            this.arguments = args;
+            this.finish();
+            return this;
+        },
+
+        finishObjectExpression: function (properties) {
+            this.type = Syntax.ObjectExpression;
+            this.properties = properties;
+            this.finish();
+            return this;
+        },
+
+        finishObjectPattern: function (properties) {
+            this.type = Syntax.ObjectPattern;
+            this.properties = properties;
+            this.finish();
+            return this;
+        },
+
+        finishPostfixExpression: function (operator, argument) {
+            this.type = Syntax.UpdateExpression;
+            this.operator = operator;
+            this.argument = argument;
+            this.prefix = false;
+            this.finish();
+            return this;
+        },
+
+        finishProgram: function (body, sourceType) {
+            this.type = Syntax.Program;
+            this.body = body;
+            this.sourceType = sourceType;
+            this.finish();
+            return this;
+        },
+
+        finishProperty: function (kind, key, computed, value, method, shorthand) {
+            this.type = Syntax.Property;
+            this.key = key;
+            this.computed = computed;
+            this.value = value;
+            this.kind = kind;
+            this.method = method;
+            this.shorthand = shorthand;
+            this.finish();
+            return this;
+        },
+
+        finishRestElement: function (argument) {
+            this.type = Syntax.RestElement;
+            this.argument = argument;
+            this.finish();
+            return this;
+        },
+
+        finishReturnStatement: function (argument) {
+            this.type = Syntax.ReturnStatement;
+            this.argument = argument;
+            this.finish();
+            return this;
+        },
+
+        finishSequenceExpression: function (expressions) {
+            this.type = Syntax.SequenceExpression;
+            this.expressions = expressions;
+            this.finish();
+            return this;
+        },
+
+        finishSpreadElement: function (argument) {
+            this.type = Syntax.SpreadElement;
+            this.argument = argument;
+            this.finish();
+            return this;
+        },
+
+        finishSwitchCase: function (test, consequent) {
+            this.type = Syntax.SwitchCase;
+            this.test = test;
+            this.consequent = consequent;
+            this.finish();
+            return this;
+        },
+
+        finishSuper: function () {
+            this.type = Syntax.Super;
+            this.finish();
+            return this;
+        },
+
+        finishSwitchStatement: function (discriminant, cases) {
+            this.type = Syntax.SwitchStatement;
+            this.discriminant = discriminant;
+            this.cases = cases;
+            this.finish();
+            return this;
+        },
+
+        finishTaggedTemplateExpression: function (tag, quasi) {
+            this.type = Syntax.TaggedTemplateExpression;
+            this.tag = tag;
+            this.quasi = quasi;
+            this.finish();
+            return this;
+        },
+
+        finishTemplateElement: function (value, tail) {
+            this.type = Syntax.TemplateElement;
+            this.value = value;
+            this.tail = tail;
+            this.finish();
+            return this;
+        },
+
+        finishTemplateLiteral: function (quasis, expressions) {
+            this.type = Syntax.TemplateLiteral;
+            this.quasis = quasis;
+            this.expressions = expressions;
+            this.finish();
+            return this;
+        },
+
+        finishThisExpression: function () {
+            this.type = Syntax.ThisExpression;
+            this.finish();
+            return this;
+        },
+
+        finishThrowStatement: function (argument) {
+            this.type = Syntax.ThrowStatement;
+            this.argument = argument;
+            this.finish();
+            return this;
+        },
+
+        finishTryStatement: function (block, handler, finalizer) {
+            this.type = Syntax.TryStatement;
+            this.block = block;
+            this.guardedHandlers = [];
+            this.handlers = handler ? [handler] : [];
+            this.handler = handler;
+            this.finalizer = finalizer;
+            this.finish();
+            return this;
+        },
+
+        finishUnaryExpression: function (operator, argument) {
+            this.type = (operator === '++' || operator === '--') ? Syntax.UpdateExpression : Syntax.UnaryExpression;
+            this.operator = operator;
+            this.argument = argument;
+            this.prefix = true;
+            this.finish();
+            return this;
+        },
+
+        finishVariableDeclaration: function (declarations) {
+            this.type = Syntax.VariableDeclaration;
+            this.declarations = declarations;
+            this.kind = 'var';
+            this.finish();
+            return this;
+        },
+
+        finishLexicalDeclaration: function (declarations, kind) {
+            this.type = Syntax.VariableDeclaration;
+            this.declarations = declarations;
+            this.kind = kind;
+            this.finish();
+            return this;
+        },
+
+        finishVariableDeclarator: function (id, init) {
+            this.type = Syntax.VariableDeclarator;
+            this.id = id;
+            this.init = init;
+            this.finish();
+            return this;
+        },
+
+        finishWhileStatement: function (test, body) {
+            this.type = Syntax.WhileStatement;
+            this.test = test;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishWithStatement: function (object, body) {
+            this.type = Syntax.WithStatement;
+            this.object = object;
+            this.body = body;
+            this.finish();
+            return this;
+        },
+
+        finishExportSpecifier: function (local, exported) {
+            this.type = Syntax.ExportSpecifier;
+            this.exported = exported || local;
+            this.local = local;
+            this.finish();
+            return this;
+        },
+
+        finishImportDefaultSpecifier: function (local) {
+            this.type = Syntax.ImportDefaultSpecifier;
+            this.local = local;
+            this.finish();
+            return this;
+        },
+
+        finishImportNamespaceSpecifier: function (local) {
+            this.type = Syntax.ImportNamespaceSpecifier;
+            this.local = local;
+            this.finish();
+            return this;
+        },
+
+        finishExportNamedDeclaration: function (declaration, specifiers, src) {
+            this.type = Syntax.ExportNamedDeclaration;
+            this.declaration = declaration;
+            this.specifiers = specifiers;
+            this.source = src;
+            this.finish();
+            return this;
+        },
+
+        finishExportDefaultDeclaration: function (declaration) {
+            this.type = Syntax.ExportDefaultDeclaration;
+            this.declaration = declaration;
+            this.finish();
+            return this;
+        },
+
+        finishExportAllDeclaration: function (src) {
+            this.type = Syntax.ExportAllDeclaration;
+            this.source = src;
+            this.finish();
+            return this;
+        },
+
+        finishImportSpecifier: function (local, imported) {
+            this.type = Syntax.ImportSpecifier;
+            this.local = local || imported;
+            this.imported = imported;
+            this.finish();
+            return this;
+        },
+
+        finishImportDeclaration: function (specifiers, src) {
+            this.type = Syntax.ImportDeclaration;
+            this.specifiers = specifiers;
+            this.source = src;
+            this.finish();
+            return this;
+        },
+
+        finishYieldExpression: function (argument, delegate) {
+            this.type = Syntax.YieldExpression;
+            this.argument = argument;
+            this.delegate = delegate;
+            this.finish();
+            return this;
+        }
+    };
+
+
+    function recordError(error) {
+        var e, existing;
+
+        for (e = 0; e < extra.errors.length; e++) {
+            existing = extra.errors[e];
+            // Prevent duplicated error.
+            /* istanbul ignore next */
+            if (existing.index === error.index && existing.message === error.message) {
+                return;
+            }
+        }
+
+        extra.errors.push(error);
+    }
+
+    function constructError(msg, column) {
+        var error = new Error(msg);
+        try {
+            throw error;
+        } catch (base) {
+            /* istanbul ignore else */
+            if (Object.create && Object.defineProperty) {
+                error = Object.create(base);
+                Object.defineProperty(error, 'column', { value: column });
+            }
+        } finally {
+            return error;
+        }
+    }
+
+    function createError(line, pos, description) {
+        var msg, column, error;
+
+        msg = 'Line ' + line + ': ' + description;
+        column = pos - (scanning ? lineStart : lastLineStart) + 1;
+        error = constructError(msg, column);
+        error.lineNumber = line;
+        error.description = description;
+        error.index = pos;
+        return error;
+    }
+
+    // Throw an exception
+
+    function throwError(messageFormat) {
+        var args, msg;
+
+        args = Array.prototype.slice.call(arguments, 1);
+        msg = messageFormat.replace(/%(\d)/g,
+            function (whole, idx) {
+                assert(idx < args.length, 'Message reference must be in range');
+                return args[idx];
+            }
+        );
+
+        throw createError(lastLineNumber, lastIndex, msg);
+    }
+
+    function tolerateError(messageFormat) {
+        var args, msg, error;
+
+        args = Array.prototype.slice.call(arguments, 1);
+        /* istanbul ignore next */
+        msg = messageFormat.replace(/%(\d)/g,
+            function (whole, idx) {
+                assert(idx < args.length, 'Message reference must be in range');
+                return args[idx];
+            }
+        );
+
+        error = createError(lineNumber, lastIndex, msg);
+        if (extra.errors) {
+            recordError(error);
+        } else {
+            throw error;
+        }
+    }
+
+    // Throw an exception because of the token.
+
+    function unexpectedTokenError(token, message) {
+        var value, msg = message || Messages.UnexpectedToken;
+
+        if (token) {
+            if (!message) {
+                msg = (token.type === Token.EOF) ? Messages.UnexpectedEOS :
+                    (token.type === Token.Identifier) ? Messages.UnexpectedIdentifier :
+                    (token.type === Token.NumericLiteral) ? Messages.UnexpectedNumber :
+                    (token.type === Token.StringLiteral) ? Messages.UnexpectedString :
+                    (token.type === Token.Template) ? Messages.UnexpectedTemplate :
+                    Messages.UnexpectedToken;
+
+                if (token.type === Token.Keyword) {
+                    if (isFutureReservedWord(token.value)) {
+                        msg = Messages.UnexpectedReserved;
+                    } else if (strict && isStrictModeReservedWord(token.value)) {
+                        msg = Messages.StrictReservedWord;
+                    }
+                }
+            }
+
+            value = (token.type === Token.Template) ? token.value.raw : token.value;
+        } else {
+            value = 'ILLEGAL';
+        }
+
+        msg = msg.replace('%0', value);
+
+        return (token && typeof token.lineNumber === 'number') ?
+            createError(token.lineNumber, token.start, msg) :
+            createError(scanning ? lineNumber : lastLineNumber, scanning ? index : lastIndex, msg);
+    }
+
+    function throwUnexpectedToken(token, message) {
+        throw unexpectedTokenError(token, message);
+    }
+
+    function tolerateUnexpectedToken(token, message) {
+        var error = unexpectedTokenError(token, message);
+        if (extra.errors) {
+            recordError(error);
+        } else {
+            throw error;
+        }
+    }
+
+    // Expect the next token to match the specified punctuator.
+    // If not, an exception will be thrown.
+
+    function expect(value) {
+        var token = lex();
+        if (token.type !== Token.Punctuator || token.value !== value) {
+            throwUnexpectedToken(token);
+        }
+    }
+
+    /**
+     * @name expectCommaSeparator
+     * @description Quietly expect a comma when in tolerant mode, otherwise delegates
+     * to <code>expect(value)</code>
+     * @since 2.0
+     */
+    function expectCommaSeparator() {
+        var token;
+
+        if (extra.errors) {
+            token = lookahead;
+            if (token.type === Token.Punctuator && token.value === ',') {
+                lex();
+            } else if (token.type === Token.Punctuator && token.value === ';') {
+                lex();
+                tolerateUnexpectedToken(token);
+            } else {
+                tolerateUnexpectedToken(token, Messages.UnexpectedToken);
+            }
+        } else {
+            expect(',');
+        }
+    }
+
+    // Expect the next token to match the specified keyword.
+    // If not, an exception will be thrown.
+
+    function expectKeyword(keyword) {
+        var token = lex();
+        if (token.type !== Token.Keyword || token.value !== keyword) {
+            throwUnexpectedToken(token);
+        }
+    }
+
+    // Return true if the next token matches the specified punctuator.
+
+    function match(value) {
+        return lookahead.type === Token.Punctuator && lookahead.value === value;
+    }
+
+    // Return true if the next token matches the specified keyword
+
+    function matchKeyword(keyword) {
+        return lookahead.type === Token.Keyword && lookahead.value === keyword;
+    }
+
+    // Return true if the next token matches the specified contextual keyword
+    // (where an identifier is sometimes a keyword depending on the context)
+
+    function matchContextualKeyword(keyword) {
+        return lookahead.type === Token.Identifier && lookahead.value === keyword;
+    }
+
+    // Return true if the next token is an assignment operator
+
+    function matchAssign() {
+        var op;
+
+        if (lookahead.type !== Token.Punctuator) {
+            return false;
+        }
+        op = lookahead.value;
+        return op === '=' ||
+            op === '*=' ||
+            op === '/=' ||
+            op === '%=' ||
+            op === '+=' ||
+            op === '-=' ||
+            op === '<<=' ||
+            op === '>>=' ||
+            op === '>>>=' ||
+            op === '&=' ||
+            op === '^=' ||
+            op === '|=';
+    }
+
+    function consumeSemicolon() {
+        // Catch the very common case first: immediately a semicolon (U+003B).
+        if (source.charCodeAt(startIndex) === 0x3B || match(';')) {
+            lex();
+            return;
+        }
+
+        if (hasLineTerminator) {
+            return;
+        }
+
+        // FIXME(ikarienator): this is seemingly an issue in the previous location info convention.
+        lastIndex = startIndex;
+        lastLineNumber = startLineNumber;
+        lastLineStart = startLineStart;
+
+        if (lookahead.type !== Token.EOF && !match('}')) {
+            throwUnexpectedToken(lookahead);
+        }
+    }
+
+    // Cover grammar support.
+    //
+    // When an assignment expression position starts with an left parenthesis, the determination of the type
+    // of the syntax is to be deferred arbitrarily long until the end of the parentheses pair (plus a lookahead)
+    // or the first comma. This situation also defers the determination of all the expressions nested in the pair.
+    //
+    // There are three productions that can be parsed in a parentheses pair that needs to be determined
+    // after the outermost pair is closed. They are:
+    //
+    //   1. AssignmentExpression
+    //   2. BindingElements
+    //   3. AssignmentTargets
+    //
+    // In order to avoid exponential backtracking, we use two flags to denote if the production can be
+    // binding element or assignment target.
+    //
+    // The three productions have the relationship:
+    //
+    //   BindingElements ⊆ AssignmentTargets ⊆ AssignmentExpression
+    //
+    // with a single exception that CoverInitializedName when used directly in an Expression, generates
+    // an early error. Therefore, we need the third state, firstCoverInitializedNameError, to track the
+    // first usage of CoverInitializedName and report it when we reached the end of the parentheses pair.
+    //
+    // isolateCoverGrammar function runs the given parser function with a new cover grammar context, and it does not
+    // effect the current flags. This means the production the parser parses is only used as an expression. Therefore
+    // the CoverInitializedName check is conducted.
+    //
+    // inheritCoverGrammar function runs the given parse function with a new cover grammar context, and it propagates
+    // the flags outside of the parser. This means the production the parser parses is used as a part of a potential
+    // pattern. The CoverInitializedName check is deferred.
+    function isolateCoverGrammar(parser) {
+        var oldIsBindingElement = isBindingElement,
+            oldIsAssignmentTarget = isAssignmentTarget,
+            oldFirstCoverInitializedNameError = firstCoverInitializedNameError,
+            result;
+        isBindingElement = true;
+        isAssignmentTarget = true;
+        firstCoverInitializedNameError = null;
+        result = parser();
+        if (firstCoverInitializedNameError !== null) {
+            throwUnexpectedToken(firstCoverInitializedNameError);
+        }
+        isBindingElement = oldIsBindingElement;
+        isAssignmentTarget = oldIsAssignmentTarget;
+        firstCoverInitializedNameError = oldFirstCoverInitializedNameError;
+        return result;
+    }
+
+    function inheritCoverGrammar(parser) {
+        var oldIsBindingElement = isBindingElement,
+            oldIsAssignmentTarget = isAssignmentTarget,
+            oldFirstCoverInitializedNameError = firstCoverInitializedNameError,
+            result;
+        isBindingElement = true;
+        isAssignmentTarget = true;
+        firstCoverInitializedNameError = null;
+        result = parser();
+        isBindingElement = isBindingElement && oldIsBindingElement;
+        isAssignmentTarget = isAssignmentTarget && oldIsAssignmentTarget;
+        firstCoverInitializedNameError = oldFirstCoverInitializedNameError || firstCoverInitializedNameError;
+        return result;
+    }
+
+    // ECMA-262 13.3.3 Destructuring Binding Patterns
+
+    function parseArrayPattern(params, kind) {
+        var node = new Node(), elements = [], rest, restNode;
+        expect('[');
+
+        while (!match(']')) {
+            if (match(',')) {
+                lex();
+                elements.push(null);
+            } else {
+                if (match('...')) {
+                    restNode = new Node();
+                    lex();
+                    params.push(lookahead);
+                    rest = parseVariableIdentifier(params, kind);
+                    elements.push(restNode.finishRestElement(rest));
+                    break;
+                } else {
+                    elements.push(parsePatternWithDefault(params, kind));
+                }
+                if (!match(']')) {
+                    expect(',');
+                }
+            }
+
+        }
+
+        expect(']');
+
+        return node.finishArrayPattern(elements);
+    }
+
+    function parsePropertyPattern(params, kind) {
+        var node = new Node(), key, keyToken, computed = match('['), init;
+        if (lookahead.type === Token.Identifier) {
+            keyToken = lookahead;
+            key = parseVariableIdentifier();
+            if (match('=')) {
+                params.push(keyToken);
+                lex();
+                init = parseAssignmentExpression();
+
+                return node.finishProperty(
+                    'init', key, false,
+                    new WrappingNode(keyToken).finishAssignmentPattern(key, init), false, false);
+            } else if (!match(':')) {
+                params.push(keyToken);
+                return node.finishProperty('init', key, false, key, false, true);
+            }
+        } else {
+            key = parseObjectPropertyKey(params, kind);
+        }
+        expect(':');
+        init = parsePatternWithDefault(params, kind);
+        return node.finishProperty('init', key, computed, init, false, false);
+    }
+
+    function parseObjectPattern(params, kind) {
+        var node = new Node(), properties = [];
+
+        expect('{');
+
+        while (!match('}')) {
+            properties.push(parsePropertyPattern(params, kind));
+            if (!match('}')) {
+                expect(',');
+            }
+        }
+
+        lex();
+
+        return node.finishObjectPattern(properties);
+    }
+
+    function parsePattern(params, kind) {
+        if (match('[')) {
+            return parseArrayPattern(params, kind);
+        } else if (match('{')) {
+            return parseObjectPattern(params, kind);
+        }
+        params.push(lookahead);
+        return parseVariableIdentifier(kind);
+    }
+
+    function parsePatternWithDefault(params, kind) {
+        var startToken = lookahead, pattern, previousAllowYield, right;
+        pattern = parsePattern(params, kind);
+        if (match('=')) {
+            lex();
+            previousAllowYield = state.allowYield;
+            state.allowYield = true;
+            right = isolateCoverGrammar(parseAssignmentExpression);
+            state.allowYield = previousAllowYield;
+            pattern = new WrappingNode(startToken).finishAssignmentPattern(pattern, right);
+        }
+        return pattern;
+    }
+
+    // ECMA-262 12.2.5 Array Initializer
+
+    function parseArrayInitializer() {
+        var elements = [], node = new Node(), restSpread;
+
+        expect('[');
+
+        while (!match(']')) {
+            if (match(',')) {
+                lex();
+                elements.push(null);
+            } else if (match('...')) {
+                restSpread = new Node();
+                lex();
+                restSpread.finishSpreadElement(inheritCoverGrammar(parseAssignmentExpression));
+
+                if (!match(']')) {
+                    isAssignmentTarget = isBindingElement = false;
+                    expect(',');
+                }
+                elements.push(restSpread);
+            } else {
+                elements.push(inheritCoverGrammar(parseAssignmentExpression));
+
+                if (!match(']')) {
+                    expect(',');
+                }
+            }
+        }
+
+        lex();
+
+        return node.finishArrayExpression(elements);
+    }
+
+    // ECMA-262 12.2.6 Object Initializer
+
+    function parsePropertyFunction(node, paramInfo, isGenerator) {
+        var previousStrict, body;
+
+        isAssignmentTarget = isBindingElement = false;
+
+        previousStrict = strict;
+        body = isolateCoverGrammar(parseFunctionSourceElements);
+
+        if (strict && paramInfo.firstRestricted) {
+            tolerateUnexpectedToken(paramInfo.firstRestricted, paramInfo.message);
+        }
+        if (strict && paramInfo.stricted) {
+            tolerateUnexpectedToken(paramInfo.stricted, paramInfo.message);
+        }
+
+        strict = previousStrict;
+        return node.finishFunctionExpression(null, paramInfo.params, paramInfo.defaults, body, isGenerator);
+    }
+
+    function parsePropertyMethodFunction() {
+        var params, method, node = new Node(),
+            previousAllowYield = state.allowYield;
+
+        state.allowYield = false;
+        params = parseParams();
+        state.allowYield = previousAllowYield;
+
+        state.allowYield = false;
+        method = parsePropertyFunction(node, params, false);
+        state.allowYield = previousAllowYield;
+
+        return method;
+    }
+
+    function parseObjectPropertyKey() {
+        var token, node = new Node(), expr;
+
+        token = lex();
+
+        // Note: This function is called only from parseObjectProperty(), where
+        // EOF and Punctuator tokens are already filtered out.
+
+        switch (token.type) {
+        case Token.StringLiteral:
+        case Token.NumericLiteral:
+            if (strict && token.octal) {
+                tolerateUnexpectedToken(token, Messages.StrictOctalLiteral);
+            }
+            return node.finishLiteral(token);
+        case Token.Identifier:
+        case Token.BooleanLiteral:
+        case Token.NullLiteral:
+        case Token.Keyword:
+            return node.finishIdentifier(token.value);
+        case Token.Punctuator:
+            if (token.value === '[') {
+                expr = isolateCoverGrammar(parseAssignmentExpression);
+                expect(']');
+                return expr;
+            }
+            break;
+        }
+        throwUnexpectedToken(token);
+    }
+
+    function lookaheadPropertyName() {
+        switch (lookahead.type) {
+        case Token.Identifier:
+        case Token.StringLiteral:
+        case Token.BooleanLiteral:
+        case Token.NullLiteral:
+        case Token.NumericLiteral:
+        case Token.Keyword:
+            return true;
+        case Token.Punctuator:
+            return lookahead.value === '[';
+        }
+        return false;
+    }
+
+    // This function is to try to parse a MethodDefinition as defined in 14.3. But in the case of object literals,
+    // it might be called at a position where there is in fact a short hand identifier pattern or a data property.
+    // This can only be determined after we consumed up to the left parentheses.
+    //
+    // In order to avoid back tracking, it returns `null` if the position is not a MethodDefinition and the caller
+    // is responsible to visit other options.
+    function tryParseMethodDefinition(token, key, computed, node) {
+        var value, options, methodNode, params,
+            previousAllowYield = state.allowYield;
+
+        if (token.type === Token.Identifier) {
+            // check for `get` and `set`;
+
+            if (token.value === 'get' && lookaheadPropertyName()) {
+                computed = match('[');
+                key = parseObjectPropertyKey();
+                methodNode = new Node();
+                expect('(');
+                expect(')');
+
+                state.allowYield = false;
+                value = parsePropertyFunction(methodNode, {
+                    params: [],
+                    defaults: [],
+                    stricted: null,
+                    firstRestricted: null,
+                    message: null
+                }, false);
+                state.allowYield = previousAllowYield;
+
+                return node.finishProperty('get', key, computed, value, false, false);
+            } else if (token.value === 'set' && lookaheadPropertyName()) {
+                computed = match('[');
+                key = parseObjectPropertyKey();
+                methodNode = new Node();
+                expect('(');
+
+                options = {
+                    params: [],
+                    defaultCount: 0,
+                    defaults: [],
+                    firstRestricted: null,
+                    paramSet: {}
+                };
+                if (match(')')) {
+                    tolerateUnexpectedToken(lookahead);
+                } else {
+                    state.allowYield = false;
+                    parseParam(options);
+                    state.allowYield = previousAllowYield;
+                    if (options.defaultCount === 0) {
+                        options.defaults = [];
+                    }
+                }
+                expect(')');
+
+                state.allowYield = false;
+                value = parsePropertyFunction(methodNode, options, false);
+                state.allowYield = previousAllowYield;
+
+                return node.finishProperty('set', key, computed, value, false, false);
+            }
+        } else if (token.type === Token.Punctuator && token.value === '*' && lookaheadPropertyName()) {
+            computed = match('[');
+            key = parseObjectPropertyKey();
+            methodNode = new Node();
+
+            state.allowYield = true;
+            params = parseParams();
+            state.allowYield = previousAllowYield;
+
+            state.allowYield = false;
+            value = parsePropertyFunction(methodNode, params, true);
+            state.allowYield = previousAllowYield;
+
+            return node.finishProperty('init', key, computed, value, true, false);
+        }
+
+        if (key && match('(')) {
+            value = parsePropertyMethodFunction();
+            return node.finishProperty('init', key, computed, value, true, false);
+        }
+
+        // Not a MethodDefinition.
+        return null;
+    }
+
+    function parseObjectProperty(hasProto) {
+        var token = lookahead, node = new Node(), computed, key, maybeMethod, proto, value;
+
+        computed = match('[');
+        if (match('*')) {
+            lex();
+        } else {
+            key = parseObjectPropertyKey();
+        }
+        maybeMethod = tryParseMethodDefinition(token, key, computed, node);
+        if (maybeMethod) {
+            return maybeMethod;
+        }
+
+        if (!key) {
+            throwUnexpectedToken(lookahead);
+        }
+
+        // Check for duplicated __proto__
+        if (!computed) {
+            proto = (key.type === Syntax.Identifier && key.name === '__proto__') ||
+                (key.type === Syntax.Literal && key.value === '__proto__');
+            if (hasProto.value && proto) {
+                tolerateError(Messages.DuplicateProtoProperty);
+            }
+            hasProto.value |= proto;
+        }
+
+        if (match(':')) {
+            lex();
+            value = inheritCoverGrammar(parseAssignmentExpression);
+            return node.finishProperty('init', key, computed, value, false, false);
+        }
+
+        if (token.type === Token.Identifier) {
+            if (match('=')) {
+                firstCoverInitializedNameError = lookahead;
+                lex();
+                value = isolateCoverGrammar(parseAssignmentExpression);
+                return node.finishProperty('init', key, computed,
+                    new WrappingNode(token).finishAssignmentPattern(key, value), false, true);
+            }
+            return node.finishProperty('init', key, computed, key, false, true);
+        }
+
+        throwUnexpectedToken(lookahead);
+    }
+
+    function parseObjectInitializer() {
+        var properties = [], hasProto = {value: false}, node = new Node();
+
+        expect('{');
+
+        while (!match('}')) {
+            properties.push(parseObjectProperty(hasProto));
+
+            if (!match('}')) {
+                expectCommaSeparator();
+            }
+        }
+
+        expect('}');
+
+        return node.finishObjectExpression(properties);
+    }
+
+    function reinterpretExpressionAsPattern(expr) {
+        var i;
+        switch (expr.type) {
+        case Syntax.Identifier:
+        case Syntax.MemberExpression:
+        case Syntax.RestElement:
+        case Syntax.AssignmentPattern:
+            break;
+        case Syntax.SpreadElement:
+            expr.type = Syntax.RestElement;
+            reinterpretExpressionAsPattern(expr.argument);
+            break;
+        case Syntax.ArrayExpression:
+            expr.type = Syntax.ArrayPattern;
+            for (i = 0; i < expr.elements.length; i++) {
+                if (expr.elements[i] !== null) {
+                    reinterpretExpressionAsPattern(expr.elements[i]);
+                }
+            }
+            break;
+        case Syntax.ObjectExpression:
+            expr.type = Syntax.ObjectPattern;
+            for (i = 0; i < expr.properties.length; i++) {
+                reinterpretExpressionAsPattern(expr.properties[i].value);
+            }
+            break;
+        case Syntax.AssignmentExpression:
+            expr.type = Syntax.AssignmentPattern;
+            reinterpretExpressionAsPattern(expr.left);
+            break;
+        default:
+            // Allow other node type for tolerant parsing.
+            break;
+        }
+    }
+
+    // ECMA-262 12.2.9 Template Literals
+
+    function parseTemplateElement(option) {
+        var node, token;
+
+        if (lookahead.type !== Token.Template || (option.head && !lookahead.head)) {
+            throwUnexpectedToken();
+        }
+
+        node = new Node();
+        token = lex();
+
+        return node.finishTemplateElement({ raw: token.value.raw, cooked: token.value.cooked }, token.tail);
+    }
+
+    function parseTemplateLiteral() {
+        var quasi, quasis, expressions, node = new Node();
+
+        quasi = parseTemplateElement({ head: true });
+        quasis = [quasi];
+        expressions = [];
+
+        while (!quasi.tail) {
+            expressions.push(parseExpression());
+            quasi = parseTemplateElement({ head: false });
+            quasis.push(quasi);
+        }
+
+        return node.finishTemplateLiteral(quasis, expressions);
+    }
+
+    // ECMA-262 12.2.10 The Grouping Operator
+
+    function parseGroupExpression() {
+        var expr, expressions, startToken, i, params = [];
+
+        expect('(');
+
+        if (match(')')) {
+            lex();
+            if (!match('=>')) {
+                expect('=>');
+            }
+            return {
+                type: PlaceHolders.ArrowParameterPlaceHolder,
+                params: [],
+                rawParams: []
+            };
+        }
+
+        startToken = lookahead;
+        if (match('...')) {
+            expr = parseRestElement(params);
+            expect(')');
+            if (!match('=>')) {
+                expect('=>');
+            }
+            return {
+                type: PlaceHolders.ArrowParameterPlaceHolder,
+                params: [expr]
+            };
+        }
+
+        isBindingElement = true;
+        expr = inheritCoverGrammar(parseAssignmentExpression);
+
+        if (match(',')) {
+            isAssignmentTarget = false;
+            expressions = [expr];
+
+            while (startIndex < length) {
+                if (!match(',')) {
+                    break;
+                }
+                lex();
+
+                if (match('...')) {
+                    if (!isBindingElement) {
+                        throwUnexpectedToken(lookahead);
+                    }
+                    expressions.push(parseRestElement(params));
+                    expect(')');
+                    if (!match('=>')) {
+                        expect('=>');
+                    }
+                    isBindingElement = false;
+                    for (i = 0; i < expressions.length; i++) {
+                        reinterpretExpressionAsPattern(expressions[i]);
+                    }
+                    return {
+                        type: PlaceHolders.ArrowParameterPlaceHolder,
+                        params: expressions
+                    };
+                }
+
+                expressions.push(inheritCoverGrammar(parseAssignmentExpression));
+            }
+
+            expr = new WrappingNode(startToken).finishSequenceExpression(expressions);
+        }
+
+
+        expect(')');
+
+        if (match('=>')) {
+            if (expr.type === Syntax.Identifier && expr.name === 'yield') {
+                return {
+                    type: PlaceHolders.ArrowParameterPlaceHolder,
+                    params: [expr]
+                };
+            }
+
+            if (!isBindingElement) {
+                throwUnexpectedToken(lookahead);
+            }
+
+            if (expr.type === Syntax.SequenceExpression) {
+                for (i = 0; i < expr.expressions.length; i++) {
+                    reinterpretExpressionAsPattern(expr.expressions[i]);
+                }
+            } else {
+                reinterpretExpressionAsPattern(expr);
+            }
+
+            expr = {
+                type: PlaceHolders.ArrowParameterPlaceHolder,
+                params: expr.type === Syntax.SequenceExpression ? expr.expressions : [expr]
+            };
+        }
+        isBindingElement = false;
+        return expr;
+    }
+
+
+    // ECMA-262 12.2 Primary Expressions
+
+    function parsePrimaryExpression() {
+        var type, token, expr, node;
+
+        if (match('(')) {
+            isBindingElement = false;
+            return inheritCoverGrammar(parseGroupExpression);
+        }
+
+        if (match('[')) {
+            return inheritCoverGrammar(parseArrayInitializer);
+        }
+
+        if (match('{')) {
+            return inheritCoverGrammar(parseObjectInitializer);
+        }
+
+        type = lookahead.type;
+        node = new Node();
+
+        if (type === Token.Identifier) {
+            if (state.sourceType === 'module' && lookahead.value === 'await') {
+                tolerateUnexpectedToken(lookahead);
+            }
+            expr = node.finishIdentifier(lex().value);
+        } else if (type === Token.StringLiteral || type === Token.NumericLiteral) {
+            isAssignmentTarget = isBindingElement = false;
+            if (strict && lookahead.octal) {
+                tolerateUnexpectedToken(lookahead, Messages.StrictOctalLiteral);
+            }
+            expr = node.finishLiteral(lex());
+        } else if (type === Token.Keyword) {
+            if (!strict && state.allowYield && matchKeyword('yield')) {
+                return parseNonComputedProperty();
+            }
+            isAssignmentTarget = isBindingElement = false;
+            if (matchKeyword('function')) {
+                return parseFunctionExpression();
+            }
+            if (matchKeyword('this')) {
+                lex();
+                return node.finishThisExpression();
+            }
+            if (matchKeyword('class')) {
+                return parseClassExpression();
+            }
+            throwUnexpectedToken(lex());
+        } else if (type === Token.BooleanLiteral) {
+            isAssignmentTarget = isBindingElement = false;
+            token = lex();
+            token.value = (token.value === 'true');
+            expr = node.finishLiteral(token);
+        } else if (type === Token.NullLiteral) {
+            isAssignmentTarget = isBindingElement = false;
+            token = lex();
+            token.value = null;
+            expr = node.finishLiteral(token);
+        } else if (match('/') || match('/=')) {
+            isAssignmentTarget = isBindingElement = false;
+            index = startIndex;
+
+            if (typeof extra.tokens !== 'undefined') {
+                token = collectRegex();
+            } else {
+                token = scanRegExp();
+            }
+            lex();
+            expr = node.finishLiteral(token);
+        } else if (type === Token.Template) {
+            expr = parseTemplateLiteral();
+        } else {
+            throwUnexpectedToken(lex());
+        }
+
+        return expr;
+    }
+
+    // ECMA-262 12.3 Left-Hand-Side Expressions
+
+    function parseArguments() {
+        var args = [], expr;
+
+        expect('(');
+
+        if (!match(')')) {
+            while (startIndex < length) {
+                if (match('...')) {
+                    expr = new Node();
+                    lex();
+                    expr.finishSpreadElement(isolateCoverGrammar(parseAssignmentExpression));
+                } else {
+                    expr = isolateCoverGrammar(parseAssignmentExpression);
+                }
+                args.push(expr);
+                if (match(')')) {
+                    break;
+                }
+                expectCommaSeparator();
+            }
+        }
+
+        expect(')');
+
+        return args;
+    }
+
+    function parseNonComputedProperty() {
+        var token, node = new Node();
+
+        token = lex();
+
+        if (!isIdentifierName(token)) {
+            throwUnexpectedToken(token);
+        }
+
+        return node.finishIdentifier(token.value);
+    }
+
+    function parseNonComputedMember() {
+        expect('.');
+
+        return parseNonComputedProperty();
+    }
+
+    function parseComputedMember() {
+        var expr;
+
+        expect('[');
+
+        expr = isolateCoverGrammar(parseExpression);
+
+        expect(']');
+
+        return expr;
+    }
+
+    // ECMA-262 12.3.3 The new Operator
+
+    function parseNewExpression() {
+        var callee, args, node = new Node();
+
+        expectKeyword('new');
+
+        if (match('.')) {
+            lex();
+            if (lookahead.type === Token.Identifier && lookahead.value === 'target') {
+                if (state.inFunctionBody) {
+                    lex();
+                    return node.finishMetaProperty('new', 'target');
+                }
+            }
+            throwUnexpectedToken(lookahead);
+        }
+
+        callee = isolateCoverGrammar(parseLeftHandSideExpression);
+        args = match('(') ? parseArguments() : [];
+
+        isAssignmentTarget = isBindingElement = false;
+
+        return node.finishNewExpression(callee, args);
+    }
+
+    // ECMA-262 12.3.4 Function Calls
+
+    function parseLeftHandSideExpressionAllowCall() {
+        var quasi, expr, args, property, startToken, previousAllowIn = state.allowIn;
+
+        startToken = lookahead;
+        state.allowIn = true;
+
+        if (matchKeyword('super') && state.inFunctionBody) {
+            expr = new Node();
+            lex();
+            expr = expr.finishSuper();
+            if (!match('(') && !match('.') && !match('[')) {
+                throwUnexpectedToken(lookahead);
+            }
+        } else {
+            expr = inheritCoverGrammar(matchKeyword('new') ? parseNewExpression : parsePrimaryExpression);
+        }
+
+        for (;;) {
+            if (match('.')) {
+                isBindingElement = false;
+                isAssignmentTarget = true;
+                property = parseNonComputedMember();
+                expr = new WrappingNode(startToken).finishMemberExpression('.', expr, property);
+            } else if (match('(')) {
+                isBindingElement = false;
+                isAssignmentTarget = false;
+                args = parseArguments();
+                expr = new WrappingNode(startToken).finishCallExpression(expr, args);
+            } else if (match('[')) {
+                isBindingElement = false;
+                isAssignmentTarget = true;
+                property = parseComputedMember();
+                expr = new WrappingNode(startToken).finishMemberExpression('[', expr, property);
+            } else if (lookahead.type === Token.Template && lookahead.head) {
+                quasi = parseTemplateLiteral();
+                expr = new WrappingNode(startToken).finishTaggedTemplateExpression(expr, quasi);
+            } else {
+                break;
+            }
+        }
+        state.allowIn = previousAllowIn;
+
+        return expr;
+    }
+
+    // ECMA-262 12.3 Left-Hand-Side Expressions
+
+    function parseLeftHandSideExpression() {
+        var quasi, expr, property, startToken;
+        assert(state.allowIn, 'callee of new expression always allow in keyword.');
+
+        startToken = lookahead;
+
+        if (matchKeyword('super') && state.inFunctionBody) {
+            expr = new Node();
+            lex();
+            expr = expr.finishSuper();
+            if (!match('[') && !match('.')) {
+                throwUnexpectedToken(lookahead);
+            }
+        } else {
+            expr = inheritCoverGrammar(matchKeyword('new') ? parseNewExpression : parsePrimaryExpression);
+        }
+
+        for (;;) {
+            if (match('[')) {
+                isBindingElement = false;
+                isAssignmentTarget = true;
+                property = parseComputedMember();
+                expr = new WrappingNode(startToken).finishMemberExpression('[', expr, property);
+            } else if (match('.')) {
+                isBindingElement = false;
+                isAssignmentTarget = true;
+                property = parseNonComputedMember();
+                expr = new WrappingNode(startToken).finishMemberExpression('.', expr, property);
+            } else if (lookahead.type === Token.Template && lookahead.head) {
+                quasi = parseTemplateLiteral();
+                expr = new WrappingNode(startToken).finishTaggedTemplateExpression(expr, quasi);
+            } else {
+                break;
+            }
+        }
+        return expr;
+    }
+
+    // ECMA-262 12.4 Postfix Expressions
+
+    function parsePostfixExpression() {
+        var expr, token, startToken = lookahead;
+
+        expr = inheritCoverGrammar(parseLeftHandSideExpressionAllowCall);
+
+        if (!hasLineTerminator && lookahead.type === Token.Punctuator) {
+            if (match('++') || match('--')) {
+                // ECMA-262 11.3.1, 11.3.2
+                if (strict && expr.type === Syntax.Identifier && isRestrictedWord(expr.name)) {
+                    tolerateError(Messages.StrictLHSPostfix);
+                }
+
+                if (!isAssignmentTarget) {
+                    tolerateError(Messages.InvalidLHSInAssignment);
+                }
+
+                isAssignmentTarget = isBindingElement = false;
+
+                token = lex();
+                expr = new WrappingNode(startToken).finishPostfixExpression(token.value, expr);
+            }
+        }
+
+        return expr;
+    }
+
+    // ECMA-262 12.5 Unary Operators
+
+    function parseUnaryExpression() {
+        var token, expr, startToken;
+
+        if (lookahead.type !== Token.Punctuator && lookahead.type !== Token.Keyword) {
+            expr = parsePostfixExpression();
+        } else if (match('++') || match('--')) {
+            startToken = lookahead;
+            token = lex();
+            expr = inheritCoverGrammar(parseUnaryExpression);
+            // ECMA-262 11.4.4, 11.4.5
+            if (strict && expr.type === Syntax.Identifier && isRestrictedWord(expr.name)) {
+                tolerateError(Messages.StrictLHSPrefix);
+            }
+
+            if (!isAssignmentTarget) {
+                tolerateError(Messages.InvalidLHSInAssignment);
+            }
+            expr = new WrappingNode(startToken).finishUnaryExpression(token.value, expr);
+            isAssignmentTarget = isBindingElement = false;
+        } else if (match('+') || match('-') || match('~') || match('!')) {
+            startToken = lookahead;
+            token = lex();
+            expr = inheritCoverGrammar(parseUnaryExpression);
+            expr = new WrappingNode(startToken).finishUnaryExpression(token.value, expr);
+            isAssignmentTarget = isBindingElement = false;
+        } else if (matchKeyword('delete') || matchKeyword('void') || matchKeyword('typeof')) {
+            startToken = lookahead;
+            token = lex();
+            expr = inheritCoverGrammar(parseUnaryExpression);
+            expr = new WrappingNode(startToken).finishUnaryExpression(token.value, expr);
+            if (strict && expr.operator === 'delete' && expr.argument.type === Syntax.Identifier) {
+                tolerateError(Messages.StrictDelete);
+            }
+            isAssignmentTarget = isBindingElement = false;
+        } else {
+            expr = parsePostfixExpression();
+        }
+
+        return expr;
+    }
+
+    function binaryPrecedence(token, allowIn) {
+        var prec = 0;
+
+        if (token.type !== Token.Punctuator && token.type !== Token.Keyword) {
+            return 0;
+        }
+
+        switch (token.value) {
+        case '||':
+            prec = 1;
+            break;
+
+        case '&&':
+            prec = 2;
+            break;
+
+        case '|':
+            prec = 3;
+            break;
+
+        case '^':
+            prec = 4;
+            break;
+
+        case '&':
+            prec = 5;
+            break;
+
+        case '==':
+        case '!=':
+        case '===':
+        case '!==':
+            prec = 6;
+            break;
+
+        case '<':
+        case '>':
+        case '<=':
+        case '>=':
+        case 'instanceof':
+            prec = 7;
+            break;
+
+        case 'in':
+            prec = allowIn ? 7 : 0;
+            break;
+
+        case '<<':
+        case '>>':
+        case '>>>':
+            prec = 8;
+            break;
+
+        case '+':
+        case '-':
+            prec = 9;
+            break;
+
+        case '*':
+        case '/':
+        case '%':
+            prec = 11;
+            break;
+
+        default:
+            break;
+        }
+
+        return prec;
+    }
+
+    // ECMA-262 12.6 Multiplicative Operators
+    // ECMA-262 12.7 Additive Operators
+    // ECMA-262 12.8 Bitwise Shift Operators
+    // ECMA-262 12.9 Relational Operators
+    // ECMA-262 12.10 Equality Operators
+    // ECMA-262 12.11 Binary Bitwise Operators
+    // ECMA-262 12.12 Binary Logical Operators
+
+    function parseBinaryExpression() {
+        var marker, markers, expr, token, prec, stack, right, operator, left, i;
+
+        marker = lookahead;
+        left = inheritCoverGrammar(parseUnaryExpression);
+
+        token = lookahead;
+        prec = binaryPrecedence(token, state.allowIn);
+        if (prec === 0) {
+            return left;
+        }
+        isAssignmentTarget = isBindingElement = false;
+        token.prec = prec;
+        lex();
+
+        markers = [marker, lookahead];
+        right = isolateCoverGrammar(parseUnaryExpression);
+
+        stack = [left, token, right];
+
+        while ((prec = binaryPrecedence(lookahead, state.allowIn)) > 0) {
+
+            // Reduce: make a binary expression from the three topmost entries.
+            while ((stack.length > 2) && (prec <= stack[stack.length - 2].prec)) {
+                right = stack.pop();
+                operator = stack.pop().value;
+                left = stack.pop();
+                markers.pop();
+                expr = new WrappingNode(markers[markers.length - 1]).finishBinaryExpression(operator, left, right);
+                stack.push(expr);
+            }
+
+            // Shift.
+            token = lex();
+            token.prec = prec;
+            stack.push(token);
+            markers.push(lookahead);
+            expr = isolateCoverGrammar(parseUnaryExpression);
+            stack.push(expr);
+        }
+
+        // Final reduce to clean-up the stack.
+        i = stack.length - 1;
+        expr = stack[i];
+        markers.pop();
+        while (i > 1) {
+            expr = new WrappingNode(markers.pop()).finishBinaryExpression(stack[i - 1].value, stack[i - 2], expr);
+            i -= 2;
+        }
+
+        return expr;
+    }
+
+
+    // ECMA-262 12.13 Conditional Operator
+
+    function parseConditionalExpression() {
+        var expr, previousAllowIn, consequent, alternate, startToken;
+
+        startToken = lookahead;
+
+        expr = inheritCoverGrammar(parseBinaryExpression);
+        if (match('?')) {
+            lex();
+            previousAllowIn = state.allowIn;
+            state.allowIn = true;
+            consequent = isolateCoverGrammar(parseAssignmentExpression);
+            state.allowIn = previousAllowIn;
+            expect(':');
+            alternate = isolateCoverGrammar(parseAssignmentExpression);
+
+            expr = new WrappingNode(startToken).finishConditionalExpression(expr, consequent, alternate);
+            isAssignmentTarget = isBindingElement = false;
+        }
+
+        return expr;
+    }
+
+    // ECMA-262 14.2 Arrow Function Definitions
+
+    function parseConciseBody() {
+        if (match('{')) {
+            return parseFunctionSourceElements();
+        }
+        return isolateCoverGrammar(parseAssignmentExpression);
+    }
+
+    function checkPatternParam(options, param) {
+        var i;
+        switch (param.type) {
+        case Syntax.Identifier:
+            validateParam(options, param, param.name);
+            break;
+        case Syntax.RestElement:
+            checkPatternParam(options, param.argument);
+            break;
+        case Syntax.AssignmentPattern:
+            checkPatternParam(options, param.left);
+            break;
+        case Syntax.ArrayPattern:
+            for (i = 0; i < param.elements.length; i++) {
+                if (param.elements[i] !== null) {
+                    checkPatternParam(options, param.elements[i]);
+                }
+            }
+            break;
+        case Syntax.YieldExpression:
+            break;
+        default:
+            assert(param.type === Syntax.ObjectPattern, 'Invalid type');
+            for (i = 0; i < param.properties.length; i++) {
+                checkPatternParam(options, param.properties[i].value);
+            }
+            break;
+        }
+    }
+    function reinterpretAsCoverFormalsList(expr) {
+        var i, len, param, params, defaults, defaultCount, options, token;
+
+        defaults = [];
+        defaultCount = 0;
+        params = [expr];
+
+        switch (expr.type) {
+        case Syntax.Identifier:
+            break;
+        case PlaceHolders.ArrowParameterPlaceHolder:
+            params = expr.params;
+            break;
+        default:
+            return null;
+        }
+
+        options = {
+            paramSet: {}
+        };
+
+        for (i = 0, len = params.length; i < len; i += 1) {
+            param = params[i];
+            switch (param.type) {
+            case Syntax.AssignmentPattern:
+                params[i] = param.left;
+                if (param.right.type === Syntax.YieldExpression) {
+                    if (param.right.argument) {
+                        throwUnexpectedToken(lookahead);
+                    }
+                    param.right.type = Syntax.Identifier;
+                    param.right.name = 'yield';
+                    delete param.right.argument;
+                    delete param.right.delegate;
+                }
+                defaults.push(param.right);
+                ++defaultCount;
+                checkPatternParam(options, param.left);
+                break;
+            default:
+                checkPatternParam(options, param);
+                params[i] = param;
+                defaults.push(null);
+                break;
+            }
+        }
+
+        if (strict || !state.allowYield) {
+            for (i = 0, len = params.length; i < len; i += 1) {
+                param = params[i];
+                if (param.type === Syntax.YieldExpression) {
+                    throwUnexpectedToken(lookahead);
+                }
+            }
+        }
+
+        if (options.message === Messages.StrictParamDupe) {
+            token = strict ? options.stricted : options.firstRestricted;
+            throwUnexpectedToken(token, options.message);
+        }
+
+        if (defaultCount === 0) {
+            defaults = [];
+        }
+
+        return {
+            params: params,
+            defaults: defaults,
+            stricted: options.stricted,
+            firstRestricted: options.firstRestricted,
+            message: options.message
+        };
+    }
+
+    function parseArrowFunctionExpression(options, node) {
+        var previousStrict, previousAllowYield, body;
+
+        if (hasLineTerminator) {
+            tolerateUnexpectedToken(lookahead);
+        }
+        expect('=>');
+
+        previousStrict = strict;
+        previousAllowYield = state.allowYield;
+        state.allowYield = true;
+
+        body = parseConciseBody();
+
+        if (strict && options.firstRestricted) {
+            throwUnexpectedToken(options.firstRestricted, options.message);
+        }
+        if (strict && options.stricted) {
+            tolerateUnexpectedToken(options.stricted, options.message);
+        }
+
+        strict = previousStrict;
+        state.allowYield = previousAllowYield;
+
+        return node.finishArrowFunctionExpression(options.params, options.defaults, body, body.type !== Syntax.BlockStatement);
+    }
+
+    // ECMA-262 14.4 Yield expression
+
+    function parseYieldExpression() {
+        var argument, expr, delegate, previousAllowYield;
+
+        argument = null;
+        expr = new Node();
+
+        expectKeyword('yield');
+
+        if (!hasLineTerminator) {
+            previousAllowYield = state.allowYield;
+            state.allowYield = false;
+            delegate = match('*');
+            if (delegate) {
+                lex();
+                argument = parseAssignmentExpression();
+            } else {
+                if (!match(';') && !match('}') && !match(')') && lookahead.type !== Token.EOF) {
+                    argument = parseAssignmentExpression();
+                }
+            }
+            state.allowYield = previousAllowYield;
+        }
+
+        return expr.finishYieldExpression(argument, delegate);
+    }
+
+    // ECMA-262 12.14 Assignment Operators
+
+    function parseAssignmentExpression() {
+        var token, expr, right, list, startToken;
+
+        startToken = lookahead;
+        token = lookahead;
+
+        if (!state.allowYield && matchKeyword('yield')) {
+            return parseYieldExpression();
+        }
+
+        expr = parseConditionalExpression();
+
+        if (expr.type === PlaceHolders.ArrowParameterPlaceHolder || match('=>')) {
+            isAssignmentTarget = isBindingElement = false;
+            list = reinterpretAsCoverFormalsList(expr);
+
+            if (list) {
+                firstCoverInitializedNameError = null;
+                return parseArrowFunctionExpression(list, new WrappingNode(startToken));
+            }
+
+            return expr;
+        }
+
+        if (matchAssign()) {
+            if (!isAssignmentTarget) {
+                tolerateError(Messages.InvalidLHSInAssignment);
+            }
+
+            // ECMA-262 12.1.1
+            if (strict && expr.type === Syntax.Identifier) {
+                if (isRestrictedWord(expr.name)) {
+                    tolerateUnexpectedToken(token, Messages.StrictLHSAssignment);
+                }
+                if (isStrictModeReservedWord(expr.name)) {
+                    tolerateUnexpectedToken(token, Messages.StrictReservedWord);
+                }
+            }
+
+            if (!match('=')) {
+                isAssignmentTarget = isBindingElement = false;
+            } else {
+                reinterpretExpressionAsPattern(expr);
+            }
+
+            token = lex();
+            right = isolateCoverGrammar(parseAssignmentExpression);
+            expr = new WrappingNode(startToken).finishAssignmentExpression(token.value, expr, right);
+            firstCoverInitializedNameError = null;
+        }
+
+        return expr;
+    }
+
+    // ECMA-262 12.15 Comma Operator
+
+    function parseExpression() {
+        var expr, startToken = lookahead, expressions;
+
+        expr = isolateCoverGrammar(parseAssignmentExpression);
+
+        if (match(',')) {
+            expressions = [expr];
+
+            while (startIndex < length) {
+                if (!match(',')) {
+                    break;
+                }
+                lex();
+                expressions.push(isolateCoverGrammar(parseAssignmentExpression));
+            }
+
+            expr = new WrappingNode(startToken).finishSequenceExpression(expressions);
+        }
+
+        return expr;
+    }
+
+    // ECMA-262 13.2 Block
+
+    function parseStatementListItem() {
+        if (lookahead.type === Token.Keyword) {
+            switch (lookahead.value) {
+            case 'export':
+                if (state.sourceType !== 'module') {
+                    tolerateUnexpectedToken(lookahead, Messages.IllegalExportDeclaration);
+                }
+                return parseExportDeclaration();
+            case 'import':
+                if (state.sourceType !== 'module') {
+                    tolerateUnexpectedToken(lookahead, Messages.IllegalImportDeclaration);
+                }
+                return parseImportDeclaration();
+            case 'const':
+            case 'let':
+                return parseLexicalDeclaration({inFor: false});
+            case 'function':
+                return parseFunctionDeclaration(new Node());
+            case 'class':
+                return parseClassDeclaration();
+            }
+        }
+
+        return parseStatement();
+    }
+
+    function parseStatementList() {
+        var list = [];
+        while (startIndex < length) {
+            if (match('}')) {
+                break;
+            }
+            list.push(parseStatementListItem());
+        }
+
+        return list;
+    }
+
+    function parseBlock() {
+        var block, node = new Node();
+
+        expect('{');
+
+        block = parseStatementList();
+
+        expect('}');
+
+        return node.finishBlockStatement(block);
+    }
+
+    // ECMA-262 13.3.2 Variable Statement
+
+    function parseVariableIdentifier(kind) {
+        var token, node = new Node();
+
+        token = lex();
+
+        if (token.type === Token.Keyword && token.value === 'yield') {
+            if (strict) {
+                tolerateUnexpectedToken(token, Messages.StrictReservedWord);
+            } if (!state.allowYield) {
+                throwUnexpectedToken(token);
+            }
+        } else if (token.type !== Token.Identifier) {
+            if (strict && token.type === Token.Keyword && isStrictModeReservedWord(token.value)) {
+                tolerateUnexpectedToken(token, Messages.StrictReservedWord);
+            } else {
+                if (strict || token.value !== 'let' || kind !== 'var') {
+                    throwUnexpectedToken(token);
+                }
+            }
+        } else if (state.sourceType === 'module' && token.type === Token.Identifier && token.value === 'await') {
+            tolerateUnexpectedToken(token);
+        }
+
+        return node.finishIdentifier(token.value);
+    }
+
+    function parseVariableDeclaration(options) {
+        var init = null, id, node = new Node(), params = [];
+
+        id = parsePattern(params, 'var');
+
+        // ECMA-262 12.2.1
+        if (strict && isRestrictedWord(id.name)) {
+            tolerateError(Messages.StrictVarName);
+        }
+
+        if (match('=')) {
+            lex();
+            init = isolateCoverGrammar(parseAssignmentExpression);
+        } else if (id.type !== Syntax.Identifier && !options.inFor) {
+            expect('=');
+        }
+
+        return node.finishVariableDeclarator(id, init);
+    }
+
+    function parseVariableDeclarationList(options) {
+        var list = [];
+
+        do {
+            list.push(parseVariableDeclaration({ inFor: options.inFor }));
+            if (!match(',')) {
+                break;
+            }
+            lex();
+        } while (startIndex < length);
+
+        return list;
+    }
+
+    function parseVariableStatement(node) {
+        var declarations;
+
+        expectKeyword('var');
+
+        declarations = parseVariableDeclarationList({ inFor: false });
+
+        consumeSemicolon();
+
+        return node.finishVariableDeclaration(declarations);
+    }
+
+    // ECMA-262 13.3.1 Let and Const Declarations
+
+    function parseLexicalBinding(kind, options) {
+        var init = null, id, node = new Node(), params = [];
+
+        id = parsePattern(params, kind);
+
+        // ECMA-262 12.2.1
+        if (strict && id.type === Syntax.Identifier && isRestrictedWord(id.name)) {
+            tolerateError(Messages.StrictVarName);
+        }
+
+        if (kind === 'const') {
+            if (!matchKeyword('in') && !matchContextualKeyword('of')) {
+                expect('=');
+                init = isolateCoverGrammar(parseAssignmentExpression);
+            }
+        } else if ((!options.inFor && id.type !== Syntax.Identifier) || match('=')) {
+            expect('=');
+            init = isolateCoverGrammar(parseAssignmentExpression);
+        }
+
+        return node.finishVariableDeclarator(id, init);
+    }
+
+    function parseBindingList(kind, options) {
+        var list = [];
+
+        do {
+            list.push(parseLexicalBinding(kind, options));
+            if (!match(',')) {
+                break;
+            }
+            lex();
+        } while (startIndex < length);
+
+        return list;
+    }
+
+    function parseLexicalDeclaration(options) {
+        var kind, declarations, node = new Node();
+
+        kind = lex().value;
+        assert(kind === 'let' || kind === 'const', 'Lexical declaration must be either let or const');
+
+        declarations = parseBindingList(kind, options);
+
+        consumeSemicolon();
+
+        return node.finishLexicalDeclaration(declarations, kind);
+    }
+
+    function parseRestElement(params) {
+        var param, node = new Node();
+
+        lex();
+
+        if (match('{')) {
+            throwError(Messages.ObjectPatternAsRestParameter);
+        }
+
+        params.push(lookahead);
+
+        param = parseVariableIdentifier();
+
+        if (match('=')) {
+            throwError(Messages.DefaultRestParameter);
+        }
+
+        if (!match(')')) {
+            throwError(Messages.ParameterAfterRestParameter);
+        }
+
+        return node.finishRestElement(param);
+    }
+
+    // ECMA-262 13.4 Empty Statement
+
+    function parseEmptyStatement(node) {
+        expect(';');
+        return node.finishEmptyStatement();
+    }
+
+    // ECMA-262 12.4 Expression Statement
+
+    function parseExpressionStatement(node) {
+        var expr = parseExpression();
+        consumeSemicolon();
+        return node.finishExpressionStatement(expr);
+    }
+
+    // ECMA-262 13.6 If statement
+
+    function parseIfStatement(node) {
+        var test, consequent, alternate;
+
+        expectKeyword('if');
+
+        expect('(');
+
+        test = parseExpression();
+
+        expect(')');
+
+        consequent = parseStatement();
+
+        if (matchKeyword('else')) {
+            lex();
+            alternate = parseStatement();
+        } else {
+            alternate = null;
+        }
+
+        return node.finishIfStatement(test, consequent, alternate);
+    }
+
+    // ECMA-262 13.7 Iteration Statements
+
+    function parseDoWhileStatement(node) {
+        var body, test, oldInIteration;
+
+        expectKeyword('do');
+
+        oldInIteration = state.inIteration;
+        state.inIteration = true;
+
+        body = parseStatement();
+
+        state.inIteration = oldInIteration;
+
+        expectKeyword('while');
+
+        expect('(');
+
+        test = parseExpression();
+
+        expect(')');
+
+        if (match(';')) {
+            lex();
+        }
+
+        return node.finishDoWhileStatement(body, test);
+    }
+
+    function parseWhileStatement(node) {
+        var test, body, oldInIteration;
+
+        expectKeyword('while');
+
+        expect('(');
+
+        test = parseExpression();
+
+        expect(')');
+
+        oldInIteration = state.inIteration;
+        state.inIteration = true;
+
+        body = parseStatement();
+
+        state.inIteration = oldInIteration;
+
+        return node.finishWhileStatement(test, body);
+    }
+
+    function parseForStatement(node) {
+        var init, forIn, initSeq, initStartToken, test, update, left, right, kind, declarations,
+            body, oldInIteration, previousAllowIn = state.allowIn;
+
+        init = test = update = null;
+        forIn = true;
+
+        expectKeyword('for');
+
+        expect('(');
+
+        if (match(';')) {
+            lex();
+        } else {
+            if (matchKeyword('var')) {
+                init = new Node();
+                lex();
+
+                state.allowIn = false;
+                declarations = parseVariableDeclarationList({ inFor: true });
+                state.allowIn = previousAllowIn;
+
+                if (declarations.length === 1 && matchKeyword('in')) {
+                    init = init.finishVariableDeclaration(declarations);
+                    lex();
+                    left = init;
+                    right = parseExpression();
+                    init = null;
+                } else if (declarations.length === 1 && declarations[0].init === null && matchContextualKeyword('of')) {
+                    init = init.finishVariableDeclaration(declarations);
+                    lex();
+                    left = init;
+                    right = parseAssignmentExpression();
+                    init = null;
+                    forIn = false;
+                } else {
+                    init = init.finishVariableDeclaration(declarations);
+                    expect(';');
+                }
+            } else if (matchKeyword('const') || matchKeyword('let')) {
+                init = new Node();
+                kind = lex().value;
+
+                state.allowIn = false;
+                declarations = parseBindingList(kind, {inFor: true});
+                state.allowIn = previousAllowIn;
+
+                if (declarations.length === 1 && declarations[0].init === null && matchKeyword('in')) {
+                    init = init.finishLexicalDeclaration(declarations, kind);
+                    lex();
+                    left = init;
+                    right = parseExpression();
+                    init = null;
+                } else if (declarations.length === 1 && declarations[0].init === null && matchContextualKeyword('of')) {
+                    init = init.finishLexicalDeclaration(declarations, kind);
+                    lex();
+                    left = init;
+                    right = parseAssignmentExpression();
+                    init = null;
+                    forIn = false;
+                } else {
+                    consumeSemicolon();
+                    init = init.finishLexicalDeclaration(declarations, kind);
+                }
+            } else {
+                initStartToken = lookahead;
+                state.allowIn = false;
+                init = inheritCoverGrammar(parseAssignmentExpression);
+                state.allowIn = previousAllowIn;
+
+                if (matchKeyword('in')) {
+                    if (!isAssignmentTarget) {
+                        tolerateError(Messages.InvalidLHSInForIn);
+                    }
+
+                    lex();
+                    reinterpretExpressionAsPattern(init);
+                    left = init;
+                    right = parseExpression();
+                    init = null;
+                } else if (matchContextualKeyword('of')) {
+                    if (!isAssignmentTarget) {
+                        tolerateError(Messages.InvalidLHSInForLoop);
+                    }
+
+                    lex();
+                    reinterpretExpressionAsPattern(init);
+                    left = init;
+                    right = parseAssignmentExpression();
+                    init = null;
+                    forIn = false;
+                } else {
+                    if (match(',')) {
+                        initSeq = [init];
+                        while (match(',')) {
+                            lex();
+                            initSeq.push(isolateCoverGrammar(parseAssignmentExpression));
+                        }
+                        init = new WrappingNode(initStartToken).finishSequenceExpression(initSeq);
+                    }
+                    expect(';');
+                }
+            }
+        }
+
+        if (typeof left === 'undefined') {
+
+            if (!match(';')) {
+                test = parseExpression();
+            }
+            expect(';');
+
+            if (!match(')')) {
+                update = parseExpression();
+            }
+        }
+
+        expect(')');
+
+        oldInIteration = state.inIteration;
+        state.inIteration = true;
+
+        body = isolateCoverGrammar(parseStatement);
+
+        state.inIteration = oldInIteration;
+
+        return (typeof left === 'undefined') ?
+                node.finishForStatement(init, test, update, body) :
+                forIn ? node.finishForInStatement(left, right, body) :
+                    node.finishForOfStatement(left, right, body);
+    }
+
+    // ECMA-262 13.8 The continue statement
+
+    function parseContinueStatement(node) {
+        var label = null, key;
+
+        expectKeyword('continue');
+
+        // Optimize the most common form: 'continue;'.
+        if (source.charCodeAt(startIndex) === 0x3B) {
+            lex();
+
+            if (!state.inIteration) {
+                throwError(Messages.IllegalContinue);
+            }
+
+            return node.finishContinueStatement(null);
+        }
+
+        if (hasLineTerminator) {
+            if (!state.inIteration) {
+                throwError(Messages.IllegalContinue);
+            }
+
+            return node.finishContinueStatement(null);
+        }
+
+        if (lookahead.type === Token.Identifier) {
+            label = parseVariableIdentifier();
+
+            key = '$' + label.name;
+            if (!Object.prototype.hasOwnProperty.call(state.labelSet, key)) {
+                throwError(Messages.UnknownLabel, label.name);
+            }
+        }
+
+        consumeSemicolon();
+
+        if (label === null && !state.inIteration) {
+            throwError(Messages.IllegalContinue);
+        }
+
+        return node.finishContinueStatement(label);
+    }
+
+    // ECMA-262 13.9 The break statement
+
+    function parseBreakStatement(node) {
+        var label = null, key;
+
+        expectKeyword('break');
+
+        // Catch the very common case first: immediately a semicolon (U+003B).
+        if (source.charCodeAt(lastIndex) === 0x3B) {
+            lex();
+
+            if (!(state.inIteration || state.inSwitch)) {
+                throwError(Messages.IllegalBreak);
+            }
+
+            return node.finishBreakStatement(null);
+        }
+
+        if (hasLineTerminator) {
+            if (!(state.inIteration || state.inSwitch)) {
+                throwError(Messages.IllegalBreak);
+            }
+
+            return node.finishBreakStatement(null);
+        }
+
+        if (lookahead.type === Token.Identifier) {
+            label = parseVariableIdentifier();
+
+            key = '$' + label.name;
+            if (!Object.prototype.hasOwnProperty.call(state.labelSet, key)) {
+                throwError(Messages.UnknownLabel, label.name);
+            }
+        }
+
+        consumeSemicolon();
+
+        if (label === null && !(state.inIteration || state.inSwitch)) {
+            throwError(Messages.IllegalBreak);
+        }
+
+        return node.finishBreakStatement(label);
+    }
+
+    // ECMA-262 13.10 The return statement
+
+    function parseReturnStatement(node) {
+        var argument = null;
+
+        expectKeyword('return');
+
+        if (!state.inFunctionBody) {
+            tolerateError(Messages.IllegalReturn);
+        }
+
+        // 'return' followed by a space and an identifier is very common.
+        if (source.charCodeAt(lastIndex) === 0x20) {
+            if (isIdentifierStart(source.charCodeAt(lastIndex + 1))) {
+                argument = parseExpression();
+                consumeSemicolon();
+                return node.finishReturnStatement(argument);
+            }
+        }
+
+        if (hasLineTerminator) {
+            // HACK
+            return node.finishReturnStatement(null);
+        }
+
+        if (!match(';')) {
+            if (!match('}') && lookahead.type !== Token.EOF) {
+                argument = parseExpression();
+            }
+        }
+
+        consumeSemicolon();
+
+        return node.finishReturnStatement(argument);
+    }
+
+    // ECMA-262 13.11 The with statement
+
+    function parseWithStatement(node) {
+        var object, body;
+
+        if (strict) {
+            tolerateError(Messages.StrictModeWith);
+        }
+
+        expectKeyword('with');
+
+        expect('(');
+
+        object = parseExpression();
+
+        expect(')');
+
+        body = parseStatement();
+
+        return node.finishWithStatement(object, body);
+    }
+
+    // ECMA-262 13.12 The switch statement
+
+    function parseSwitchCase() {
+        var test, consequent = [], statement, node = new Node();
+
+        if (matchKeyword('default')) {
+            lex();
+            test = null;
+        } else {
+            expectKeyword('case');
+            test = parseExpression();
+        }
+        expect(':');
+
+        while (startIndex < length) {
+            if (match('}') || matchKeyword('default') || matchKeyword('case')) {
+                break;
+            }
+            statement = parseStatementListItem();
+            consequent.push(statement);
+        }
+
+        return node.finishSwitchCase(test, consequent);
+    }
+
+    function parseSwitchStatement(node) {
+        var discriminant, cases, clause, oldInSwitch, defaultFound;
+
+        expectKeyword('switch');
+
+        expect('(');
+
+        discriminant = parseExpression();
+
+        expect(')');
+
+        expect('{');
+
+        cases = [];
+
+        if (match('}')) {
+            lex();
+            return node.finishSwitchStatement(discriminant, cases);
+        }
+
+        oldInSwitch = state.inSwitch;
+        state.inSwitch = true;
+        defaultFound = false;
+
+        while (startIndex < length) {
+            if (match('}')) {
+                break;
+            }
+            clause = parseSwitchCase();
+            if (clause.test === null) {
+                if (defaultFound) {
+                    throwError(Messages.MultipleDefaultsInSwitch);
+                }
+                defaultFound = true;
+            }
+            cases.push(clause);
+        }
+
+        state.inSwitch = oldInSwitch;
+
+        expect('}');
+
+        return node.finishSwitchStatement(discriminant, cases);
+    }
+
+    // ECMA-262 13.14 The throw statement
+
+    function parseThrowStatement(node) {
+        var argument;
+
+        expectKeyword('throw');
+
+        if (hasLineTerminator) {
+            throwError(Messages.NewlineAfterThrow);
+        }
+
+        argument = parseExpression();
+
+        consumeSemicolon();
+
+        return node.finishThrowStatement(argument);
+    }
+
+    // ECMA-262 13.15 The try statement
+
+    function parseCatchClause() {
+        var param, params = [], paramMap = {}, key, i, body, node = new Node();
+
+        expectKeyword('catch');
+
+        expect('(');
+        if (match(')')) {
+            throwUnexpectedToken(lookahead);
+        }
+
+        param = parsePattern(params);
+        for (i = 0; i < params.length; i++) {
+            key = '$' + params[i].value;
+            if (Object.prototype.hasOwnProperty.call(paramMap, key)) {
+                tolerateError(Messages.DuplicateBinding, params[i].value);
+            }
+            paramMap[key] = true;
+        }
+
+        // ECMA-262 12.14.1
+        if (strict && isRestrictedWord(param.name)) {
+            tolerateError(Messages.StrictCatchVariable);
+        }
+
+        expect(')');
+        body = parseBlock();
+        return node.finishCatchClause(param, body);
+    }
+
+    function parseTryStatement(node) {
+        var block, handler = null, finalizer = null;
+
+        expectKeyword('try');
+
+        block = parseBlock();
+
+        if (matchKeyword('catch')) {
+            handler = parseCatchClause();
+        }
+
+        if (matchKeyword('finally')) {
+            lex();
+            finalizer = parseBlock();
+        }
+
+        if (!handler && !finalizer) {
+            throwError(Messages.NoCatchOrFinally);
+        }
+
+        return node.finishTryStatement(block, handler, finalizer);
+    }
+
+    // ECMA-262 13.16 The debugger statement
+
+    function parseDebuggerStatement(node) {
+        expectKeyword('debugger');
+
+        consumeSemicolon();
+
+        return node.finishDebuggerStatement();
+    }
+
+    // 13 Statements
+
+    function parseStatement() {
+        var type = lookahead.type,
+            expr,
+            labeledBody,
+            key,
+            node;
+
+        if (type === Token.EOF) {
+            throwUnexpectedToken(lookahead);
+        }
+
+        if (type === Token.Punctuator && lookahead.value === '{') {
+            return parseBlock();
+        }
+        isAssignmentTarget = isBindingElement = true;
+        node = new Node();
+
+        if (type === Token.Punctuator) {
+            switch (lookahead.value) {
+            case ';':
+                return parseEmptyStatement(node);
+            case '(':
+                return parseExpressionStatement(node);
+            default:
+                break;
+            }
+        } else if (type === Token.Keyword) {
+            switch (lookahead.value) {
+            case 'break':
+                return parseBreakStatement(node);
+            case 'continue':
+                return parseContinueStatement(node);
+            case 'debugger':
+                return parseDebuggerStatement(node);
+            case 'do':
+                return parseDoWhileStatement(node);
+            case 'for':
+                return parseForStatement(node);
+            case 'function':
+                return parseFunctionDeclaration(node);
+            case 'if':
+                return parseIfStatement(node);
+            case 'return':
+                return parseReturnStatement(node);
+            case 'switch':
+                return parseSwitchStatement(node);
+            case 'throw':
+                return parseThrowStatement(node);
+            case 'try':
+                return parseTryStatement(node);
+            case 'var':
+                return parseVariableStatement(node);
+            case 'while':
+                return parseWhileStatement(node);
+            case 'with':
+                return parseWithStatement(node);
+            default:
+                break;
+            }
+        }
+
+        expr = parseExpression();
+
+        // ECMA-262 12.12 Labelled Statements
+        if ((expr.type === Syntax.Identifier) && match(':')) {
+            lex();
+
+            key = '$' + expr.name;
+            if (Object.prototype.hasOwnProperty.call(state.labelSet, key)) {
+                throwError(Messages.Redeclaration, 'Label', expr.name);
+            }
+
+            state.labelSet[key] = true;
+            labeledBody = parseStatement();
+            delete state.labelSet[key];
+            return node.finishLabeledStatement(expr, labeledBody);
+        }
+
+        consumeSemicolon();
+
+        return node.finishExpressionStatement(expr);
+    }
+
+    // ECMA-262 14.1 Function Definition
+
+    function parseFunctionSourceElements() {
+        var statement, body = [], token, directive, firstRestricted,
+            oldLabelSet, oldInIteration, oldInSwitch, oldInFunctionBody, oldParenthesisCount,
+            node = new Node();
+
+        expect('{');
+
+        while (startIndex < length) {
+            if (lookahead.type !== Token.StringLiteral) {
+                break;
+            }
+            token = lookahead;
+
+            statement = parseStatementListItem();
+            body.push(statement);
+            if (statement.expression.type !== Syntax.Literal) {
+                // this is not directive
+                break;
+            }
+            directive = source.slice(token.start + 1, token.end - 1);
+            if (directive === 'use strict') {
+                strict = true;
+                if (firstRestricted) {
+                    tolerateUnexpectedToken(firstRestricted, Messages.StrictOctalLiteral);
+                }
+            } else {
+                if (!firstRestricted && token.octal) {
+                    firstRestricted = token;
+                }
+            }
+        }
+
+        oldLabelSet = state.labelSet;
+        oldInIteration = state.inIteration;
+        oldInSwitch = state.inSwitch;
+        oldInFunctionBody = state.inFunctionBody;
+        oldParenthesisCount = state.parenthesizedCount;
+
+        state.labelSet = {};
+        state.inIteration = false;
+        state.inSwitch = false;
+        state.inFunctionBody = true;
+        state.parenthesizedCount = 0;
+
+        while (startIndex < length) {
+            if (match('}')) {
+                break;
+            }
+            body.push(parseStatementListItem());
+        }
+
+        expect('}');
+
+        state.labelSet = oldLabelSet;
+        state.inIteration = oldInIteration;
+        state.inSwitch = oldInSwitch;
+        state.inFunctionBody = oldInFunctionBody;
+        state.parenthesizedCount = oldParenthesisCount;
+
+        return node.finishBlockStatement(body);
+    }
+
+    function validateParam(options, param, name) {
+        var key = '$' + name;
+        if (strict) {
+            if (isRestrictedWord(name)) {
+                options.stricted = param;
+                options.message = Messages.StrictParamName;
+            }
+            if (Object.prototype.hasOwnProperty.call(options.paramSet, key)) {
+                options.stricted = param;
+                options.message = Messages.StrictParamDupe;
+            }
+        } else if (!options.firstRestricted) {
+            if (isRestrictedWord(name)) {
+                options.firstRestricted = param;
+                options.message = Messages.StrictParamName;
+            } else if (isStrictModeReservedWord(name)) {
+                options.firstRestricted = param;
+                options.message = Messages.StrictReservedWord;
+            } else if (Object.prototype.hasOwnProperty.call(options.paramSet, key)) {
+                options.stricted = param;
+                options.message = Messages.StrictParamDupe;
+            }
+        }
+        options.paramSet[key] = true;
+    }
+
+    function parseParam(options) {
+        var token, param, params = [], i, def;
+
+        token = lookahead;
+        if (token.value === '...') {
+            param = parseRestElement(params);
+            validateParam(options, param.argument, param.argument.name);
+            options.params.push(param);
+            options.defaults.push(null);
+            return false;
+        }
+
+        param = parsePatternWithDefault(params);
+        for (i = 0; i < params.length; i++) {
+            validateParam(options, params[i], params[i].value);
+        }
+
+        if (param.type === Syntax.AssignmentPattern) {
+            def = param.right;
+            param = param.left;
+            ++options.defaultCount;
+        }
+
+        options.params.push(param);
+        options.defaults.push(def);
+
+        return !match(')');
+    }
+
+    function parseParams(firstRestricted) {
+        var options;
+
+        options = {
+            params: [],
+            defaultCount: 0,
+            defaults: [],
+            firstRestricted: firstRestricted
+        };
+
+        expect('(');
+
+        if (!match(')')) {
+            options.paramSet = {};
+            while (startIndex < length) {
+                if (!parseParam(options)) {
+                    break;
+                }
+                expect(',');
+            }
+        }
+
+        expect(')');
+
+        if (options.defaultCount === 0) {
+            options.defaults = [];
+        }
+
+        return {
+            params: options.params,
+            defaults: options.defaults,
+            stricted: options.stricted,
+            firstRestricted: options.firstRestricted,
+            message: options.message
+        };
+    }
+
+    function parseFunctionDeclaration(node, identifierIsOptional) {
+        var id = null, params = [], defaults = [], body, token, stricted, tmp, firstRestricted, message, previousStrict,
+            isGenerator, previousAllowYield;
+
+        previousAllowYield = state.allowYield;
+
+        expectKeyword('function');
+
+        isGenerator = match('*');
+        if (isGenerator) {
+            lex();
+        }
+
+        if (!identifierIsOptional || !match('(')) {
+            token = lookahead;
+            id = parseVariableIdentifier();
+            if (strict) {
+                if (isRestrictedWord(token.value)) {
+                    tolerateUnexpectedToken(token, Messages.StrictFunctionName);
+                }
+            } else {
+                if (isRestrictedWord(token.value)) {
+                    firstRestricted = token;
+                    message = Messages.StrictFunctionName;
+                } else if (isStrictModeReservedWord(token.value)) {
+                    firstRestricted = token;
+                    message = Messages.StrictReservedWord;
+                }
+            }
+        }
+
+        state.allowYield = !isGenerator;
+        tmp = parseParams(firstRestricted);
+        params = tmp.params;
+        defaults = tmp.defaults;
+        stricted = tmp.stricted;
+        firstRestricted = tmp.firstRestricted;
+        if (tmp.message) {
+            message = tmp.message;
+        }
+
+
+        previousStrict = strict;
+        body = parseFunctionSourceElements();
+        if (strict && firstRestricted) {
+            throwUnexpectedToken(firstRestricted, message);
+        }
+        if (strict && stricted) {
+            tolerateUnexpectedToken(stricted, message);
+        }
+
+        strict = previousStrict;
+        state.allowYield = previousAllowYield;
+
+        return node.finishFunctionDeclaration(id, params, defaults, body, isGenerator);
+    }
+
+    function parseFunctionExpression() {
+        var token, id = null, stricted, firstRestricted, message, tmp,
+            params = [], defaults = [], body, previousStrict, node = new Node(),
+            isGenerator, previousAllowYield;
+
+        previousAllowYield = state.allowYield;
+
+        expectKeyword('function');
+
+        isGenerator = match('*');
+        if (isGenerator) {
+            lex();
+        }
+
+        state.allowYield = !isGenerator;
+        if (!match('(')) {
+            token = lookahead;
+            id = (!strict && !isGenerator && matchKeyword('yield')) ? parseNonComputedProperty() : parseVariableIdentifier();
+            if (strict) {
+                if (isRestrictedWord(token.value)) {
+                    tolerateUnexpectedToken(token, Messages.StrictFunctionName);
+                }
+            } else {
+                if (isRestrictedWord(token.value)) {
+                    firstRestricted = token;
+                    message = Messages.StrictFunctionName;
+                } else if (isStrictModeReservedWord(token.value)) {
+                    firstRestricted = token;
+                    message = Messages.StrictReservedWord;
+                }
+            }
+        }
+
+        tmp = parseParams(firstRestricted);
+        params = tmp.params;
+        defaults = tmp.defaults;
+        stricted = tmp.stricted;
+        firstRestricted = tmp.firstRestricted;
+        if (tmp.message) {
+            message = tmp.message;
+        }
+
+        previousStrict = strict;
+        body = parseFunctionSourceElements();
+        if (strict && firstRestricted) {
+            throwUnexpectedToken(firstRestricted, message);
+        }
+        if (strict && stricted) {
+            tolerateUnexpectedToken(stricted, message);
+        }
+        strict = previousStrict;
+        state.allowYield = previousAllowYield;
+
+        return node.finishFunctionExpression(id, params, defaults, body, isGenerator);
+    }
+
+    // ECMA-262 14.5 Class Definitions
+
+    function parseClassBody() {
+        var classBody, token, isStatic, hasConstructor = false, body, method, computed, key;
+
+        classBody = new Node();
+
+        expect('{');
+        body = [];
+        while (!match('}')) {
+            if (match(';')) {
+                lex();
+            } else {
+                method = new Node();
+                token = lookahead;
+                isStatic = false;
+                computed = match('[');
+                if (match('*')) {
+                    lex();
+                } else {
+                    key = parseObjectPropertyKey();
+                    if (key.name === 'static' && (lookaheadPropertyName() || match('*'))) {
+                        token = lookahead;
+                        isStatic = true;
+                        computed = match('[');
+                        if (match('*')) {
+                            lex();
+                        } else {
+                            key = parseObjectPropertyKey();
+                        }
+                    }
+                }
+                method = tryParseMethodDefinition(token, key, computed, method);
+                if (method) {
+                    method['static'] = isStatic; // jscs:ignore requireDotNotation
+                    if (method.kind === 'init') {
+                        method.kind = 'method';
+                    }
+                    if (!isStatic) {
+                        if (!method.computed && (method.key.name || method.key.value.toString()) === 'constructor') {
+                            if (method.kind !== 'method' || !method.method || method.value.generator) {
+                                throwUnexpectedToken(token, Messages.ConstructorSpecialMethod);
+                            }
+                            if (hasConstructor) {
+                                throwUnexpectedToken(token, Messages.DuplicateConstructor);
+                            } else {
+                                hasConstructor = true;
+                            }
+                            method.kind = 'constructor';
+                        }
+                    } else {
+                        if (!method.computed && (method.key.name || method.key.value.toString()) === 'prototype') {
+                            throwUnexpectedToken(token, Messages.StaticPrototype);
+                        }
+                    }
+                    method.type = Syntax.MethodDefinition;
+                    delete method.method;
+                    delete method.shorthand;
+                    body.push(method);
+                } else {
+                    throwUnexpectedToken(lookahead);
+                }
+            }
+        }
+        lex();
+        return classBody.finishClassBody(body);
+    }
+
+    function parseClassDeclaration(identifierIsOptional) {
+        var id = null, superClass = null, classNode = new Node(), classBody, previousStrict = strict;
+        strict = true;
+
+        expectKeyword('class');
+
+        if (!identifierIsOptional || lookahead.type === Token.Identifier) {
+            id = parseVariableIdentifier();
+        }
+
+        if (matchKeyword('extends')) {
+            lex();
+            superClass = isolateCoverGrammar(parseLeftHandSideExpressionAllowCall);
+        }
+        classBody = parseClassBody();
+        strict = previousStrict;
+
+        return classNode.finishClassDeclaration(id, superClass, classBody);
+    }
+
+    function parseClassExpression() {
+        var id = null, superClass = null, classNode = new Node(), classBody, previousStrict = strict;
+        strict = true;
+
+        expectKeyword('class');
+
+        if (lookahead.type === Token.Identifier) {
+            id = parseVariableIdentifier();
+        }
+
+        if (matchKeyword('extends')) {
+            lex();
+            superClass = isolateCoverGrammar(parseLeftHandSideExpressionAllowCall);
+        }
+        classBody = parseClassBody();
+        strict = previousStrict;
+
+        return classNode.finishClassExpression(id, superClass, classBody);
+    }
+
+    // ECMA-262 15.2 Modules
+
+    function parseModuleSpecifier() {
+        var node = new Node();
+
+        if (lookahead.type !== Token.StringLiteral) {
+            throwError(Messages.InvalidModuleSpecifier);
+        }
+        return node.finishLiteral(lex());
+    }
+
+    // ECMA-262 15.2.3 Exports
+
+    function parseExportSpecifier() {
+        var exported, local, node = new Node(), def;
+        if (matchKeyword('default')) {
+            // export {default} from 'something';
+            def = new Node();
+            lex();
+            local = def.finishIdentifier('default');
+        } else {
+            local = parseVariableIdentifier();
+        }
+        if (matchContextualKeyword('as')) {
+            lex();
+            exported = parseNonComputedProperty();
+        }
+        return node.finishExportSpecifier(local, exported);
+    }
+
+    function parseExportNamedDeclaration(node) {
+        var declaration = null,
+            isExportFromIdentifier,
+            src = null, specifiers = [];
+
+        // non-default export
+        if (lookahead.type === Token.Keyword) {
+            // covers:
+            // export var f = 1;
+            switch (lookahead.value) {
+                case 'let':
+                case 'const':
+                case 'var':
+                case 'class':
+                case 'function':
+                    declaration = parseStatementListItem();
+                    return node.finishExportNamedDeclaration(declaration, specifiers, null);
+            }
+        }
+
+        expect('{');
+        while (!match('}')) {
+            isExportFromIdentifier = isExportFromIdentifier || matchKeyword('default');
+            specifiers.push(parseExportSpecifier());
+            if (!match('}')) {
+                expect(',');
+                if (match('}')) {
+                    break;
+                }
+            }
+        }
+        expect('}');
+
+        if (matchContextualKeyword('from')) {
+            // covering:
+            // export {default} from 'foo';
+            // export {foo} from 'foo';
+            lex();
+            src = parseModuleSpecifier();
+            consumeSemicolon();
+        } else if (isExportFromIdentifier) {
+            // covering:
+            // export {default}; // missing fromClause
+            throwError(lookahead.value ?
+                    Messages.UnexpectedToken : Messages.MissingFromClause, lookahead.value);
+        } else {
+            // cover
+            // export {foo};
+            consumeSemicolon();
+        }
+        return node.finishExportNamedDeclaration(declaration, specifiers, src);
+    }
+
+    function parseExportDefaultDeclaration(node) {
+        var declaration = null,
+            expression = null;
+
+        // covers:
+        // export default ...
+        expectKeyword('default');
+
+        if (matchKeyword('function')) {
+            // covers:
+            // export default function foo () {}
+            // export default function () {}
+            declaration = parseFunctionDeclaration(new Node(), true);
+            return node.finishExportDefaultDeclaration(declaration);
+        }
+        if (matchKeyword('class')) {
+            declaration = parseClassDeclaration(true);
+            return node.finishExportDefaultDeclaration(declaration);
+        }
+
+        if (matchContextualKeyword('from')) {
+            throwError(Messages.UnexpectedToken, lookahead.value);
+        }
+
+        // covers:
+        // export default {};
+        // export default [];
+        // export default (1 + 2);
+        if (match('{')) {
+            expression = parseObjectInitializer();
+        } else if (match('[')) {
+            expression = parseArrayInitializer();
+        } else {
+            expression = parseAssignmentExpression();
+        }
+        consumeSemicolon();
+        return node.finishExportDefaultDeclaration(expression);
+    }
+
+    function parseExportAllDeclaration(node) {
+        var src;
+
+        // covers:
+        // export * from 'foo';
+        expect('*');
+        if (!matchContextualKeyword('from')) {
+            throwError(lookahead.value ?
+                    Messages.UnexpectedToken : Messages.MissingFromClause, lookahead.value);
+        }
+        lex();
+        src = parseModuleSpecifier();
+        consumeSemicolon();
+
+        return node.finishExportAllDeclaration(src);
+    }
+
+    function parseExportDeclaration() {
+        var node = new Node();
+        if (state.inFunctionBody) {
+            throwError(Messages.IllegalExportDeclaration);
+        }
+
+        expectKeyword('export');
+
+        if (matchKeyword('default')) {
+            return parseExportDefaultDeclaration(node);
+        }
+        if (match('*')) {
+            return parseExportAllDeclaration(node);
+        }
+        return parseExportNamedDeclaration(node);
+    }
+
+    // ECMA-262 15.2.2 Imports
+
+    function parseImportSpecifier() {
+        // import {<foo as bar>} ...;
+        var local, imported, node = new Node();
+
+        imported = parseNonComputedProperty();
+        if (matchContextualKeyword('as')) {
+            lex();
+            local = parseVariableIdentifier();
+        }
+
+        return node.finishImportSpecifier(local, imported);
+    }
+
+    function parseNamedImports() {
+        var specifiers = [];
+        // {foo, bar as bas}
+        expect('{');
+        while (!match('}')) {
+            specifiers.push(parseImportSpecifier());
+            if (!match('}')) {
+                expect(',');
+                if (match('}')) {
+                    break;
+                }
+            }
+        }
+        expect('}');
+        return specifiers;
+    }
+
+    function parseImportDefaultSpecifier() {
+        // import <foo> ...;
+        var local, node = new Node();
+
+        local = parseNonComputedProperty();
+
+        return node.finishImportDefaultSpecifier(local);
+    }
+
+    function parseImportNamespaceSpecifier() {
+        // import <* as foo> ...;
+        var local, node = new Node();
+
+        expect('*');
+        if (!matchContextualKeyword('as')) {
+            throwError(Messages.NoAsAfterImportNamespace);
+        }
+        lex();
+        local = parseNonComputedProperty();
+
+        return node.finishImportNamespaceSpecifier(local);
+    }
+
+    function parseImportDeclaration() {
+        var specifiers = [], src, node = new Node();
+
+        if (state.inFunctionBody) {
+            throwError(Messages.IllegalImportDeclaration);
+        }
+
+        expectKeyword('import');
+
+        if (lookahead.type === Token.StringLiteral) {
+            // import 'foo';
+            src = parseModuleSpecifier();
+        } else {
+
+            if (match('{')) {
+                // import {bar}
+                specifiers = specifiers.concat(parseNamedImports());
+            } else if (match('*')) {
+                // import * as foo
+                specifiers.push(parseImportNamespaceSpecifier());
+            } else if (isIdentifierName(lookahead) && !matchKeyword('default')) {
+                // import foo
+                specifiers.push(parseImportDefaultSpecifier());
+                if (match(',')) {
+                    lex();
+                    if (match('*')) {
+                        // import foo, * as foo
+                        specifiers.push(parseImportNamespaceSpecifier());
+                    } else if (match('{')) {
+                        // import foo, {bar}
+                        specifiers = specifiers.concat(parseNamedImports());
+                    } else {
+                        throwUnexpectedToken(lookahead);
+                    }
+                }
+            } else {
+                throwUnexpectedToken(lex());
+            }
+
+            if (!matchContextualKeyword('from')) {
+                throwError(lookahead.value ?
+                        Messages.UnexpectedToken : Messages.MissingFromClause, lookahead.value);
+            }
+            lex();
+            src = parseModuleSpecifier();
+        }
+
+        consumeSemicolon();
+        return node.finishImportDeclaration(specifiers, src);
+    }
+
+    // ECMA-262 15.1 Scripts
+
+    function parseScriptBody() {
+        var statement, body = [], token, directive, firstRestricted;
+
+        while (startIndex < length) {
+            token = lookahead;
+            if (token.type !== Token.StringLiteral) {
+                break;
+            }
+
+            statement = parseStatementListItem();
+            body.push(statement);
+            if (statement.expression.type !== Syntax.Literal) {
+                // this is not directive
+                break;
+            }
+            directive = source.slice(token.start + 1, token.end - 1);
+            if (directive === 'use strict') {
+                strict = true;
+                if (firstRestricted) {
+                    tolerateUnexpectedToken(firstRestricted, Messages.StrictOctalLiteral);
+                }
+            } else {
+                if (!firstRestricted && token.octal) {
+                    firstRestricted = token;
+                }
+            }
+        }
+
+        while (startIndex < length) {
+            statement = parseStatementListItem();
+            /* istanbul ignore if */
+            if (typeof statement === 'undefined') {
+                break;
+            }
+            body.push(statement);
+        }
+        return body;
+    }
+
+    function parseProgram() {
+        var body, node;
+
+        peek();
+        node = new Node();
+
+        body = parseScriptBody();
+        return node.finishProgram(body, state.sourceType);
+    }
+
+    function filterTokenLocation() {
+        var i, entry, token, tokens = [];
+
+        for (i = 0; i < extra.tokens.length; ++i) {
+            entry = extra.tokens[i];
+            token = {
+                type: entry.type,
+                value: entry.value
+            };
+            if (entry.regex) {
+                token.regex = {
+                    pattern: entry.regex.pattern,
+                    flags: entry.regex.flags
+                };
+            }
+            if (extra.range) {
+                token.range = entry.range;
+            }
+            if (extra.loc) {
+                token.loc = entry.loc;
+            }
+            tokens.push(token);
+        }
+
+        extra.tokens = tokens;
+    }
+
+    function tokenize(code, options) {
+        var toString,
+            tokens;
+
+        toString = String;
+        if (typeof code !== 'string' && !(code instanceof String)) {
+            code = toString(code);
+        }
+
+        source = code;
+        index = 0;
+        lineNumber = (source.length > 0) ? 1 : 0;
+        lineStart = 0;
+        startIndex = index;
+        startLineNumber = lineNumber;
+        startLineStart = lineStart;
+        length = source.length;
+        lookahead = null;
+        state = {
+            allowIn: true,
+            allowYield: true,
+            labelSet: {},
+            inFunctionBody: false,
+            inIteration: false,
+            inSwitch: false,
+            lastCommentStart: -1,
+            curlyStack: []
+        };
+
+        extra = {};
+
+        // Options matching.
+        options = options || {};
+
+        // Of course we collect tokens here.
+        options.tokens = true;
+        extra.tokens = [];
+        extra.tokenize = true;
+        // The following two fields are necessary to compute the Regex tokens.
+        extra.openParenToken = -1;
+        extra.openCurlyToken = -1;
+
+        extra.range = (typeof options.range === 'boolean') && options.range;
+        extra.loc = (typeof options.loc === 'boolean') && options.loc;
+
+        if (typeof options.comment === 'boolean' && options.comment) {
+            extra.comments = [];
+        }
+        if (typeof options.tolerant === 'boolean' && options.tolerant) {
+            extra.errors = [];
+        }
+
+        try {
+            peek();
+            if (lookahead.type === Token.EOF) {
+                return extra.tokens;
+            }
+
+            lex();
+            while (lookahead.type !== Token.EOF) {
+                try {
+                    lex();
+                } catch (lexError) {
+                    if (extra.errors) {
+                        recordError(lexError);
+                        // We have to break on the first error
+                        // to avoid infinite loops.
+                        break;
+                    } else {
+                        throw lexError;
+                    }
+                }
+            }
+
+            filterTokenLocation();
+            tokens = extra.tokens;
+            if (typeof extra.comments !== 'undefined') {
+                tokens.comments = extra.comments;
+            }
+            if (typeof extra.errors !== 'undefined') {
+                tokens.errors = extra.errors;
+            }
+        } catch (e) {
+            throw e;
+        } finally {
+            extra = {};
+        }
+        return tokens;
+    }
+
+    function parse(code, options) {
+        var program, toString;
+
+        toString = String;
+        if (typeof code !== 'string' && !(code instanceof String)) {
+            code = toString(code);
+        }
+
+        source = code;
+        index = 0;
+        lineNumber = (source.length > 0) ? 1 : 0;
+        lineStart = 0;
+        startIndex = index;
+        startLineNumber = lineNumber;
+        startLineStart = lineStart;
+        length = source.length;
+        lookahead = null;
+        state = {
+            allowIn: true,
+            allowYield: true,
+            labelSet: {},
+            inFunctionBody: false,
+            inIteration: false,
+            inSwitch: false,
+            lastCommentStart: -1,
+            curlyStack: [],
+            sourceType: 'script'
+        };
+        strict = false;
+
+        extra = {};
+        if (typeof options !== 'undefined') {
+            extra.range = (typeof options.range === 'boolean') && options.range;
+            extra.loc = (typeof options.loc === 'boolean') && options.loc;
+            extra.attachComment = (typeof options.attachComment === 'boolean') && options.attachComment;
+
+            if (extra.loc && options.source !== null && options.source !== undefined) {
+                extra.source = toString(options.source);
+            }
+
+            if (typeof options.tokens === 'boolean' && options.tokens) {
+                extra.tokens = [];
+            }
+            if (typeof options.comment === 'boolean' && options.comment) {
+                extra.comments = [];
+            }
+            if (typeof options.tolerant === 'boolean' && options.tolerant) {
+                extra.errors = [];
+            }
+            if (extra.attachComment) {
+                extra.range = true;
+                extra.comments = [];
+                extra.bottomRightStack = [];
+                extra.trailingComments = [];
+                extra.leadingComments = [];
+            }
+            if (options.sourceType === 'module') {
+                // very restrictive condition for now
+                state.sourceType = options.sourceType;
+                strict = true;
+            }
+        }
+
+        try {
+            program = parseProgram();
+            if (typeof extra.comments !== 'undefined') {
+                program.comments = extra.comments;
+            }
+            if (typeof extra.tokens !== 'undefined') {
+                filterTokenLocation();
+                program.tokens = extra.tokens;
+            }
+            if (typeof extra.errors !== 'undefined') {
+                program.errors = extra.errors;
+            }
+        } catch (e) {
+            throw e;
+        } finally {
+            extra = {};
+        }
+
+        return program;
+    }
+
+    // Sync with *.json manifests.
+    exports.version = '2.6.0';
+
+    exports.tokenize = tokenize;
+
+    exports.parse = parse;
+
+    // Deep copy.
+    /* istanbul ignore next */
+    exports.Syntax = (function () {
+        var name, types = {};
+
+        if (typeof Object.create === 'function') {
+            types = Object.create(null);
+        }
+
+        for (name in Syntax) {
+            if (Syntax.hasOwnProperty(name)) {
+                types[name] = Syntax[name];
+            }
+        }
+
+        if (typeof Object.freeze === 'function') {
+            Object.freeze(types);
+        }
+
+        return types;
+    }());
+
+}));
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/generator/node_modules/esprima/package.json b/generator/node_modules/esprima/package.json
new file mode 100644
index 0000000..3feed55
--- /dev/null
+++ b/generator/node_modules/esprima/package.json
@@ -0,0 +1,109 @@
+{
+  "name": "esprima",
+  "description": "ECMAScript parsing infrastructure for multipurpose analysis",
+  "homepage": "http://esprima.org",
+  "main": "esprima.js",
+  "bin": {
+    "esparse": "./bin/esparse.js",
+    "esvalidate": "./bin/esvalidate.js"
+  },
+  "version": "2.6.0",
+  "files": [
+    "bin",
+    "unit-tests.js",
+    "esprima.js"
+  ],
+  "engines": {
+    "node": ">=0.10.0"
+  },
+  "author": {
+    "name": "Ariya Hidayat",
+    "email": "ariya.hidayat@gmail.com"
+  },
+  "maintainers": [
+    {
+      "name": "ariya",
+      "email": "ariya.hidayat@gmail.com"
+    }
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/jquery/esprima.git"
+  },
+  "bugs": {
+    "url": "https://github.com/jquery/esprima/issues"
+  },
+  "license": "BSD-2-Clause",
+  "devDependencies": {
+    "codecov.io": "~0.1.6",
+    "escomplex-js": "1.2.0",
+    "eslint": "~1.3.1",
+    "everything.js": "~1.0.3",
+    "glob": "^5.0.14",
+    "istanbul": "~0.3.19",
+    "jscs": "~2.1.1",
+    "json-diff": "~0.3.1",
+    "karma": "^0.13.3",
+    "karma-chrome-launcher": "^0.2.0",
+    "karma-detect-browsers": "^2.0.1",
+    "karma-firefox-launcher": "^0.1.6",
+    "karma-ie-launcher": "^0.2.0",
+    "karma-mocha": "^0.2.0",
+    "karma-safari-launcher": "^0.1.1",
+    "lodash": "^3.10.0",
+    "mocha": "^2.2.5",
+    "node-tick-processor": "~0.0.2",
+    "regenerate": "~0.6.2",
+    "temp": "~0.8.3",
+    "unicode-7.0.0": "~0.1.5"
+  },
+  "keywords": [
+    "ast",
+    "ecmascript",
+    "javascript",
+    "parser",
+    "syntax"
+  ],
+  "scripts": {
+    "check-version": "node test/check-version.js",
+    "jscs": "jscs -p crockford esprima.js && jscs -p crockford test/*.js",
+    "eslint": "node node_modules/eslint/bin/eslint.js -c .lintrc esprima.js",
+    "complexity": "node test/check-complexity.js",
+    "static-analysis": "npm run check-version && npm run jscs && npm run eslint && npm run complexity",
+    "unit-tests": "node test/unit-tests.js",
+    "grammar-tests": "node test/grammar-tests.js",
+    "regression-tests": "node test/regression-tests.js",
+    "tests": "npm run generate-fixtures && npm run unit-tests && npm run grammar-tests && npm run regression-tests",
+    "generate-fixtures": "node tools/generate-fixtures.js",
+    "browser-tests": "npm run generate-fixtures && cd test && karma start --single-run",
+    "analyze-coverage": "istanbul cover test/unit-tests.js",
+    "check-coverage": "istanbul check-coverage --statement 100 --branch 100 --function 100",
+    "dynamic-analysis": "npm run analyze-coverage && npm run check-coverage",
+    "test": "npm run tests && npm run static-analysis && npm run dynamic-analysis",
+    "profile": "node --prof test/profile.js && mv isolate*.log v8.log && node-tick-processor",
+    "benchmark": "node test/benchmarks.js",
+    "benchmark-quick": "node test/benchmarks.js quick",
+    "codecov": "istanbul report cobertura && codecov < ./coverage/cobertura-coverage.xml",
+    "downstream": "node test/downstream.js",
+    "travis": "npm test",
+    "circleci": "npm test && npm run codecov && npm run downstream",
+    "appveyor": "npm run tests && npm run browser-tests && npm run dynamic-analysis",
+    "generate-regex": "node tools/generate-identifier-regex.js"
+  },
+  "gitHead": "72bb2191ffd9d4f2053cab511da0b27b882a5a48",
+  "_id": "esprima@2.6.0",
+  "_shasum": "eddae7cccd7c4d6f3058b7f3823718aaaef7527f",
+  "_from": "esprima@*",
+  "_npmVersion": "2.11.2",
+  "_nodeVersion": "0.12.5",
+  "_npmUser": {
+    "name": "ariya",
+    "email": "ariya.hidayat@gmail.com"
+  },
+  "dist": {
+    "shasum": "eddae7cccd7c4d6f3058b7f3823718aaaef7527f",
+    "tarball": "http://registry.npmjs.org/esprima/-/esprima-2.6.0.tgz"
+  },
+  "directories": {},
+  "_resolved": "https://registry.npmjs.org/esprima/-/esprima-2.6.0.tgz"
+}
diff --git a/generator/tests/js/calcunlog.js b/generator/tests/js/calcunlog.js
new file mode 100644
index 0000000..a8daf65
--- /dev/null
+++ b/generator/tests/js/calcunlog.js
@@ -0,0 +1,74 @@
+Stack = {
+
+is_empty: function (s) {
+             return s === {type: "N"};
+           },
+           
+push: function (x, stack) {
+  return {type: "C", value: x, stack: stack};
+},
+
+pop: function (stack) {
+  return (function () {
+    switch (stack.type) {
+    case "C": var x = stack.value, xs = stack.stack;
+              return x;
+    case "K": var x = stack.value, xs = stack.stack;
+              return x;
+    case "B": 
+              return stuck("Empty list");
+    case "N": 
+              return stuck("Empty list");
+    }
+  }())
+  ;
+},
+
+}
+var eval_ = function (expr) {
+     return (function () {
+       switch (expr.type) {
+       case "Const": var n = expr.value;
+                     return n;
+       case "Add": var ls = expr.left, rs = expr.right;
+                   return eval_(ls) + eval_(rs);
+       case "Sub": var ls = expr.left, rs = expr.right;
+                   return eval_(ls) - eval_(rs);
+       case "Mul": var ls = expr.left, rs = expr.right;
+                   return eval_(ls) * eval_(rs);
+       case "Div": var ls = expr.left, rs = expr.right;
+                   return eval_(ls) / eval_(rs);
+       }
+     }())
+     ;
+   };
+   
+var print_expr = function (expr) {
+  return (function () {
+    switch (expr.type) {
+    case "Const": var n = expr.value;
+                  return to_string(n);
+    case "Add": var ls = expr.left, rs = expr.right;
+                return "(" + print_expr(ls) + ")" + " + " + print_expr(rs);
+    case "Sub": var ls = expr.left, rs = expr.right;
+                return "(" + print_expr(ls) + ")" + " - " + print_expr(rs);
+    case "Mul": var ls = expr.left, rs = expr.right;
+                return "(" + print_expr(ls) + ")" + " * " + print_expr(rs);
+    case "Div": var ls = expr.left, rs = expr.right;
+                return "(" + print_expr(ls) + ")" + " / " + print_expr(rs);
+    }
+  }())
+  ;
+};
+
+var f = (function () {
+  var bli = {type: "Stack.C", value: 1, stack: {type: "Stack.N"}};
+  
+  return (function () {
+    var source = parse("((1972 / 29) / 2) + 8");
+    
+    return print(print_expr(source) + " = " + to_string(eval_(source)));
+  }())
+  ;
+}())
+;
diff --git a/generator/tests/js/letunlog.js b/generator/tests/js/letunlog.js
new file mode 100644
index 0000000..a1649a0
--- /dev/null
+++ b/generator/tests/js/letunlog.js
@@ -0,0 +1,34 @@
+
+(function () {
+  var abr = 1;
+  
+var bli = 4;
+   
+  return (function () {
+    
+      if (true) {
+      return  abr;
+      } else {
+      return  bli;
+      }
+  })();}())var app = function (x) {
+             return x;
+           };
+           var app2 = function (x) {
+             return x;
+           };
+           
+var affiche = function (x) {
+  return (function () {
+    switch (x.type) {
+    case "As": 
+               return "As";
+    case "Petite": var n = x.petite;
+                   return "Petite";
+    }
+  }())
+  ;
+};
+var pet = {type: "Petite", petite: 5};
+
+var cinq = 5;
diff --git a/generator/tests/js/mylistunlog.js b/generator/tests/js/mylistunlog.js
new file mode 100644
index 0000000..fc996bf
--- /dev/null
+++ b/generator/tests/js/mylistunlog.js
@@ -0,0 +1,163 @@
+
+var incr = function (i) {
+   return add(i, 1);
+ };
+ 
+var head = function (d, l) {
+  return (function () {
+    switch (l.type) {
+    case "Nil": 
+                return d;
+    case "Cons": var x = l.hd, xs = l.tl;
+                 return x;
+    }
+  }())
+  ;
+};
+
+var tail = function (d, l) {
+  return (function () {
+    switch (l.type) {
+    case "Nil": 
+                return d;
+    case "Cons": var x = l.hd, xs = l.tl;
+                 return xs;
+    }
+  }())
+  ;
+};
+
+var init = function (l) {
+  return (function () {
+    switch (l.type) {
+    case "Nil": 
+                return {type: "Nil"};
+    case "Cons": var x = l.hd, xs = l.tl;
+                 return xs;
+    }
+  }())
+  ;
+};
+
+var last = function (l) {
+  return (function () {
+    switch (l.type) {
+    case "Nil": 
+                return {type: "Nil"};
+    case "Cons": var x = l.hd, xs = l.tl;
+                 return (function () {
+                   switch (xs.type) {
+                   case "Nil": 
+                               return x;
+                   default: 
+                            return last(xs);
+                   }
+                 }())
+                 ;
+    }
+  }())
+  ;
+};
+
+var fold_left = function (f, acc, l) {
+  return (function () {
+    switch (l.type) {
+    case "Nil": 
+                return acc;
+    case "Cons": var x = l.hd, xs = l.tl;
+                 return fold_left(f, f(acc, x), xs);
+    }
+  }())
+  ;
+};
+
+var fold_right = function (f, l, acc) {
+  return (function () {
+    switch (l.type) {
+    case "Nil": 
+                return acc;
+    case "Cons": var x = l.hd, xs = l.tl;
+                 return f(fold_right(f, xs, acc), x);
+    }
+  }())
+  ;
+};
+
+var rev_map = function (f, l) {
+  return fold_left(function (acc, x) {
+    return {type: "Cons", hd: f(x), tl: acc};
+  }, {type: "Nil"}, l);
+};
+
+var map = function (f, l) {
+  return fold_right(function (acc, x) {
+    return {type: "Cons", hd: f(x), tl: acc};
+  }, l, {type: "Nil"});
+};
+
+var rev = function (l) {
+  return fold_left(function (acc, x) {
+    return {type: "Cons", hd: x, tl: acc};
+  }, {type: "Nil"}, l);
+};
+
+var length = function (l) {
+  return fold_left(function (acc, x) {
+    return incr(acc);
+  }, 0, l);
+};
+
+var range = function (i, j, acc) {
+  return (function () {
+    
+      if (i <= j) {
+      return  range(incr(i), j, {type: "Cons", hd: i, tl: acc});
+      } else {
+      return  acc;
+      }
+  })();
+};
+var list0 = {type: "Nil"};
+var list1 = range(0, 1, {type: "Nil"});
+var list2 = range(1, 5, {type: "Nil"});
+var sqr = function (x) {
+  return mul(x, x);
+};
+
+var print_list = function (l) {
+  return (function () {
+    var aux = function (acc, l) {
+      return (function () {
+        switch (l.type) {
+        case "Nil": 
+                    return acc;
+        case "Cons": var x = l.hd, xs = l.tl;
+                     return print(xs),
+                     (function () {
+                       
+                         if (xs === {type: "Nil"}) {
+                         return  aux(x + acc, xs);
+                         } else {
+                         return  aux(x + "," + acc, xs);
+                         }
+                     })();
+        }
+      }())
+      ;
+    };
+    
+    return "[" + aux("", rev(l)) + "]";
+  }())
+  ;
+};
+(function () {
+  var f = 1;
+  
+  return print(length(list0)),
+  print(length(list1)),
+  print(length(list2)),
+  print(print_list(map(function (x) {
+    return x * x;
+  }, list0))),
+  print(print_list(map(sqr, list1))),
+  print(print_list(map(sqr, list2)));}())
diff --git a/generator/tests/js/recordsunlog.js b/generator/tests/js/recordsunlog.js
new file mode 100644
index 0000000..5de5da4
--- /dev/null
+++ b/generator/tests/js/recordsunlog.js
@@ -0,0 +1,7 @@
+
+var boss = {
+                name: "smith",
+              status: "boss",
+              age: 48
+ };
+ 
\ No newline at end of file
diff --git a/generator/tests/js/stackunlog.js b/generator/tests/js/stackunlog.js
new file mode 100644
index 0000000..3fba818
--- /dev/null
+++ b/generator/tests/js/stackunlog.js
@@ -0,0 +1,24 @@
+
+var is_empty = function (s) {
+   return s === {type: "N"};
+ };
+ 
+var push = function (x, stack) {
+  return {type: "C", value: x, stack: stack};
+};
+
+var pop = function (stack) {
+  return (function () {
+    switch (stack.type) {
+    case "C": var x = stack.value, xs = stack.stack;
+              return x;
+    case "K": var x = stack.value, xs = stack.stack;
+              return x;
+    case "B": 
+              return stuck("Empty list");
+    case "N": 
+              return stuck("Empty list");
+    }
+  }())
+  ;
+};
-- 
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