!function(e){if("object"==typeof exports&&"undefined"!=typeof module)module.exports=e();else if("function"==typeof define&&define.amd)define([],e);else{var f;"undefined"!=typeof window?f=window:"undefined"!=typeof global?f=global:"undefined"!=typeof self&&(f=self),f.assert=e()}}(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);throw new Error("Cannot find module '"+o+"'")}var f=n[o]={exports:{}};t[o][0].call(f.exports,function(e){var n=t[o][1][e];return s(n?n:e)},f,f.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(_dereq_,module,exports){
/**
 * power-assert.js - Power Assert in JavaScript.
 *
 * https://github.com/twada/power-assert
 *
 * Copyright (c) 2013-2014 Takuto Wada
 * Licensed under the MIT license.
 *   https://raw.github.com/twada/power-assert/master/MIT-LICENSE.txt
 */
(function (root, factory) {
    'use strict';

    // using returnExports UMD pattern
    if (typeof define === 'function' && define.amd) {
        define(['assert', 'empower', 'power-assert-formatter'], factory);
    } else if (typeof exports === 'object') {
        module.exports = factory(_dereq_('assert'), _dereq_('empower'), _dereq_('power-assert-formatter'));
    } else {
        root.assert = factory(root.assert, root.empower, root.powerAssertFormatter);
    }
}(this, function (baseAssert, empower, formatter) {
    'use strict';

    return empower(baseAssert, formatter(), {modifyMessageOnFail: true, saveContextOnFail: true});
}));

},{"assert":2,"empower":7,"power-assert-formatter":8}],2:[function(_dereq_,module,exports){
// http://wiki.commonjs.org/wiki/Unit_Testing/1.0
//
// THIS IS NOT TESTED NOR LIKELY TO WORK OUTSIDE V8!
//
// Originally from narwhal.js (http://narwhaljs.org)
// Copyright (c) 2009 Thomas Robinson <280north.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the 'Software'), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

// when used in node, this will actually load the util module we depend on
// versus loading the builtin util module as happens otherwise
// this is a bug in node module loading as far as I am concerned
var util = _dereq_('util/');

var pSlice = Array.prototype.slice;
var hasOwn = Object.prototype.hasOwnProperty;

// 1. The assert module provides functions that throw
// AssertionError's when particular conditions are not met. The
// assert module must conform to the following interface.

var assert = module.exports = ok;

// 2. The AssertionError is defined in assert.
// new assert.AssertionError({ message: message,
//                             actual: actual,
//                             expected: expected })

assert.AssertionError = function AssertionError(options) {
  this.name = 'AssertionError';
  this.actual = options.actual;
  this.expected = options.expected;
  this.operator = options.operator;
  if (options.message) {
    this.message = options.message;
    this.generatedMessage = false;
  } else {
    this.message = getMessage(this);
    this.generatedMessage = true;
  }
  var stackStartFunction = options.stackStartFunction || fail;

  if (Error.captureStackTrace) {
    Error.captureStackTrace(this, stackStartFunction);
  }
  else {
    // non v8 browsers so we can have a stacktrace
    var err = new Error();
    if (err.stack) {
      var out = err.stack;

      // try to strip useless frames
      var fn_name = stackStartFunction.name;
      var idx = out.indexOf('\n' + fn_name);
      if (idx >= 0) {
        // once we have located the function frame
        // we need to strip out everything before it (and its line)
        var next_line = out.indexOf('\n', idx + 1);
        out = out.substring(next_line + 1);
      }

      this.stack = out;
    }
  }
};

// assert.AssertionError instanceof Error
util.inherits(assert.AssertionError, Error);

function replacer(key, value) {
  if (util.isUndefined(value)) {
    return '' + value;
  }
  if (util.isNumber(value) && (isNaN(value) || !isFinite(value))) {
    return value.toString();
  }
  if (util.isFunction(value) || util.isRegExp(value)) {
    return value.toString();
  }
  return value;
}

function truncate(s, n) {
  if (util.isString(s)) {
    return s.length < n ? s : s.slice(0, n);
  } else {
    return s;
  }
}

function getMessage(self) {
  return truncate(JSON.stringify(self.actual, replacer), 128) + ' ' +
         self.operator + ' ' +
         truncate(JSON.stringify(self.expected, replacer), 128);
}

// At present only the three keys mentioned above are used and
// understood by the spec. Implementations or sub modules can pass
// other keys to the AssertionError's constructor - they will be
// ignored.

// 3. All of the following functions must throw an AssertionError
// when a corresponding condition is not met, with a message that
// may be undefined if not provided.  All assertion methods provide
// both the actual and expected values to the assertion error for
// display purposes.

function fail(actual, expected, message, operator, stackStartFunction) {
  throw new assert.AssertionError({
    message: message,
    actual: actual,
    expected: expected,
    operator: operator,
    stackStartFunction: stackStartFunction
  });
}

// EXTENSION! allows for well behaved errors defined elsewhere.
assert.fail = fail;

// 4. Pure assertion tests whether a value is truthy, as determined
// by !!guard.
// assert.ok(guard, message_opt);
// This statement is equivalent to assert.equal(true, !!guard,
// message_opt);. To test strictly for the value true, use
// assert.strictEqual(true, guard, message_opt);.

function ok(value, message) {
  if (!value) fail(value, true, message, '==', assert.ok);
}
assert.ok = ok;

// 5. The equality assertion tests shallow, coercive equality with
// ==.
// assert.equal(actual, expected, message_opt);

assert.equal = function equal(actual, expected, message) {
  if (actual != expected) fail(actual, expected, message, '==', assert.equal);
};

// 6. The non-equality assertion tests for whether two objects are not equal
// with != assert.notEqual(actual, expected, message_opt);

assert.notEqual = function notEqual(actual, expected, message) {
  if (actual == expected) {
    fail(actual, expected, message, '!=', assert.notEqual);
  }
};

// 7. The equivalence assertion tests a deep equality relation.
// assert.deepEqual(actual, expected, message_opt);

assert.deepEqual = function deepEqual(actual, expected, message) {
  if (!_deepEqual(actual, expected)) {
    fail(actual, expected, message, 'deepEqual', assert.deepEqual);
  }
};

function _deepEqual(actual, expected) {
  // 7.1. All identical values are equivalent, as determined by ===.
  if (actual === expected) {
    return true;

  } else if (util.isBuffer(actual) && util.isBuffer(expected)) {
    if (actual.length != expected.length) return false;

    for (var i = 0; i < actual.length; i++) {
      if (actual[i] !== expected[i]) return false;
    }

    return true;

  // 7.2. If the expected value is a Date object, the actual value is
  // equivalent if it is also a Date object that refers to the same time.
  } else if (util.isDate(actual) && util.isDate(expected)) {
    return actual.getTime() === expected.getTime();

  // 7.3 If the expected value is a RegExp object, the actual value is
  // equivalent if it is also a RegExp object with the same source and
  // properties (`global`, `multiline`, `lastIndex`, `ignoreCase`).
  } else if (util.isRegExp(actual) && util.isRegExp(expected)) {
    return actual.source === expected.source &&
           actual.global === expected.global &&
           actual.multiline === expected.multiline &&
           actual.lastIndex === expected.lastIndex &&
           actual.ignoreCase === expected.ignoreCase;

  // 7.4. Other pairs that do not both pass typeof value == 'object',
  // equivalence is determined by ==.
  } else if (!util.isObject(actual) && !util.isObject(expected)) {
    return actual == expected;

  // 7.5 For all other Object pairs, including Array objects, equivalence is
  // determined by having the same number of owned properties (as verified
  // with Object.prototype.hasOwnProperty.call), the same set of keys
  // (although not necessarily the same order), equivalent values for every
  // corresponding key, and an identical 'prototype' property. Note: this
  // accounts for both named and indexed properties on Arrays.
  } else {
    return objEquiv(actual, expected);
  }
}

function isArguments(object) {
  return Object.prototype.toString.call(object) == '[object Arguments]';
}

function objEquiv(a, b) {
  if (util.isNullOrUndefined(a) || util.isNullOrUndefined(b))
    return false;
  // an identical 'prototype' property.
  if (a.prototype !== b.prototype) return false;
  //~~~I've managed to break Object.keys through screwy arguments passing.
  //   Converting to array solves the problem.
  if (isArguments(a)) {
    if (!isArguments(b)) {
      return false;
    }
    a = pSlice.call(a);
    b = pSlice.call(b);
    return _deepEqual(a, b);
  }
  try {
    var ka = objectKeys(a),
        kb = objectKeys(b),
        key, i;
  } catch (e) {//happens when one is a string literal and the other isn't
    return false;
  }
  // having the same number of owned properties (keys incorporates
  // hasOwnProperty)
  if (ka.length != kb.length)
    return false;
  //the same set of keys (although not necessarily the same order),
  ka.sort();
  kb.sort();
  //~~~cheap key test
  for (i = ka.length - 1; i >= 0; i--) {
    if (ka[i] != kb[i])
      return false;
  }
  //equivalent values for every corresponding key, and
  //~~~possibly expensive deep test
  for (i = ka.length - 1; i >= 0; i--) {
    key = ka[i];
    if (!_deepEqual(a[key], b[key])) return false;
  }
  return true;
}

// 8. The non-equivalence assertion tests for any deep inequality.
// assert.notDeepEqual(actual, expected, message_opt);

assert.notDeepEqual = function notDeepEqual(actual, expected, message) {
  if (_deepEqual(actual, expected)) {
    fail(actual, expected, message, 'notDeepEqual', assert.notDeepEqual);
  }
};

// 9. The strict equality assertion tests strict equality, as determined by ===.
// assert.strictEqual(actual, expected, message_opt);

assert.strictEqual = function strictEqual(actual, expected, message) {
  if (actual !== expected) {
    fail(actual, expected, message, '===', assert.strictEqual);
  }
};

// 10. The strict non-equality assertion tests for strict inequality, as
// determined by !==.  assert.notStrictEqual(actual, expected, message_opt);

assert.notStrictEqual = function notStrictEqual(actual, expected, message) {
  if (actual === expected) {
    fail(actual, expected, message, '!==', assert.notStrictEqual);
  }
};

function expectedException(actual, expected) {
  if (!actual || !expected) {
    return false;
  }

  if (Object.prototype.toString.call(expected) == '[object RegExp]') {
    return expected.test(actual);
  } else if (actual instanceof expected) {
    return true;
  } else if (expected.call({}, actual) === true) {
    return true;
  }

  return false;
}

function _throws(shouldThrow, block, expected, message) {
  var actual;

  if (util.isString(expected)) {
    message = expected;
    expected = null;
  }

  try {
    block();
  } catch (e) {
    actual = e;
  }

  message = (expected && expected.name ? ' (' + expected.name + ').' : '.') +
            (message ? ' ' + message : '.');

  if (shouldThrow && !actual) {
    fail(actual, expected, 'Missing expected exception' + message);
  }

  if (!shouldThrow && expectedException(actual, expected)) {
    fail(actual, expected, 'Got unwanted exception' + message);
  }

  if ((shouldThrow && actual && expected &&
      !expectedException(actual, expected)) || (!shouldThrow && actual)) {
    throw actual;
  }
}

// 11. Expected to throw an error:
// assert.throws(block, Error_opt, message_opt);

assert.throws = function(block, /*optional*/error, /*optional*/message) {
  _throws.apply(this, [true].concat(pSlice.call(arguments)));
};

// EXTENSION! This is annoying to write outside this module.
assert.doesNotThrow = function(block, /*optional*/message) {
  _throws.apply(this, [false].concat(pSlice.call(arguments)));
};

assert.ifError = function(err) { if (err) {throw err;}};

var objectKeys = Object.keys || function (obj) {
  var keys = [];
  for (var key in obj) {
    if (hasOwn.call(obj, key)) keys.push(key);
  }
  return keys;
};

},{"util/":4}],3:[function(_dereq_,module,exports){
module.exports = function isBuffer(arg) {
  return arg && typeof arg === 'object'
    && typeof arg.copy === 'function'
    && typeof arg.fill === 'function'
    && typeof arg.readUInt8 === 'function';
}
},{}],4:[function(_dereq_,module,exports){
(function (process,global){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

var formatRegExp = /%[sdj%]/g;
exports.format = function(f) {
  if (!isString(f)) {
    var objects = [];
    for (var i = 0; i < arguments.length; i++) {
      objects.push(inspect(arguments[i]));
    }
    return objects.join(' ');
  }

  var i = 1;
  var args = arguments;
  var len = args.length;
  var str = String(f).replace(formatRegExp, function(x) {
    if (x === '%%') return '%';
    if (i >= len) return x;
    switch (x) {
      case '%s': return String(args[i++]);
      case '%d': return Number(args[i++]);
      case '%j':
        try {
          return JSON.stringify(args[i++]);
        } catch (_) {
          return '[Circular]';
        }
      default:
        return x;
    }
  });
  for (var x = args[i]; i < len; x = args[++i]) {
    if (isNull(x) || !isObject(x)) {
      str += ' ' + x;
    } else {
      str += ' ' + inspect(x);
    }
  }
  return str;
};


// Mark that a method should not be used.
// Returns a modified function which warns once by default.
// If --no-deprecation is set, then it is a no-op.
exports.deprecate = function(fn, msg) {
  // Allow for deprecating things in the process of starting up.
  if (isUndefined(global.process)) {
    return function() {
      return exports.deprecate(fn, msg).apply(this, arguments);
    };
  }

  if (process.noDeprecation === true) {
    return fn;
  }

  var warned = false;
  function deprecated() {
    if (!warned) {
      if (process.throwDeprecation) {
        throw new Error(msg);
      } else if (process.traceDeprecation) {
        console.trace(msg);
      } else {
        console.error(msg);
      }
      warned = true;
    }
    return fn.apply(this, arguments);
  }

  return deprecated;
};


var debugs = {};
var debugEnviron;
exports.debuglog = function(set) {
  if (isUndefined(debugEnviron))
    debugEnviron = process.env.NODE_DEBUG || '';
  set = set.toUpperCase();
  if (!debugs[set]) {
    if (new RegExp('\\b' + set + '\\b', 'i').test(debugEnviron)) {
      var pid = process.pid;
      debugs[set] = function() {
        var msg = exports.format.apply(exports, arguments);
        console.error('%s %d: %s', set, pid, msg);
      };
    } else {
      debugs[set] = function() {};
    }
  }
  return debugs[set];
};


/**
 * Echos the value of a value. Trys to print the value out
 * in the best way possible given the different types.
 *
 * @param {Object} obj The object to print out.
 * @param {Object} opts Optional options object that alters the output.
 */
/* legacy: obj, showHidden, depth, colors*/
function inspect(obj, opts) {
  // default options
  var ctx = {
    seen: [],
    stylize: stylizeNoColor
  };
  // legacy...
  if (arguments.length >= 3) ctx.depth = arguments[2];
  if (arguments.length >= 4) ctx.colors = arguments[3];
  if (isBoolean(opts)) {
    // legacy...
    ctx.showHidden = opts;
  } else if (opts) {
    // got an "options" object
    exports._extend(ctx, opts);
  }
  // set default options
  if (isUndefined(ctx.showHidden)) ctx.showHidden = false;
  if (isUndefined(ctx.depth)) ctx.depth = 2;
  if (isUndefined(ctx.colors)) ctx.colors = false;
  if (isUndefined(ctx.customInspect)) ctx.customInspect = true;
  if (ctx.colors) ctx.stylize = stylizeWithColor;
  return formatValue(ctx, obj, ctx.depth);
}
exports.inspect = inspect;


// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
  'bold' : [1, 22],
  'italic' : [3, 23],
  'underline' : [4, 24],
  'inverse' : [7, 27],
  'white' : [37, 39],
  'grey' : [90, 39],
  'black' : [30, 39],
  'blue' : [34, 39],
  'cyan' : [36, 39],
  'green' : [32, 39],
  'magenta' : [35, 39],
  'red' : [31, 39],
  'yellow' : [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
  'special': 'cyan',
  'number': 'yellow',
  'boolean': 'yellow',
  'undefined': 'grey',
  'null': 'bold',
  'string': 'green',
  'date': 'magenta',
  // "name": intentionally not styling
  'regexp': 'red'
};


function stylizeWithColor(str, styleType) {
  var style = inspect.styles[styleType];

  if (style) {
    return '\u001b[' + inspect.colors[style][0] + 'm' + str +
           '\u001b[' + inspect.colors[style][1] + 'm';
  } else {
    return str;
  }
}


function stylizeNoColor(str, styleType) {
  return str;
}


function arrayToHash(array) {
  var hash = {};

  array.forEach(function(val, idx) {
    hash[val] = true;
  });

  return hash;
}


function formatValue(ctx, value, recurseTimes) {
  // Provide a hook for user-specified inspect functions.
  // Check that value is an object with an inspect function on it
  if (ctx.customInspect &&
      value &&
      isFunction(value.inspect) &&
      // Filter out the util module, it's inspect function is special
      value.inspect !== exports.inspect &&
      // Also filter out any prototype objects using the circular check.
      !(value.constructor && value.constructor.prototype === value)) {
    var ret = value.inspect(recurseTimes, ctx);
    if (!isString(ret)) {
      ret = formatValue(ctx, ret, recurseTimes);
    }
    return ret;
  }

  // Primitive types cannot have properties
  var primitive = formatPrimitive(ctx, value);
  if (primitive) {
    return primitive;
  }

  // Look up the keys of the object.
  var keys = Object.keys(value);
  var visibleKeys = arrayToHash(keys);

  if (ctx.showHidden) {
    keys = Object.getOwnPropertyNames(value);
  }

  // IE doesn't make error fields non-enumerable
  // http://msdn.microsoft.com/en-us/library/ie/dww52sbt(v=vs.94).aspx
  if (isError(value)
      && (keys.indexOf('message') >= 0 || keys.indexOf('description') >= 0)) {
    return formatError(value);
  }

  // Some type of object without properties can be shortcutted.
  if (keys.length === 0) {
    if (isFunction(value)) {
      var name = value.name ? ': ' + value.name : '';
      return ctx.stylize('[Function' + name + ']', 'special');
    }
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    }
    if (isDate(value)) {
      return ctx.stylize(Date.prototype.toString.call(value), 'date');
    }
    if (isError(value)) {
      return formatError(value);
    }
  }

  var base = '', array = false, braces = ['{', '}'];

  // Make Array say that they are Array
  if (isArray(value)) {
    array = true;
    braces = ['[', ']'];
  }

  // Make functions say that they are functions
  if (isFunction(value)) {
    var n = value.name ? ': ' + value.name : '';
    base = ' [Function' + n + ']';
  }

  // Make RegExps say that they are RegExps
  if (isRegExp(value)) {
    base = ' ' + RegExp.prototype.toString.call(value);
  }

  // Make dates with properties first say the date
  if (isDate(value)) {
    base = ' ' + Date.prototype.toUTCString.call(value);
  }

  // Make error with message first say the error
  if (isError(value)) {
    base = ' ' + formatError(value);
  }

  if (keys.length === 0 && (!array || value.length == 0)) {
    return braces[0] + base + braces[1];
  }

  if (recurseTimes < 0) {
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    } else {
      return ctx.stylize('[Object]', 'special');
    }
  }

  ctx.seen.push(value);

  var output;
  if (array) {
    output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
  } else {
    output = keys.map(function(key) {
      return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
    });
  }

  ctx.seen.pop();

  return reduceToSingleString(output, base, braces);
}


function formatPrimitive(ctx, value) {
  if (isUndefined(value))
    return ctx.stylize('undefined', 'undefined');
  if (isString(value)) {
    var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
                                             .replace(/'/g, "\\'")
                                             .replace(/\\"/g, '"') + '\'';
    return ctx.stylize(simple, 'string');
  }
  if (isNumber(value))
    return ctx.stylize('' + value, 'number');
  if (isBoolean(value))
    return ctx.stylize('' + value, 'boolean');
  // For some reason typeof null is "object", so special case here.
  if (isNull(value))
    return ctx.stylize('null', 'null');
}


function formatError(value) {
  return '[' + Error.prototype.toString.call(value) + ']';
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  for (var i = 0, l = value.length; i < l; ++i) {
    if (hasOwnProperty(value, String(i))) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          String(i), true));
    } else {
      output.push('');
    }
  }
  keys.forEach(function(key) {
    if (!key.match(/^\d+$/)) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          key, true));
    }
  });
  return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
  var name, str, desc;
  desc = Object.getOwnPropertyDescriptor(value, key) || { value: value[key] };
  if (desc.get) {
    if (desc.set) {
      str = ctx.stylize('[Getter/Setter]', 'special');
    } else {
      str = ctx.stylize('[Getter]', 'special');
    }
  } else {
    if (desc.set) {
      str = ctx.stylize('[Setter]', 'special');
    }
  }
  if (!hasOwnProperty(visibleKeys, key)) {
    name = '[' + key + ']';
  }
  if (!str) {
    if (ctx.seen.indexOf(desc.value) < 0) {
      if (isNull(recurseTimes)) {
        str = formatValue(ctx, desc.value, null);
      } else {
        str = formatValue(ctx, desc.value, recurseTimes - 1);
      }
      if (str.indexOf('\n') > -1) {
        if (array) {
          str = str.split('\n').map(function(line) {
            return '  ' + line;
          }).join('\n').substr(2);
        } else {
          str = '\n' + str.split('\n').map(function(line) {
            return '   ' + line;
          }).join('\n');
        }
      }
    } else {
      str = ctx.stylize('[Circular]', 'special');
    }
  }
  if (isUndefined(name)) {
    if (array && key.match(/^\d+$/)) {
      return str;
    }
    name = JSON.stringify('' + key);
    if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
      name = name.substr(1, name.length - 2);
      name = ctx.stylize(name, 'name');
    } else {
      name = name.replace(/'/g, "\\'")
                 .replace(/\\"/g, '"')
                 .replace(/(^"|"$)/g, "'");
      name = ctx.stylize(name, 'string');
    }
  }

  return name + ': ' + str;
}


function reduceToSingleString(output, base, braces) {
  var numLinesEst = 0;
  var length = output.reduce(function(prev, cur) {
    numLinesEst++;
    if (cur.indexOf('\n') >= 0) numLinesEst++;
    return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
  }, 0);

  if (length > 60) {
    return braces[0] +
           (base === '' ? '' : base + '\n ') +
           ' ' +
           output.join(',\n  ') +
           ' ' +
           braces[1];
  }

  return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}


// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
function isArray(ar) {
  return Array.isArray(ar);
}
exports.isArray = isArray;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
  return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
  return arg == null;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
  return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
  return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
  return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
  return arg === void 0;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
  return isObject(re) && objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}
exports.isObject = isObject;

function isDate(d) {
  return isObject(d) && objectToString(d) === '[object Date]';
}
exports.isDate = isDate;

function isError(e) {
  return isObject(e) &&
      (objectToString(e) === '[object Error]' || e instanceof Error);
}
exports.isError = isError;

function isFunction(arg) {
  return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
  return arg === null ||
         typeof arg === 'boolean' ||
         typeof arg === 'number' ||
         typeof arg === 'string' ||
         typeof arg === 'symbol' ||  // ES6 symbol
         typeof arg === 'undefined';
}
exports.isPrimitive = isPrimitive;

exports.isBuffer = _dereq_('./support/isBuffer');

function objectToString(o) {
  return Object.prototype.toString.call(o);
}


function pad(n) {
  return n < 10 ? '0' + n.toString(10) : n.toString(10);
}


var months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
              'Oct', 'Nov', 'Dec'];

// 26 Feb 16:19:34
function timestamp() {
  var d = new Date();
  var time = [pad(d.getHours()),
              pad(d.getMinutes()),
              pad(d.getSeconds())].join(':');
  return [d.getDate(), months[d.getMonth()], time].join(' ');
}


// log is just a thin wrapper to console.log that prepends a timestamp
exports.log = function() {
  console.log('%s - %s', timestamp(), exports.format.apply(exports, arguments));
};


/**
 * Inherit the prototype methods from one constructor into another.
 *
 * The Function.prototype.inherits from lang.js rewritten as a standalone
 * function (not on Function.prototype). NOTE: If this file is to be loaded
 * during bootstrapping this function needs to be rewritten using some native
 * functions as prototype setup using normal JavaScript does not work as
 * expected during bootstrapping (see mirror.js in r114903).
 *
 * @param {function} ctor Constructor function which needs to inherit the
 *     prototype.
 * @param {function} superCtor Constructor function to inherit prototype from.
 */
exports.inherits = _dereq_('inherits');

exports._extend = function(origin, add) {
  // Don't do anything if add isn't an object
  if (!add || !isObject(add)) return origin;

  var keys = Object.keys(add);
  var i = keys.length;
  while (i--) {
    origin[keys[i]] = add[keys[i]];
  }
  return origin;
};

function hasOwnProperty(obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

}).call(this,_dereq_("FWaASH"),typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./support/isBuffer":3,"FWaASH":6,"inherits":5}],5:[function(_dereq_,module,exports){
if (typeof Object.create === 'function') {
  // implementation from standard node.js 'util' module
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    ctor.prototype = Object.create(superCtor.prototype, {
      constructor: {
        value: ctor,
        enumerable: false,
        writable: true,
        configurable: true
      }
    });
  };
} else {
  // old school shim for old browsers
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    var TempCtor = function () {}
    TempCtor.prototype = superCtor.prototype
    ctor.prototype = new TempCtor()
    ctor.prototype.constructor = ctor
  }
}

},{}],6:[function(_dereq_,module,exports){
// shim for using process in browser

var process = module.exports = {};

process.nextTick = (function () {
    var canSetImmediate = typeof window !== 'undefined'
    && window.setImmediate;
    var canPost = typeof window !== 'undefined'
    && window.postMessage && window.addEventListener
    ;

    if (canSetImmediate) {
        return function (f) { return window.setImmediate(f) };
    }

    if (canPost) {
        var queue = [];
        window.addEventListener('message', function (ev) {
            var source = ev.source;
            if ((source === window || source === null) && ev.data === 'process-tick') {
                ev.stopPropagation();
                if (queue.length > 0) {
                    var fn = queue.shift();
                    fn();
                }
            }
        }, true);

        return function nextTick(fn) {
            queue.push(fn);
            window.postMessage('process-tick', '*');
        };
    }

    return function nextTick(fn) {
        setTimeout(fn, 0);
    };
})();

process.title = 'browser';
process.browser = true;
process.env = {};
process.argv = [];

function noop() {}

process.on = noop;
process.addListener = noop;
process.once = noop;
process.off = noop;
process.removeListener = noop;
process.removeAllListeners = noop;
process.emit = noop;

process.binding = function (name) {
    throw new Error('process.binding is not supported');
}

// TODO(shtylman)
process.cwd = function () { return '/' };
process.chdir = function (dir) {
    throw new Error('process.chdir is not supported');
};

},{}],7:[function(_dereq_,module,exports){
/**
 * empower.js - Power Assert feature enhancer for assert function/object.
 *
 * https://github.com/twada/empower
 *
 * Copyright (c) 2013-2014 Takuto Wada
 * Licensed under the MIT license.
 *   https://raw.github.com/twada/empower/master/MIT-LICENSE.txt
 *
 * A part of extend function is:
 *   Copyright 2012 jQuery Foundation and other contributors
 *   Released under the MIT license.
 *   http://jquery.org/license
 */
(function (root, factory) {
    'use strict';

    // using returnExports UMD pattern
    if (typeof define === 'function' && define.amd) {
        define(factory);
    } else if (typeof exports === 'object') {
        module.exports = factory();
    } else {
        root.empower = factory();
    }
}(this, function () {
    'use strict';

    var isPhantom = typeof window !== 'undefined' && typeof window.callPhantom === 'function';

    function defaultOptions () {
        return {
            destructive: false,
            modifyMessageOnFail: false,
            saveContextOnFail: false,
            targetMethods: {
                oneArg: [
                    'ok'
                ],
                twoArgs: [
                    'equal',
                    'notEqual',
                    'strictEqual',
                    'notStrictEqual',
                    'deepEqual',
                    'notDeepEqual'
                ]
            }
        };
    }


    /**
     * Enhance Power Assert feature to assert function/object.
     * @param assert target assert function or object to enhance
     * @param formatter power assert format function
     * @param options enhancement options
     * @return enhanced assert function/object
     */
    function empower (assert, formatter, options) {
        var typeOfAssert = (typeof assert),
            config;
        if ((typeOfAssert !== 'object' && typeOfAssert !== 'function') || assert === null) {
            throw new TypeError('empower argument should be a function or object.');
        }
        if (isEmpowered(assert)) {
            return assert;
        }
        config = extend(defaultOptions(), (options || {}));
        switch (typeOfAssert) {
        case 'function':
            return empowerAssertFunction(assert, formatter, config);
        case 'object':
            return empowerAssertObject(assert, formatter, config);
        default:
            throw new Error('Cannot be here');
        }
    }


    function isEmpowered (assertObjectOrFunction) {
        return (typeof assertObjectOrFunction._capt === 'function') && (typeof assertObjectOrFunction._expr === 'function');
    }


    function empowerAssertObject (assertObject, formatter, config) {
        var enhancement = enhance(assertObject, formatter, config),
            target = config.destructive ? assertObject : Object.create(assertObject);
        return extend(target, enhancement);
    }


    function empowerAssertFunction (assertFunction, formatter, config) {
        if (config.destructive) {
            throw new Error('cannot use destructive:true to function.');
        }
        var enhancement = enhance(assertFunction, formatter, config),
            powerAssert = function powerAssert (context, message) {
                enhancement(context, message);
            };
        extend(powerAssert, assertFunction);
        return extend(powerAssert, enhancement);
    }


    function enhance (target, formatter, config) {
        var eagerEvaluation = !(config.modifyMessageOnFail || config.saveContextOnFail),
            doPowerAssert = function (baseAssert, args, message, context) {
                var f;
                if (eagerEvaluation) {
                    args.push(buildPowerAssertText(message, context));
                    return baseAssert.apply(target, args);
                }
                try {
                    args.push(message);
                    return baseAssert.apply(target, args);
                } catch (e) {
                    if (e.name !== 'AssertionError') {
                        throw e;
                    }
                    if (typeof target.AssertionError !== 'function') {
                        throw e;
                    }
                    if (isPhantom) {
                        f = new target.AssertionError({
                            actual: e.actual,
                            expected: e.expected,
                            operator: e.operator,
                            message: e.message
                        });
                    } else {
                        f = e;
                    }
                    if (config.modifyMessageOnFail) {
                        f.message = buildPowerAssertText(message, context);
                        if (typeof e.generatedMessage !== 'undefined') {
                            f.generatedMessage = false;
                        }
                    }
                    if (config.saveContextOnFail) {
                        f.powerAssertContext = context;
                    }
                    throw f;
                }
            },
            enhancement = (typeof target === 'function') ? decorateOneArg(target, target, doPowerAssert) : {},
            events = [];

        function buildPowerAssertText (message, context) {
            var powerAssertText = formatter(context);
            return message ? message + ' ' + powerAssertText : powerAssertText;
        }

        function _capt (value, espath) {
            events.push({value: value, espath: espath});
            return value;
        }

        function _expr (value, args) {
            var captured = events;
            events = [];
            return { powerAssertContext: {value: value, events: captured}, source: {content: args.content, filepath: args.filepath, line: args.line} };
        }

        config.targetMethods.oneArg.forEach(function (methodName) {
            if (typeof target[methodName] === 'function') {
                enhancement[methodName] = decorateOneArg(target, target[methodName], doPowerAssert);
            }
        });
        config.targetMethods.twoArgs.forEach(function (methodName) {
            if (typeof target[methodName] === 'function') {
                enhancement[methodName] = decorateTwoArgs(target, target[methodName], doPowerAssert);
            }
        });

        enhancement._capt = _capt;
        enhancement._expr = _expr;
        return enhancement;
    }


    function isEspoweredValue (value) {
        return (typeof value === 'object') && (value !== null) && (typeof value.powerAssertContext !== 'undefined');
    }


    function decorateOneArg (target, baseAssert, doPowerAssert) {
        return function (arg1, message) {
            var context, val1;
            if (! isEspoweredValue(arg1)) {
                return baseAssert.apply(target, [arg1, message]);
            }
            val1 = arg1.powerAssertContext.value;
            context = {
                source: arg1.source,
                args: []
            };
            context.args.push({
                value: val1,
                events: arg1.powerAssertContext.events
            });
            return doPowerAssert(baseAssert, [val1], message, context);
        };
    }


    function decorateTwoArgs (target, baseAssert, doPowerAssert) {
        return function (arg1, arg2, message) {
            var context, val1, val2;
            if (!(isEspoweredValue(arg1) || isEspoweredValue(arg2))) {
                return baseAssert.apply(target, [arg1, arg2, message]);
            }

            if (isEspoweredValue(arg1)) {
                context = {
                    source: arg1.source,
                    args: []
                };
                context.args.push({
                    value: arg1.powerAssertContext.value,
                    events: arg1.powerAssertContext.events
                });
                val1 = arg1.powerAssertContext.value;
            } else {
                val1 = arg1;
            }

            if (isEspoweredValue(arg2)) {
                if (!isEspoweredValue(arg1)) {
                    context = {
                        source: arg2.source,
                        args: []
                    };
                }
                context.args.push({
                    value: arg2.powerAssertContext.value,
                    events: arg2.powerAssertContext.events
                });
                val2 = arg2.powerAssertContext.value;
            } else {
                val2 = arg2;
            }

            return doPowerAssert(baseAssert, [val1, val2], message, context);
        };
    }


    // borrowed from qunit.js
    function extend (a, b) {
        var prop;
        for (prop in b) {
            if (b.hasOwnProperty(prop)) {
                if (typeof b[prop] === 'undefined') {
                    delete a[prop];
                } else {
                    a[prop] = b[prop];
                }
            }
        }
        return a;
    }


    // using returnExports UMD pattern with substack pattern
    empower.defaultOptions = defaultOptions;
    return empower;
}));

},{}],8:[function(_dereq_,module,exports){
/**
 * power-assert-formatter.js - Power Assert output formatter
 *
 * https://github.com/twada/power-assert-formatter
 *
 * Copyright (c) 2013-2014 Takuto Wada
 * Licensed under the MIT license.
 *   https://raw.github.com/twada/power-assert-formatter/master/MIT-LICENSE.txt
 *
 * A part of extend function is:
 *   Copyright 2012 jQuery Foundation and other contributors
 *   Released under the MIT license.
 *   http://jquery.org/license
 */
(function (root, factory) {
    'use strict';
    /*jshint camelcase: false */

    // using returnExports UMD pattern
    if (typeof define === 'function' && define.amd) {
        define(['estraverse', 'esprima', 'diff_match_patch'], factory);
    } else if (typeof exports === 'object') {
        module.exports = factory(_dereq_('estraverse'), _dereq_('esprima'), _dereq_('googlediff'));
    } else {
        root.powerAssertFormatter = factory(root.estraverse, root.esprima, root.diff_match_patch);
    }
}(this, function (estraverse, esprima, DiffMatchPatch) {
    'use strict';

    var syntax, dmp;

    function defaultOptions () {
        return {
            lineDiffThreshold: 5,
            stringifyDepth: 2,
            lineSeparator: '\n'
        };
    }


    function PowerAssertContextRenderer (config) {
        this.config = config;
        this.stringify = config.stringify;
        this.compare = config.compare;
        this.widthOf = config.widthOf;
        this.initialVertivalBarLength = 1;
    }

    PowerAssertContextRenderer.prototype.init = function (context) {
        this.context = context;
        this.assertionLine = context.source.content;
        this.filepath = context.source.filepath;
        this.lineNumber = context.source.line;
        this.initializeRows();
    };

    PowerAssertContextRenderer.prototype.initializeRows = function () {
        this.rows = [];
        for (var i = 0; i <= this.initialVertivalBarLength; i += 1) {
            this.addOneMoreRow();
        }
    };

    PowerAssertContextRenderer.prototype.newRowFor = function (assertionLine) {
        return createRow(this.widthOf(assertionLine), ' ');
    };

    PowerAssertContextRenderer.prototype.addOneMoreRow = function () {
        this.rows.push(this.newRowFor(this.assertionLine));
    };

    PowerAssertContextRenderer.prototype.lastRow = function () {
        return this.rows[this.rows.length - 1];
    };

    PowerAssertContextRenderer.prototype.renderVerticalBarAt = function (columnIndex) {
        var i, lastRowIndex = this.rows.length - 1;
        for (i = 0; i < lastRowIndex; i += 1) {
            this.rows[i].splice(columnIndex, 1, '|');
        }
    };

    PowerAssertContextRenderer.prototype.renderValueAt = function (columnIndex, dumpedValue) {
        var i, width = this.widthOf(dumpedValue);
        for (i = 0; i < width; i += 1) {
            this.lastRow().splice(columnIndex + i, 1, dumpedValue.charAt(i));
        }
    };

    PowerAssertContextRenderer.prototype.isOverlapped = function (prevCapturing, nextCaputuring, dumpedValue) {
        return (typeof prevCapturing !== 'undefined') && this.startColumnFor(prevCapturing) <= (this.startColumnFor(nextCaputuring) + this.widthOf(dumpedValue));
    };

    PowerAssertContextRenderer.prototype.constructRows = function (capturedEvents) {
        var that = this,
            prevCaptured;
        capturedEvents.forEach(function (captured) {
            var dumpedValue = that.stringify(captured.value);
            if (that.isOverlapped(prevCaptured, captured, dumpedValue)) {
                that.addOneMoreRow();
            }
            that.renderVerticalBarAt(that.startColumnFor(captured));
            that.renderValueAt(that.startColumnFor(captured), dumpedValue);
            prevCaptured = captured;
        });
    };

    PowerAssertContextRenderer.prototype.startColumnFor = function (captured) {
        return this.widthOf(this.assertionLine.slice(0, captured.loc.start.column));
    };

    PowerAssertContextRenderer.prototype.renderLines = function () {
        var that = this,
            lines = [],
            events = [],
            pairs = [];

        if (this.filepath) {
            lines.push('# ' + [this.filepath, this.lineNumber].join(':'));
        } else {
            lines.push('# at line: ' + this.lineNumber);
        }
        lines.push('');
        lines.push(this.assertionLine);

        traverseContext(this.context, events, pairs);

        events.sort(rightToLeft);
        this.constructRows(events);
        this.rows.forEach(function (columns) {
            lines.push(columns.join(''));
        });

        pairs.forEach(function (pair) {
            that.compare(pair, lines);
        });

        lines.push('');
        return lines;
    };


    function EsNode (path, currentNode, parentNode, espathToValue, jsCode, jsAST) {
        if (path) {
            this.espath = path.join('/');
            this.parentEspath = path.slice(0, path.length - 1).join('/');
            this.currentProp = path[path.length - 1];
        } else {
            this.espath = '';
            this.parentEspath = '';
            this.currentProp = null;
        }
        this.currentNode = currentNode;
        this.parentNode = parentNode;
        this.parentEsNode = null;
        this.espathToValue = espathToValue;
        this.jsCode = jsCode;
        this.jsAST = jsAST;
    }
    EsNode.prototype.setParentEsNode = function (parentEsNode) {
        this.parentEsNode = parentEsNode;
    };
    EsNode.prototype.getParentEsNode = function () {
        return this.parentEsNode;
    };
    EsNode.prototype.code = function () {
        return this.jsCode.slice(this.currentNode.loc.start.column, this.currentNode.loc.end.column);
    };
    EsNode.prototype.value = function () {
        if (this.currentNode.type === syntax.Literal) {
            return this.currentNode.value;
        }
        return this.espathToValue[this.espath];
    };
    EsNode.prototype.isCaptured = function () {
        return this.espathToValue.hasOwnProperty(this.espath);
    };
    EsNode.prototype.location = function () {
        return locationOf(this.currentNode, this.jsAST.tokens);
    };


    function traverseContext (context, events, pairs) {
        context.args.forEach(function (arg) {
            var espathToPair = {};
            onEachEsNode(arg, context.source.content, function (esNode) {
                var pair;
                if (!esNode.isCaptured()) {
                    if (isTargetBinaryExpression(esNode.getParentEsNode()) && esNode.currentNode.type === syntax.Literal) {
                        espathToPair[esNode.parentEspath][esNode.currentProp] = {code: esNode.code(), value: esNode.value()};
                    }
                    return;
                }
                events.push({value: esNode.value(), espath: esNode.espath, loc: esNode.location()});
                if (isTargetBinaryExpression(esNode.getParentEsNode())) {
                    espathToPair[esNode.parentEspath][esNode.currentProp] = {code: esNode.code(), value: esNode.value()};
                }
                if (isTargetBinaryExpression(esNode)) {
                    pair = {
                        operator: esNode.currentNode.operator,
                        value: esNode.value()
                    };
                    espathToPair[esNode.espath] = pair;
                }
            });
            Object.keys(espathToPair).forEach(function (espath) {
                var pair = espathToPair[espath];
                if (pair.left && pair.right) {
                    pairs.push(pair);
                }
            });
        });
    }


    function isTargetBinaryExpression (esNode) {
        return esNode &&
            esNode.currentNode.type === syntax.BinaryExpression &&
            (esNode.currentNode.operator === '===' || esNode.currentNode.operator === '==') &&
            esNode.isCaptured() &&
            !(esNode.value());
    }


    function onEachEsNode(arg, jsCode, callback) {
        var jsAST = esprima.parse(jsCode, {tolerant: true, loc: true, tokens: true, raw: true}),
            espathToValue = arg.events.reduce(function (accum, ev) {
                accum[ev.espath] = ev.value;
                return accum;
            }, {}),
            nodeStack = [];
        estraverse.traverse(extractExpressionFrom(jsAST), {
            enter: function (currentNode, parentNode) {
                var esNode = new EsNode(this.path(), currentNode, parentNode, espathToValue, jsCode, jsAST);
                if (1 < nodeStack.length) {
                    esNode.setParentEsNode(nodeStack[nodeStack.length - 1]);
                }
                nodeStack.push(esNode);
                callback(esNode);
            },
            leave: function (currentNode, parentNode) {
                nodeStack.pop();
            }
        });
    }


    function extractExpressionFrom (tree) {
        var expressionStatement = tree.body[0],
            expression = expressionStatement.expression;
        return expression;
    }


    function locationOf(currentNode, tokens) {
        switch(currentNode.type) {
        case syntax.MemberExpression:
            return propertyLocationOf(currentNode, tokens);
        case syntax.CallExpression:
            if (currentNode.callee.type === syntax.MemberExpression) {
                return propertyLocationOf(currentNode.callee, tokens);
            }
            break;
        case syntax.BinaryExpression:
        case syntax.LogicalExpression:
        case syntax.AssignmentExpression:
            return infixOperatorLocationOf(currentNode, tokens);
        default:
            break;
        }
        return currentNode.loc;
    }


    function propertyLocationOf(memberExpression, tokens) {
        var prop = memberExpression.property,
            token;
        if (!memberExpression.computed) {
            return prop.loc;
        }
        token = findLeftBracketTokenOf(memberExpression, tokens);
        return token ? token.loc : prop.loc;
    }


    // calculate location of infix operator for BinaryExpression, AssignmentExpression and LogicalExpression.
    function infixOperatorLocationOf (expression, tokens) {
        var token = findOperatorTokenOf(expression, tokens);
        return token ? token.loc : expression.left.loc;
    }


    function findLeftBracketTokenOf(expression, tokens) {
        var fromLine = expression.loc.start.line,
            toLine = expression.property.loc.start.line,
            fromColumn = expression.property.loc.start.column;
        return searchToken(tokens, fromLine, toLine, function (token, index) {
            var prevToken;
            if (token.loc.start.column === fromColumn) {
                prevToken = tokens[index - 1];
                if (prevToken.type === 'Punctuator' && prevToken.value === '[') {
                    return prevToken;
                }
            }
            return undefined;
        });
    }


    function findOperatorTokenOf(expression, tokens) {
        var fromLine = expression.left.loc.end.line,
            toLine = expression.right.loc.start.line,
            fromColumn = expression.left.loc.end.column,
            toColumn = expression.right.loc.start.column;
        return searchToken(tokens, fromLine, toLine, function (token, index) {
            if (fromColumn < token.loc.start.column &&
                token.loc.end.column < toColumn &&
                token.type === 'Punctuator' &&
                token.value === expression.operator) {
                return token;
            }
            return undefined;
        });
    }


    function searchToken(tokens, fromLine, toLine, predicate) {
        var i, token, found;
        for(i = 0; i < tokens.length; i += 1) {
            token = tokens[i];
            if (token.loc.start.line < fromLine) {
                continue;
            }
            if (toLine < token.loc.end.line) {
                break;
            }
            found = predicate(token, i);
            if (found) {
                return found;
            }
        }
        return undefined;
    }


    function createRow (numCols, initial) {
        var row = [], i;
        for(i = 0; i < numCols; i += 1) {
            row[i] = initial;
        }
        return row;
    }


    function rightToLeft (a, b) {
        return b.loc.start.column - a.loc.start.column;
    }


    function multibyteStringWidthOf (str) {
        var i, c, width = 0;
        for(i = 0; i < str.length; i+=1){
            c = str.charCodeAt(i);
            if ((0x0 <= c && c < 0x81) || (c === 0xf8f0) || (0xff61 <= c && c < 0xffa0) || (0xf8f1 <= c && c < 0xf8f4)) {
                width += 1;
            } else {
                width += 2;
            }
        }
        return width;
    }


    function constructorNameOf (obj) {
        var ctor = obj.constructor,
            cname = '';
        if (typeof(ctor) === 'function') {
            cname = ctor.name ? ctor.name : Object.prototype.toString.call(obj).slice(8, -1);
        }
        return cname ? cname : 'Object';
    }


    function typeNameOf (val) {
        var type = typeof(val);
        if (val === null) {
            return 'null';
        }
        if (typeof val === 'undefined') {
            return 'undefined';
        }
        if (type === 'object') {
            if (Array.isArray(val)) {
                return 'Array';
            }
            return constructorNameOf(val);
        }
        return type;
    }


    function isComparedByValue (obj) {
        if (obj === null) {
            return true;
        }
        switch(typeof obj) {
        case 'string':
        case 'number':
        case 'boolean':
        case 'undefined':
            return true;
        }
        return false;
    }


    // borrowed from qunit.js
    function extend (a, b) {
        var prop;
        for (prop in b) {
            if (b.hasOwnProperty(prop)) {
                if (typeof b[prop] === 'undefined') {
                    delete a[prop];
                } else {
                    a[prop] = b[prop];
                }
            }
        }
        return a;
    }


    function defaultStringifier (config) {
        var globalConstructors = [
            Boolean,
            Date,
            Number,
            RegExp,
            String
        ];

        function stringify(obj, depth) {
            if (typeof depth !== 'number') {
                depth = config.stringifyDepth;
            }
            return stringifyAny(obj, depth);
        }

        function stringifyAny(obj, depth) {
            switch(typeof obj) {
            case 'string':
            case 'boolean':
                return JSON.stringify(obj);
            case 'number':
                return stringifyNumber(obj);
            case 'function':
                return '#function#';
            case 'undefined':
                return 'undefined';
            case 'object':
                if (obj === null) {
                    return 'null';
                } else if (Array.isArray(obj)) {
                    return stringifyArray(obj, depth);
                } else {
                    return stringifyObject(obj, depth);
                }
                break;
            default:
                break;
            }
        }

        function stringifyNumber(num) {
            if (isNaN(num)) {
                return 'NaN';
            }
            if (!isFinite(num)) {
                return num === Infinity ? 'Infinity' : '-Infinity';
            }
            return JSON.stringify(num);
        }

        function stringifyArray(ary, depth) {
            depth -= 1;
            if (depth === 0) {
                return '#Array#';
            }
            return '[' + ary.map(function (elem, idx) {
                return stringifyAny(elem, depth);
            }).join(',') + ']';
        }

        function stringifyObject(obj, depth) {
            var pairs, cname;
            depth -= 1;
            if (obj instanceof RegExp) {
                return obj.toString();
            }
            cname = constructorNameOf(obj);
            if (globalConstructors.some(function (ctor) { return obj instanceof ctor; })) {
                return 'new ' + cname + '(' + JSON.stringify(obj) + ')';
            }
            if (depth === 0) {
                return '#' + cname + '#';
            }
            pairs = [];
            Object.keys(obj).forEach(function (key) {
                var val = stringifyAny(obj[key], depth);
                if (!/^[A-Za-z_]+$/.test(key)) {
                    key = JSON.stringify(key);
                }
                pairs.push(key + ':' + val);
            });
            return cname + '{' + pairs.join(',') + '}';
        }

        return stringify;
    }


    function defaultComparator(config) {
        function compare(pair, lines) {
            if (isStringDiffTarget(pair)) {
                showStringDiff(pair, lines);
            } else {
                showExpectedAndActual(pair, lines);
            }
        }

        function isStringDiffTarget(pair) {
            return typeof pair.left.value === 'string' && typeof pair.right.value === 'string';
        }

        function showExpectedAndActual (pair, lines) {
            lines.push('');
            lines.push('[' + typeNameOf(pair.right.value) + '] ' + pair.right.code);
            lines.push('=> ' + config.stringify(pair.right.value));
            lines.push('[' + typeNameOf(pair.left.value)  + '] ' + pair.left.code);
            lines.push('=> ' + config.stringify(pair.left.value));
        }

        function showStringDiff (pair, lines) {
            var patch;
            if (shouldUseLineLevelDiff(pair.right.value)) {
                patch = udiffLines(pair.right.value, pair.left.value);
            } else {
                patch = udiffChars(pair.right.value, pair.left.value);
            }
            lines.push('');
            lines.push('--- [string] ' + pair.right.code);
            lines.push('+++ [string] ' + pair.left.code);
            lines.push(decodeURIComponent(patch));
        }

        function shouldUseLineLevelDiff (text) {
            return config.lineDiffThreshold < text.split(/\r\n|\r|\n/).length;
        }

        function udiffLines(text1, text2) {
            /*jshint camelcase: false */
            var a = dmp.diff_linesToChars_(text1, text2),
                diffs = dmp.diff_main(a.chars1, a.chars2, false);
            dmp.diff_charsToLines_(diffs, a.lineArray);
            dmp.diff_cleanupSemantic(diffs);
            return dmp.patch_toText(dmp.patch_make(text1, diffs));
        }

        function udiffChars (text1, text2) {
            /*jshint camelcase: false */
            var diffs = dmp.diff_main(text1, text2, false);
            dmp.diff_cleanupSemantic(diffs);
            return dmp.patch_toText(dmp.patch_make(text1, diffs));
        }

        return compare;
    }


    function create (options) {
        var config = extend(defaultOptions(), (options || {}));
        if (typeof config.widthOf !== 'function') {
            config.widthOf = multibyteStringWidthOf;
        }
        if (typeof config.stringify !== 'function') {
            config.stringify = defaultStringifier(config);
        }
        if (typeof config.compare !== 'function') {
            config.compare = defaultComparator(config);
        }
        return function (context) {
            if (!DiffMatchPatch) {
                throw new Error('power-assert requires google\'s `diff_match_patch` library since 0.7.0. Please check your dependencies.');
            }
            if (!estraverse) {
                throw new Error('power-assert requires `estraverse` library since 0.6.0. Please check your dependencies.');
            } else {
            }
            if (!esprima) {
                throw new Error('power-assert requires `esprima` library since 0.7.0. Please check your dependencies.');
            }
            dmp = new DiffMatchPatch();
            syntax = estraverse.Syntax;

            var renderer = new PowerAssertContextRenderer(config);
            renderer.init(context);
            return renderer.renderLines().join(config.lineSeparator);
        };
    }

    create.PowerAssertContextRenderer = PowerAssertContextRenderer;
    create.constructorNameOf = constructorNameOf;
    create.typeNameOf = typeNameOf;
    create.isComparedByValue = isComparedByValue;
    return create;
}));

},{"esprima":9,"estraverse":10,"googlediff":11}],9:[function(_dereq_,module,exports){
/*
  Copyright (C) 2013 Ariya Hidayat <ariya.hidayat@gmail.com>
  Copyright (C) 2013 Thaddee Tyl <thaddee.tyl@gmail.com>
  Copyright (C) 2013 Mathias Bynens <mathias@qiwi.be>
  Copyright (C) 2012 Ariya Hidayat <ariya.hidayat@gmail.com>
  Copyright (C) 2012 Mathias Bynens <mathias@qiwi.be>
  Copyright (C) 2012 Joost-Wim Boekesteijn <joost-wim@boekesteijn.nl>
  Copyright (C) 2012 Kris Kowal <kris.kowal@cixar.com>
  Copyright (C) 2012 Yusuke Suzuki <utatane.tea@gmail.com>
  Copyright (C) 2012 Arpad Borsos <arpad.borsos@googlemail.com>
  Copyright (C) 2011 Ariya Hidayat <ariya.hidayat@gmail.com>

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

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

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

/*jslint bitwise:true plusplus:true */
/*global esprima:true, define:true, exports:true, window: true,
throwErrorTolerant: true,
throwError: true, generateStatement: true, peek: true,
parseAssignmentExpression: true, parseBlock: true, parseExpression: true,
parseFunctionDeclaration: true, parseFunctionExpression: true,
parseFunctionSourceElements: true, parseVariableIdentifier: true,
parseLeftHandSideExpression: true,
parseUnaryExpression: true,
parseStatement: true, parseSourceElement: true */

(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,
        PropertyKind,
        Messages,
        Regex,
        SyntaxTreeDelegate,
        source,
        strict,
        index,
        lineNumber,
        lineStart,
        length,
        delegate,
        lookahead,
        state,
        extra;

    Token = {
        BooleanLiteral: 1,
        EOF: 2,
        Identifier: 3,
        Keyword: 4,
        NullLiteral: 5,
        NumericLiteral: 6,
        Punctuator: 7,
        StringLiteral: 8,
        RegularExpression: 9
    };

    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';

    // 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',
        ArrayExpression: 'ArrayExpression',
        BlockStatement: 'BlockStatement',
        BinaryExpression: 'BinaryExpression',
        BreakStatement: 'BreakStatement',
        CallExpression: 'CallExpression',
        CatchClause: 'CatchClause',
        ConditionalExpression: 'ConditionalExpression',
        ContinueStatement: 'ContinueStatement',
        DoWhileStatement: 'DoWhileStatement',
        DebuggerStatement: 'DebuggerStatement',
        EmptyStatement: 'EmptyStatement',
        ExpressionStatement: 'ExpressionStatement',
        ForStatement: 'ForStatement',
        ForInStatement: 'ForInStatement',
        FunctionDeclaration: 'FunctionDeclaration',
        FunctionExpression: 'FunctionExpression',
        Identifier: 'Identifier',
        IfStatement: 'IfStatement',
        Literal: 'Literal',
        LabeledStatement: 'LabeledStatement',
        LogicalExpression: 'LogicalExpression',
        MemberExpression: 'MemberExpression',
        NewExpression: 'NewExpression',
        ObjectExpression: 'ObjectExpression',
        Program: 'Program',
        Property: 'Property',
        ReturnStatement: 'ReturnStatement',
        SequenceExpression: 'SequenceExpression',
        SwitchStatement: 'SwitchStatement',
        SwitchCase: 'SwitchCase',
        ThisExpression: 'ThisExpression',
        ThrowStatement: 'ThrowStatement',
        TryStatement: 'TryStatement',
        UnaryExpression: 'UnaryExpression',
        UpdateExpression: 'UpdateExpression',
        VariableDeclaration: 'VariableDeclaration',
        VariableDeclarator: 'VariableDeclarator',
        WhileStatement: 'WhileStatement',
        WithStatement: 'WithStatement'
    };

    PropertyKind = {
        Data: 1,
        Get: 2,
        Set: 4
    };

    // 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',
        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',
        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.',
        StrictDuplicateProperty:  'Duplicate data property in object literal not allowed in strict mode',
        AccessorDataProperty:  'Object literal may not have data and accessor property with the same name',
        AccessorGetSet:  'Object literal may not have multiple get/set accessors with the same name',
        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'
    };

    // See also tools/generate-unicode-regex.py.
    Regex = {
        NonAsciiIdentifierStart: new RegExp('[\xAA\xB5\xBA\xC0-\xD6\xD8-\xF6\xF8-\u02C1\u02C6-\u02D1\u02E0-\u02E4\u02EC\u02EE\u0370-\u0374\u0376\u0377\u037A-\u037D\u0386\u0388-\u038A\u038C\u038E-\u03A1\u03A3-\u03F5\u03F7-\u0481\u048A-\u0527\u0531-\u0556\u0559\u0561-\u0587\u05D0-\u05EA\u05F0-\u05F2\u0620-\u064A\u066E\u066F\u0671-\u06D3\u06D5\u06E5\u06E6\u06EE\u06EF\u06FA-\u06FC\u06FF\u0710\u0712-\u072F\u074D-\u07A5\u07B1\u07CA-\u07EA\u07F4\u07F5\u07FA\u0800-\u0815\u081A\u0824\u0828\u0840-\u0858\u08A0\u08A2-\u08AC\u0904-\u0939\u093D\u0950\u0958-\u0961\u0971-\u0977\u0979-\u097F\u0985-\u098C\u098F\u0990\u0993-\u09A8\u09AA-\u09B0\u09B2\u09B6-\u09B9\u09BD\u09CE\u09DC\u09DD\u09DF-\u09E1\u09F0\u09F1\u0A05-\u0A0A\u0A0F\u0A10\u0A13-\u0A28\u0A2A-\u0A30\u0A32\u0A33\u0A35\u0A36\u0A38\u0A39\u0A59-\u0A5C\u0A5E\u0A72-\u0A74\u0A85-\u0A8D\u0A8F-\u0A91\u0A93-\u0AA8\u0AAA-\u0AB0\u0AB2\u0AB3\u0AB5-\u0AB9\u0ABD\u0AD0\u0AE0\u0AE1\u0B05-\u0B0C\u0B0F\u0B10\u0B13-\u0B28\u0B2A-\u0B30\u0B32\u0B33\u0B35-\u0B39\u0B3D\u0B5C\u0B5D\u0B5F-\u0B61\u0B71\u0B83\u0B85-\u0B8A\u0B8E-\u0B90\u0B92-\u0B95\u0B99\u0B9A\u0B9C\u0B9E\u0B9F\u0BA3\u0BA4\u0BA8-\u0BAA\u0BAE-\u0BB9\u0BD0\u0C05-\u0C0C\u0C0E-\u0C10\u0C12-\u0C28\u0C2A-\u0C33\u0C35-\u0C39\u0C3D\u0C58\u0C59\u0C60\u0C61\u0C85-\u0C8C\u0C8E-\u0C90\u0C92-\u0CA8\u0CAA-\u0CB3\u0CB5-\u0CB9\u0CBD\u0CDE\u0CE0\u0CE1\u0CF1\u0CF2\u0D05-\u0D0C\u0D0E-\u0D10\u0D12-\u0D3A\u0D3D\u0D4E\u0D60\u0D61\u0D7A-\u0D7F\u0D85-\u0D96\u0D9A-\u0DB1\u0DB3-\u0DBB\u0DBD\u0DC0-\u0DC6\u0E01-\u0E30\u0E32\u0E33\u0E40-\u0E46\u0E81\u0E82\u0E84\u0E87\u0E88\u0E8A\u0E8D\u0E94-\u0E97\u0E99-\u0E9F\u0EA1-\u0EA3\u0EA5\u0EA7\u0EAA\u0EAB\u0EAD-\u0EB0\u0EB2\u0EB3\u0EBD\u0EC0-\u0EC4\u0EC6\u0EDC-\u0EDF\u0F00\u0F40-\u0F47\u0F49-\u0F6C\u0F88-\u0F8C\u1000-\u102A\u103F\u1050-\u1055\u105A-\u105D\u1061\u1065\u1066\u106E-\u1070\u1075-\u1081\u108E\u10A0-\u10C5\u10C7\u10CD\u10D0-\u10FA\u10FC-\u1248\u124A-\u124D\u1250-\u1256\u1258\u125A-\u125D\u1260-\u1288\u128A-\u128D\u1290-\u12B0\u12B2-\u12B5\u12B8-\u12BE\u12C0\u12C2-\u12C5\u12C8-\u12D6\u12D8-\u1310\u1312-\u1315\u1318-\u135A\u1380-\u138F\u13A0-\u13F4\u1401-\u166C\u166F-\u167F\u1681-\u169A\u16A0-\u16EA\u16EE-\u16F0\u1700-\u170C\u170E-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176C\u176E-\u1770\u1780-\u17B3\u17D7\u17DC\u1820-\u1877\u1880-\u18A8\u18AA\u18B0-\u18F5\u1900-\u191C\u1950-\u196D\u1970-\u1974\u1980-\u19AB\u19C1-\u19C7\u1A00-\u1A16\u1A20-\u1A54\u1AA7\u1B05-\u1B33\u1B45-\u1B4B\u1B83-\u1BA0\u1BAE\u1BAF\u1BBA-\u1BE5\u1C00-\u1C23\u1C4D-\u1C4F\u1C5A-\u1C7D\u1CE9-\u1CEC\u1CEE-\u1CF1\u1CF5\u1CF6\u1D00-\u1DBF\u1E00-\u1F15\u1F18-\u1F1D\u1F20-\u1F45\u1F48-\u1F4D\u1F50-\u1F57\u1F59\u1F5B\u1F5D\u1F5F-\u1F7D\u1F80-\u1FB4\u1FB6-\u1FBC\u1FBE\u1FC2-\u1FC4\u1FC6-\u1FCC\u1FD0-\u1FD3\u1FD6-\u1FDB\u1FE0-\u1FEC\u1FF2-\u1FF4\u1FF6-\u1FFC\u2071\u207F\u2090-\u209C\u2102\u2107\u210A-\u2113\u2115\u2119-\u211D\u2124\u2126\u2128\u212A-\u212D\u212F-\u2139\u213C-\u213F\u2145-\u2149\u214E\u2160-\u2188\u2C00-\u2C2E\u2C30-\u2C5E\u2C60-\u2CE4\u2CEB-\u2CEE\u2CF2\u2CF3\u2D00-\u2D25\u2D27\u2D2D\u2D30-\u2D67\u2D6F\u2D80-\u2D96\u2DA0-\u2DA6\u2DA8-\u2DAE\u2DB0-\u2DB6\u2DB8-\u2DBE\u2DC0-\u2DC6\u2DC8-\u2DCE\u2DD0-\u2DD6\u2DD8-\u2DDE\u2E2F\u3005-\u3007\u3021-\u3029\u3031-\u3035\u3038-\u303C\u3041-\u3096\u309D-\u309F\u30A1-\u30FA\u30FC-\u30FF\u3105-\u312D\u3131-\u318E\u31A0-\u31BA\u31F0-\u31FF\u3400-\u4DB5\u4E00-\u9FCC\uA000-\uA48C\uA4D0-\uA4FD\uA500-\uA60C\uA610-\uA61F\uA62A\uA62B\uA640-\uA66E\uA67F-\uA697\uA6A0-\uA6EF\uA717-\uA71F\uA722-\uA788\uA78B-\uA78E\uA790-\uA793\uA7A0-\uA7AA\uA7F8-\uA801\uA803-\uA805\uA807-\uA80A\uA80C-\uA822\uA840-\uA873\uA882-\uA8B3\uA8F2-\uA8F7\uA8FB\uA90A-\uA925\uA930-\uA946\uA960-\uA97C\uA984-\uA9B2\uA9CF\uAA00-\uAA28\uAA40-\uAA42\uAA44-\uAA4B\uAA60-\uAA76\uAA7A\uAA80-\uAAAF\uAAB1\uAAB5\uAAB6\uAAB9-\uAABD\uAAC0\uAAC2\uAADB-\uAADD\uAAE0-\uAAEA\uAAF2-\uAAF4\uAB01-\uAB06\uAB09-\uAB0E\uAB11-\uAB16\uAB20-\uAB26\uAB28-\uAB2E\uABC0-\uABE2\uAC00-\uD7A3\uD7B0-\uD7C6\uD7CB-\uD7FB\uF900-\uFA6D\uFA70-\uFAD9\uFB00-\uFB06\uFB13-\uFB17\uFB1D\uFB1F-\uFB28\uFB2A-\uFB36\uFB38-\uFB3C\uFB3E\uFB40\uFB41\uFB43\uFB44\uFB46-\uFBB1\uFBD3-\uFD3D\uFD50-\uFD8F\uFD92-\uFDC7\uFDF0-\uFDFB\uFE70-\uFE74\uFE76-\uFEFC\uFF21-\uFF3A\uFF41-\uFF5A\uFF66-\uFFBE\uFFC2-\uFFC7\uFFCA-\uFFCF\uFFD2-\uFFD7\uFFDA-\uFFDC]'),
        NonAsciiIdentifierPart: new RegExp('[\xAA\xB5\xBA\xC0-\xD6\xD8-\xF6\xF8-\u02C1\u02C6-\u02D1\u02E0-\u02E4\u02EC\u02EE\u0300-\u0374\u0376\u0377\u037A-\u037D\u0386\u0388-\u038A\u038C\u038E-\u03A1\u03A3-\u03F5\u03F7-\u0481\u0483-\u0487\u048A-\u0527\u0531-\u0556\u0559\u0561-\u0587\u0591-\u05BD\u05BF\u05C1\u05C2\u05C4\u05C5\u05C7\u05D0-\u05EA\u05F0-\u05F2\u0610-\u061A\u0620-\u0669\u066E-\u06D3\u06D5-\u06DC\u06DF-\u06E8\u06EA-\u06FC\u06FF\u0710-\u074A\u074D-\u07B1\u07C0-\u07F5\u07FA\u0800-\u082D\u0840-\u085B\u08A0\u08A2-\u08AC\u08E4-\u08FE\u0900-\u0963\u0966-\u096F\u0971-\u0977\u0979-\u097F\u0981-\u0983\u0985-\u098C\u098F\u0990\u0993-\u09A8\u09AA-\u09B0\u09B2\u09B6-\u09B9\u09BC-\u09C4\u09C7\u09C8\u09CB-\u09CE\u09D7\u09DC\u09DD\u09DF-\u09E3\u09E6-\u09F1\u0A01-\u0A03\u0A05-\u0A0A\u0A0F\u0A10\u0A13-\u0A28\u0A2A-\u0A30\u0A32\u0A33\u0A35\u0A36\u0A38\u0A39\u0A3C\u0A3E-\u0A42\u0A47\u0A48\u0A4B-\u0A4D\u0A51\u0A59-\u0A5C\u0A5E\u0A66-\u0A75\u0A81-\u0A83\u0A85-\u0A8D\u0A8F-\u0A91\u0A93-\u0AA8\u0AAA-\u0AB0\u0AB2\u0AB3\u0AB5-\u0AB9\u0ABC-\u0AC5\u0AC7-\u0AC9\u0ACB-\u0ACD\u0AD0\u0AE0-\u0AE3\u0AE6-\u0AEF\u0B01-\u0B03\u0B05-\u0B0C\u0B0F\u0B10\u0B13-\u0B28\u0B2A-\u0B30\u0B32\u0B33\u0B35-\u0B39\u0B3C-\u0B44\u0B47\u0B48\u0B4B-\u0B4D\u0B56\u0B57\u0B5C\u0B5D\u0B5F-\u0B63\u0B66-\u0B6F\u0B71\u0B82\u0B83\u0B85-\u0B8A\u0B8E-\u0B90\u0B92-\u0B95\u0B99\u0B9A\u0B9C\u0B9E\u0B9F\u0BA3\u0BA4\u0BA8-\u0BAA\u0BAE-\u0BB9\u0BBE-\u0BC2\u0BC6-\u0BC8\u0BCA-\u0BCD\u0BD0\u0BD7\u0BE6-\u0BEF\u0C01-\u0C03\u0C05-\u0C0C\u0C0E-\u0C10\u0C12-\u0C28\u0C2A-\u0C33\u0C35-\u0C39\u0C3D-\u0C44\u0C46-\u0C48\u0C4A-\u0C4D\u0C55\u0C56\u0C58\u0C59\u0C60-\u0C63\u0C66-\u0C6F\u0C82\u0C83\u0C85-\u0C8C\u0C8E-\u0C90\u0C92-\u0CA8\u0CAA-\u0CB3\u0CB5-\u0CB9\u0CBC-\u0CC4\u0CC6-\u0CC8\u0CCA-\u0CCD\u0CD5\u0CD6\u0CDE\u0CE0-\u0CE3\u0CE6-\u0CEF\u0CF1\u0CF2\u0D02\u0D03\u0D05-\u0D0C\u0D0E-\u0D10\u0D12-\u0D3A\u0D3D-\u0D44\u0D46-\u0D48\u0D4A-\u0D4E\u0D57\u0D60-\u0D63\u0D66-\u0D6F\u0D7A-\u0D7F\u0D82\u0D83\u0D85-\u0D96\u0D9A-\u0DB1\u0DB3-\u0DBB\u0DBD\u0DC0-\u0DC6\u0DCA\u0DCF-\u0DD4\u0DD6\u0DD8-\u0DDF\u0DF2\u0DF3\u0E01-\u0E3A\u0E40-\u0E4E\u0E50-\u0E59\u0E81\u0E82\u0E84\u0E87\u0E88\u0E8A\u0E8D\u0E94-\u0E97\u0E99-\u0E9F\u0EA1-\u0EA3\u0EA5\u0EA7\u0EAA\u0EAB\u0EAD-\u0EB9\u0EBB-\u0EBD\u0EC0-\u0EC4\u0EC6\u0EC8-\u0ECD\u0ED0-\u0ED9\u0EDC-\u0EDF\u0F00\u0F18\u0F19\u0F20-\u0F29\u0F35\u0F37\u0F39\u0F3E-\u0F47\u0F49-\u0F6C\u0F71-\u0F84\u0F86-\u0F97\u0F99-\u0FBC\u0FC6\u1000-\u1049\u1050-\u109D\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\u135D-\u135F\u1380-\u138F\u13A0-\u13F4\u1401-\u166C\u166F-\u167F\u1681-\u169A\u16A0-\u16EA\u16EE-\u16F0\u1700-\u170C\u170E-\u1714\u1720-\u1734\u1740-\u1753\u1760-\u176C\u176E-\u1770\u1772\u1773\u1780-\u17D3\u17D7\u17DC\u17DD\u17E0-\u17E9\u180B-\u180D\u1810-\u1819\u1820-\u1877\u1880-\u18AA\u18B0-\u18F5\u1900-\u191C\u1920-\u192B\u1930-\u193B\u1946-\u196D\u1970-\u1974\u1980-\u19AB\u19B0-\u19C9\u19D0-\u19D9\u1A00-\u1A1B\u1A20-\u1A5E\u1A60-\u1A7C\u1A7F-\u1A89\u1A90-\u1A99\u1AA7\u1B00-\u1B4B\u1B50-\u1B59\u1B6B-\u1B73\u1B80-\u1BF3\u1C00-\u1C37\u1C40-\u1C49\u1C4D-\u1C7D\u1CD0-\u1CD2\u1CD4-\u1CF6\u1D00-\u1DE6\u1DFC-\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\u200C\u200D\u203F\u2040\u2054\u2071\u207F\u2090-\u209C\u20D0-\u20DC\u20E1\u20E5-\u20F0\u2102\u2107\u210A-\u2113\u2115\u2119-\u211D\u2124\u2126\u2128\u212A-\u212D\u212F-\u2139\u213C-\u213F\u2145-\u2149\u214E\u2160-\u2188\u2C00-\u2C2E\u2C30-\u2C5E\u2C60-\u2CE4\u2CEB-\u2CF3\u2D00-\u2D25\u2D27\u2D2D\u2D30-\u2D67\u2D6F\u2D7F-\u2D96\u2DA0-\u2DA6\u2DA8-\u2DAE\u2DB0-\u2DB6\u2DB8-\u2DBE\u2DC0-\u2DC6\u2DC8-\u2DCE\u2DD0-\u2DD6\u2DD8-\u2DDE\u2DE0-\u2DFF\u2E2F\u3005-\u3007\u3021-\u302F\u3031-\u3035\u3038-\u303C\u3041-\u3096\u3099\u309A\u309D-\u309F\u30A1-\u30FA\u30FC-\u30FF\u3105-\u312D\u3131-\u318E\u31A0-\u31BA\u31F0-\u31FF\u3400-\u4DB5\u4E00-\u9FCC\uA000-\uA48C\uA4D0-\uA4FD\uA500-\uA60C\uA610-\uA62B\uA640-\uA66F\uA674-\uA67D\uA67F-\uA697\uA69F-\uA6F1\uA717-\uA71F\uA722-\uA788\uA78B-\uA78E\uA790-\uA793\uA7A0-\uA7AA\uA7F8-\uA827\uA840-\uA873\uA880-\uA8C4\uA8D0-\uA8D9\uA8E0-\uA8F7\uA8FB\uA900-\uA92D\uA930-\uA953\uA960-\uA97C\uA980-\uA9C0\uA9CF-\uA9D9\uAA00-\uAA36\uAA40-\uAA4D\uAA50-\uAA59\uAA60-\uAA76\uAA7A\uAA7B\uAA80-\uAAC2\uAADB-\uAADD\uAAE0-\uAAEF\uAAF2-\uAAF6\uAB01-\uAB06\uAB09-\uAB0E\uAB11-\uAB16\uAB20-\uAB26\uAB28-\uAB2E\uABC0-\uABEA\uABEC\uABED\uABF0-\uABF9\uAC00-\uD7A3\uD7B0-\uD7C6\uD7CB-\uD7FB\uF900-\uFA6D\uFA70-\uFAD9\uFB00-\uFB06\uFB13-\uFB17\uFB1D-\uFB28\uFB2A-\uFB36\uFB38-\uFB3C\uFB3E\uFB40\uFB41\uFB43\uFB44\uFB46-\uFBB1\uFBD3-\uFD3D\uFD50-\uFD8F\uFD92-\uFDC7\uFDF0-\uFDFB\uFE00-\uFE0F\uFE20-\uFE26\uFE33\uFE34\uFE4D-\uFE4F\uFE70-\uFE74\uFE76-\uFEFC\uFF10-\uFF19\uFF21-\uFF3A\uFF3F\uFF41-\uFF5A\uFF66-\uFFBE\uFFC2-\uFFC7\uFFCA-\uFFCF\uFFD2-\uFFD7\uFFDA-\uFFDC]')
    };

    // 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 >= 48 && ch <= 57);   // 0..9
    }

    function isHexDigit(ch) {
        return '0123456789abcdefABCDEF'.indexOf(ch) >= 0;
    }

    function isOctalDigit(ch) {
        return '01234567'.indexOf(ch) >= 0;
    }


    // 7.2 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);
    }

    // 7.3 Line Terminators

    function isLineTerminator(ch) {
        return (ch === 0x0A) || (ch === 0x0D) || (ch === 0x2028) || (ch === 0x2029);
    }

    // 7.6 Identifier Names and Identifiers

    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(String.fromCharCode(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(String.fromCharCode(ch)));
    }

    // 7.6.1.2 Future Reserved Words

    function isFutureReservedWord(id) {
        switch (id) {
        case 'class':
        case 'enum':
        case 'export':
        case 'extends':
        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';
    }

    // 7.6.1.1 Keywords

    function isKeyword(id) {
        if (strict && isStrictModeReservedWord(id)) {
            return true;
        }

        // 'const' is specialized as Keyword in V8.
        // 'yield' and 'let' are for compatiblity 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;
        }
    }

    // 7.4 Comments

    function addComment(type, value, start, end, loc) {
        var comment, attacher;

        assert(typeof start === 'number', 'Comment must have valid position');

        // Because the way the actual token is scanned, often the comments
        // (if any) are skipped twice during the lexical analysis.
        // Thus, we need to skip adding a comment if the comment array already
        // handled it.
        if (state.lastCommentStart >= start) {
            return;
        }
        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)) {
                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;
                }
                ++lineNumber;
                ++index;
                lineStart = index;
                if (index >= length) {
                    throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
                }
            } 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;
            }
        }

        throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
    }

    function skipComment() {
        var ch, start;

        start = (index === 0);
        while (index < length) {
            ch = source.charCodeAt(index);

            if (isWhiteSpace(ch)) {
                ++index;
            } else if (isLineTerminator(ch)) {
                ++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 getEscapedIdentifier() {
        var ch, id;

        ch = source.charCodeAt(index++);
        id = String.fromCharCode(ch);

        // '\u' (U+005C, U+0075) denotes an escaped character.
        if (ch === 0x5C) {
            if (source.charCodeAt(index) !== 0x75) {
                throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
            }
            ++index;
            ch = scanHexEscape('u');
            if (!ch || ch === '\\' || !isIdentifierStart(ch.charCodeAt(0))) {
                throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
            }
            id = ch;
        }

        while (index < length) {
            ch = source.charCodeAt(index);
            if (!isIdentifierPart(ch)) {
                break;
            }
            ++index;
            id += String.fromCharCode(ch);

            // '\u' (U+005C, U+0075) denotes an escaped character.
            if (ch === 0x5C) {
                id = id.substr(0, id.length - 1);
                if (source.charCodeAt(index) !== 0x75) {
                    throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
                }
                ++index;
                ch = scanHexEscape('u');
                if (!ch || ch === '\\' || !isIdentifierPart(ch.charCodeAt(0))) {
                    throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
                }
                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 getEscapedIdentifier();
            }
            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) ? getEscapedIdentifier() : 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
        };
    }


    // 7.7 Punctuators

    function scanPunctuator() {
        var start = index,
            code = source.charCodeAt(index),
            code2,
            ch1 = source[index],
            ch2,
            ch3,
            ch4;

        switch (code) {

        // Check for most common single-character punctuators.
        case 0x2E:  // . dot
        case 0x28:  // ( open bracket
        case 0x29:  // ) close bracket
        case 0x3B:  // ; semicolon
        case 0x2C:  // , comma
        case 0x7B:  // { open curly brace
        case 0x7D:  // } close curly brace
        case 0x5B:  // [
        case 0x5D:  // ]
        case 0x3A:  // :
        case 0x3F:  // ?
        case 0x7E:  // ~
            ++index;
            if (extra.tokenize) {
                if (code === 0x28) {
                    extra.openParenToken = extra.tokens.length;
                } else if (code === 0x7B) {
                    extra.openCurlyToken = extra.tokens.length;
                }
            }
            return {
                type: Token.Punctuator,
                value: String.fromCharCode(code),
                lineNumber: lineNumber,
                lineStart: lineStart,
                start: start,
                end: index
            };

        default:
            code2 = source.charCodeAt(index + 1);

            // '=' (U+003D) marks an assignment or comparison operator.
            if (code2 === 0x3D) {
                switch (code) {
                case 0x2B:  // +
                case 0x2D:  // -
                case 0x2F:  // /
                case 0x3C:  // <
                case 0x3E:  // >
                case 0x5E:  // ^
                case 0x7C:  // |
                case 0x25:  // %
                case 0x26:  // &
                case 0x2A:  // *
                    index += 2;
                    return {
                        type: Token.Punctuator,
                        value: String.fromCharCode(code) + String.fromCharCode(code2),
                        lineNumber: lineNumber,
                        lineStart: lineStart,
                        start: start,
                        end: index
                    };

                case 0x21: // !
                case 0x3D: // =
                    index += 2;

                    // !== and ===
                    if (source.charCodeAt(index) === 0x3D) {
                        ++index;
                    }
                    return {
                        type: Token.Punctuator,
                        value: source.slice(start, index),
                        lineNumber: lineNumber,
                        lineStart: lineStart,
                        start: start,
                        end: index
                    };
                }
            }
        }

        // 4-character punctuator: >>>=

        ch4 = source.substr(index, 4);

        if (ch4 === '>>>=') {
            index += 4;
            return {
                type: Token.Punctuator,
                value: ch4,
                lineNumber: lineNumber,
                lineStart: lineStart,
                start: start,
                end: index
            };
        }

        // 3-character punctuators: === !== >>> <<= >>=

        ch3 = ch4.substr(0, 3);

        if (ch3 === '>>>' || ch3 === '<<=' || ch3 === '>>=') {
            index += 3;
            return {
                type: Token.Punctuator,
                value: ch3,
                lineNumber: lineNumber,
                lineStart: lineStart,
                start: start,
                end: index
            };
        }

        // Other 2-character punctuators: ++ -- << >> && ||
        ch2 = ch3.substr(0, 2);

        if ((ch1 === ch2[1] && ('+-<>&|'.indexOf(ch1) >= 0)) || ch2 === '=>') {
            index += 2;
            return {
                type: Token.Punctuator,
                value: ch2,
                lineNumber: lineNumber,
                lineStart: lineStart,
                start: start,
                end: index
            };
        }

        // 1-character punctuators: < > = ! + - * % & | ^ /
        if ('<>=!+-*%&|^/'.indexOf(ch1) >= 0) {
            ++index;
            return {
                type: Token.Punctuator,
                value: ch1,
                lineNumber: lineNumber,
                lineStart: lineStart,
                start: start,
                end: index
            };
        }

        throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
    }

    // 7.8.3 Numeric Literals

    function scanHexLiteral(start) {
        var number = '';

        while (index < length) {
            if (!isHexDigit(source[index])) {
                break;
            }
            number += source[index++];
        }

        if (number.length === 0) {
            throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
        }

        if (isIdentifierStart(source.charCodeAt(index))) {
            throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
        }

        return {
            type: Token.NumericLiteral,
            value: parseInt('0x' + number, 16),
            lineNumber: lineNumber,
            lineStart: lineStart,
            start: start,
            end: index
        };
    }

    function scanOctalLiteral(start) {
        var number = '0' + source[index++];
        while (index < length) {
            if (!isOctalDigit(source[index])) {
                break;
            }
            number += source[index++];
        }

        if (isIdentifierStart(source.charCodeAt(index)) || isDecimalDigit(source.charCodeAt(index))) {
            throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
        }

        return {
            type: Token.NumericLiteral,
            value: parseInt(number, 8),
            octal: true,
            lineNumber: lineNumber,
            lineStart: lineStart,
            start: start,
            end: index
        };
    }

    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'.
            if (number === '0') {
                if (ch === 'x' || ch === 'X') {
                    ++index;
                    return scanHexLiteral(start);
                }
                if (isOctalDigit(ch)) {
                    return scanOctalLiteral(start);
                }

                // decimal number starts with '0' such as '09' is illegal.
                if (ch && isDecimalDigit(ch.charCodeAt(0))) {
                    throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
                }
            }

            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 {
                throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
            }
        }

        if (isIdentifierStart(source.charCodeAt(index))) {
            throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
        }

        return {
            type: Token.NumericLiteral,
            value: parseFloat(number),
            lineNumber: lineNumber,
            lineStart: lineStart,
            start: start,
            end: index
        };
    }

    // 7.8.4 String Literals

    function scanStringLiteral() {
        var str = '', quote, start, ch, code, unescaped, restore, octal = false, startLineNumber, startLineStart;
        startLineNumber = lineNumber;
        startLineStart = lineStart;

        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':
                        restore = index;
                        unescaped = scanHexEscape(ch);
                        if (unescaped) {
                            str += unescaped;
                        } else {
                            index = restore;
                            str += ch;
                        }
                        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;

                    default:
                        if (isOctalDigit(ch)) {
                            code = '01234567'.indexOf(ch);

                            // \0 is not octal escape sequence
                            if (code !== 0) {
                                octal = true;
                            }

                            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++]);
                                }
                            }
                            str += String.fromCharCode(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 !== '') {
            throwError({}, Messages.UnexpectedToken, 'ILLEGAL');
        }

        return {
            type: Token.StringLiteral,
            value: str,
            octal: octal,
            startLineNumber: startLineNumber,
            startLineStart: startLineStart,
            lineNumber: lineNumber,
            lineStart: lineStart,
            start: start,
            end: index
        };
    }

    function testRegExp(pattern, flags) {
        var value;
        try {
            value = new RegExp(pattern, flags);
        } catch (e) {
            throwError({}, Messages.InvalidRegExp);
        }
        return value;
    }

    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))) {
                    throwError({}, Messages.UnterminatedRegExp);
                }
                str += ch;
            } else if (isLineTerminator(ch.charCodeAt(0))) {
                throwError({}, Messages.UnterminatedRegExp);
            } else if (classMarker) {
                if (ch === ']') {
                    classMarker = false;
                }
            } else {
                if (ch === '/') {
                    terminated = true;
                    break;
                } else if (ch === '[') {
                    classMarker = true;
                }
            }
        }

        if (!terminated) {
            throwError({}, 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';
                    }
                    throwErrorTolerant({}, Messages.UnexpectedToken, 'ILLEGAL');
                } else {
                    str += '\\';
                    throwErrorTolerant({}, Messages.UnexpectedToken, 'ILLEGAL');
                }
            } else {
                flags += ch;
                str += ch;
            }
        }

        return {
            value: flags,
            literal: str
        };
    }

    function scanRegExp() {
        var start, body, flags, pattern, value;

        lookahead = null;
        skipComment();
        start = index;

        body = scanRegExpBody();
        flags = scanRegExpFlags();
        value = testRegExp(body.value, flags.value);

        if (extra.tokenize) {
            return {
                type: Token.RegularExpression,
                value: value,
                lineNumber: lineNumber,
                lineStart: lineStart,
                start: start,
                end: index
            };
        }

        return {
            literal: body.literal + flags.literal,
            value: 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,
                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') {
            return collectRegex();
        }
        return scanPunctuator();
    }

    function advance() {
        var ch;

        skipComment();

        if (index >= length) {
            return {
                type: Token.EOF,
                lineNumber: lineNumber,
                lineStart: lineStart,
                start: index,
                end: index
            };
        }

        ch = source.charCodeAt(index);

        if (isIdentifierStart(ch)) {
            return scanIdentifier();
        }

        // Very common: ( and ) and ;
        if (ch === 0x28 || ch === 0x29 || ch === 0x3B) {
            return scanPunctuator();
        }

        // String literal starts with single quote (U+0027) or double quote (U+0022).
        if (ch === 0x27 || ch === 0x22) {
            return scanStringLiteral();
        }


        // Dot (.) U+002E can also start a floating-point number, hence the need
        // to check the next character.
        if (ch === 0x2E) {
            if (isDecimalDigit(source.charCodeAt(index + 1))) {
                return scanNumericLiteral();
            }
            return scanPunctuator();
        }

        if (isDecimalDigit(ch)) {
            return scanNumericLiteral();
        }

        // Slash (/) U+002F can also start a regex.
        if (extra.tokenize && ch === 0x2F) {
            return advanceSlash();
        }

        return scanPunctuator();
    }

    function collectToken() {
        var loc, token, range, value;

        skipComment();
        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);
            extra.tokens.push({
                type: TokenName[token.type],
                value: value,
                range: [token.start, token.end],
                loc: loc
            });
        }

        return token;
    }

    function lex() {
        var token;

        token = lookahead;
        index = token.end;
        lineNumber = token.lineNumber;
        lineStart = token.lineStart;

        lookahead = (typeof extra.tokens !== 'undefined') ? collectToken() : advance();

        index = token.end;
        lineNumber = token.lineNumber;
        lineStart = token.lineStart;

        return token;
    }

    function peek() {
        var pos, line, start;

        pos = index;
        line = lineNumber;
        start = lineStart;
        lookahead = (typeof extra.tokens !== 'undefined') ? collectToken() : advance();
        index = pos;
        lineNumber = line;
        lineStart = start;
    }

    function Position(line, column) {
        this.line = line;
        this.column = column;
    }

    function SourceLocation(startLine, startColumn, line, column) {
        this.start = new Position(startLine, startColumn);
        this.end = new Position(line, column);
    }

    SyntaxTreeDelegate = {

        name: 'SyntaxTree',

        processComment: function (node) {
            var lastChild, trailingComments;

            if (node.type === Syntax.Program) {
                if (node.body.length > 0) {
                    return;
                }
            }

            peek();

            if (extra.trailingComments.length > 0) {
                if (extra.trailingComments[0].range[0] >= node.range[1]) {
                    trailingComments = extra.trailingComments;
                    extra.trailingComments = [];
                } else {
                    extra.trailingComments.length = 0;
                }
            } else {
                if (extra.bottomRightStack.length > 0 &&
                        extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments &&
                        extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments[0].range[0] >= node.range[1]) {
                    trailingComments = extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments;
                    delete extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments;
                }
            }

            // Eating the stack.
            while (extra.bottomRightStack.length > 0 && extra.bottomRightStack[extra.bottomRightStack.length - 1].range[0] >= node.range[0]) {
                lastChild = extra.bottomRightStack.pop();
            }

            if (lastChild) {
                if (lastChild.leadingComments && lastChild.leadingComments[lastChild.leadingComments.length - 1].range[1] <= node.range[0]) {
                    node.leadingComments = lastChild.leadingComments;
                    delete lastChild.leadingComments;
                }
            } else if (extra.leadingComments.length > 0 && extra.leadingComments[extra.leadingComments.length - 1].range[1] <= node.range[0]) {
                node.leadingComments = extra.leadingComments;
                extra.leadingComments = [];
            }


            if (trailingComments) {
                node.trailingComments = trailingComments;
            }

            extra.bottomRightStack.push(node);
        },

        markEnd: function (node, startToken) {
            if (extra.range) {
                node.range = [startToken.start, index];
            }
            if (extra.loc) {
                node.loc = new SourceLocation(
                    startToken.startLineNumber === undefined ?  startToken.lineNumber : startToken.startLineNumber,
                    startToken.start - (startToken.startLineStart === undefined ?  startToken.lineStart : startToken.startLineStart),
                    lineNumber,
                    index - lineStart
                );
                this.postProcess(node);
            }

            if (extra.attachComment) {
                this.processComment(node);
            }
            return node;
        },

        postProcess: function (node) {
            if (extra.source) {
                node.loc.source = extra.source;
            }
            return node;
        },

        createArrayExpression: function (elements) {
            return {
                type: Syntax.ArrayExpression,
                elements: elements
            };
        },

        createAssignmentExpression: function (operator, left, right) {
            return {
                type: Syntax.AssignmentExpression,
                operator: operator,
                left: left,
                right: right
            };
        },

        createBinaryExpression: function (operator, left, right) {
            var type = (operator === '||' || operator === '&&') ? Syntax.LogicalExpression :
                        Syntax.BinaryExpression;
            return {
                type: type,
                operator: operator,
                left: left,
                right: right
            };
        },

        createBlockStatement: function (body) {
            return {
                type: Syntax.BlockStatement,
                body: body
            };
        },

        createBreakStatement: function (label) {
            return {
                type: Syntax.BreakStatement,
                label: label
            };
        },

        createCallExpression: function (callee, args) {
            return {
                type: Syntax.CallExpression,
                callee: callee,
                'arguments': args
            };
        },

        createCatchClause: function (param, body) {
            return {
                type: Syntax.CatchClause,
                param: param,
                body: body
            };
        },

        createConditionalExpression: function (test, consequent, alternate) {
            return {
                type: Syntax.ConditionalExpression,
                test: test,
                consequent: consequent,
                alternate: alternate
            };
        },

        createContinueStatement: function (label) {
            return {
                type: Syntax.ContinueStatement,
                label: label
            };
        },

        createDebuggerStatement: function () {
            return {
                type: Syntax.DebuggerStatement
            };
        },

        createDoWhileStatement: function (body, test) {
            return {
                type: Syntax.DoWhileStatement,
                body: body,
                test: test
            };
        },

        createEmptyStatement: function () {
            return {
                type: Syntax.EmptyStatement
            };
        },

        createExpressionStatement: function (expression) {
            return {
                type: Syntax.ExpressionStatement,
                expression: expression
            };
        },

        createForStatement: function (init, test, update, body) {
            return {
                type: Syntax.ForStatement,
                init: init,
                test: test,
                update: update,
                body: body
            };
        },

        createForInStatement: function (left, right, body) {
            return {
                type: Syntax.ForInStatement,
                left: left,
                right: right,
                body: body,
                each: false
            };
        },

        createFunctionDeclaration: function (id, params, defaults, body) {
            return {
                type: Syntax.FunctionDeclaration,
                id: id,
                params: params,
                defaults: defaults,
                body: body,
                rest: null,
                generator: false,
                expression: false
            };
        },

        createFunctionExpression: function (id, params, defaults, body) {
            return {
                type: Syntax.FunctionExpression,
                id: id,
                params: params,
                defaults: defaults,
                body: body,
                rest: null,
                generator: false,
                expression: false
            };
        },

        createIdentifier: function (name) {
            return {
                type: Syntax.Identifier,
                name: name
            };
        },

        createIfStatement: function (test, consequent, alternate) {
            return {
                type: Syntax.IfStatement,
                test: test,
                consequent: consequent,
                alternate: alternate
            };
        },

        createLabeledStatement: function (label, body) {
            return {
                type: Syntax.LabeledStatement,
                label: label,
                body: body
            };
        },

        createLiteral: function (token) {
            return {
                type: Syntax.Literal,
                value: token.value,
                raw: source.slice(token.start, token.end)
            };
        },

        createMemberExpression: function (accessor, object, property) {
            return {
                type: Syntax.MemberExpression,
                computed: accessor === '[',
                object: object,
                property: property
            };
        },

        createNewExpression: function (callee, args) {
            return {
                type: Syntax.NewExpression,
                callee: callee,
                'arguments': args
            };
        },

        createObjectExpression: function (properties) {
            return {
                type: Syntax.ObjectExpression,
                properties: properties
            };
        },

        createPostfixExpression: function (operator, argument) {
            return {
                type: Syntax.UpdateExpression,
                operator: operator,
                argument: argument,
                prefix: false
            };
        },

        createProgram: function (body) {
            return {
                type: Syntax.Program,
                body: body
            };
        },

        createProperty: function (kind, key, value) {
            return {
                type: Syntax.Property,
                key: key,
                value: value,
                kind: kind
            };
        },

        createReturnStatement: function (argument) {
            return {
                type: Syntax.ReturnStatement,
                argument: argument
            };
        },

        createSequenceExpression: function (expressions) {
            return {
                type: Syntax.SequenceExpression,
                expressions: expressions
            };
        },

        createSwitchCase: function (test, consequent) {
            return {
                type: Syntax.SwitchCase,
                test: test,
                consequent: consequent
            };
        },

        createSwitchStatement: function (discriminant, cases) {
            return {
                type: Syntax.SwitchStatement,
                discriminant: discriminant,
                cases: cases
            };
        },

        createThisExpression: function () {
            return {
                type: Syntax.ThisExpression
            };
        },

        createThrowStatement: function (argument) {
            return {
                type: Syntax.ThrowStatement,
                argument: argument
            };
        },

        createTryStatement: function (block, guardedHandlers, handlers, finalizer) {
            return {
                type: Syntax.TryStatement,
                block: block,
                guardedHandlers: guardedHandlers,
                handlers: handlers,
                finalizer: finalizer
            };
        },

        createUnaryExpression: function (operator, argument) {
            if (operator === '++' || operator === '--') {
                return {
                    type: Syntax.UpdateExpression,
                    operator: operator,
                    argument: argument,
                    prefix: true
                };
            }
            return {
                type: Syntax.UnaryExpression,
                operator: operator,
                argument: argument,
                prefix: true
            };
        },

        createVariableDeclaration: function (declarations, kind) {
            return {
                type: Syntax.VariableDeclaration,
                declarations: declarations,
                kind: kind
            };
        },

        createVariableDeclarator: function (id, init) {
            return {
                type: Syntax.VariableDeclarator,
                id: id,
                init: init
            };
        },

        createWhileStatement: function (test, body) {
            return {
                type: Syntax.WhileStatement,
                test: test,
                body: body
            };
        },

        createWithStatement: function (object, body) {
            return {
                type: Syntax.WithStatement,
                object: object,
                body: body
            };
        }
    };

    // Return true if there is a line terminator before the next token.

    function peekLineTerminator() {
        var pos, line, start, found;

        pos = index;
        line = lineNumber;
        start = lineStart;
        skipComment();
        found = lineNumber !== line;
        index = pos;
        lineNumber = line;
        lineStart = start;

        return found;
    }

    // Throw an exception

    function throwError(token, messageFormat) {
        var error,
            args = Array.prototype.slice.call(arguments, 2),
            msg = messageFormat.replace(
                /%(\d)/g,
                function (whole, index) {
                    assert(index < args.length, 'Message reference must be in range');
                    return args[index];
                }
            );

        if (typeof token.lineNumber === 'number') {
            error = new Error('Line ' + token.lineNumber + ': ' + msg);
            error.index = token.start;
            error.lineNumber = token.lineNumber;
            error.column = token.start - lineStart + 1;
        } else {
            error = new Error('Line ' + lineNumber + ': ' + msg);
            error.index = index;
            error.lineNumber = lineNumber;
            error.column = index - lineStart + 1;
        }

        error.description = msg;
        throw error;
    }

    function throwErrorTolerant() {
        try {
            throwError.apply(null, arguments);
        } catch (e) {
            if (extra.errors) {
                extra.errors.push(e);
            } else {
                throw e;
            }
        }
    }


    // Throw an exception because of the token.

    function throwUnexpected(token) {
        if (token.type === Token.EOF) {
            throwError(token, Messages.UnexpectedEOS);
        }

        if (token.type === Token.NumericLiteral) {
            throwError(token, Messages.UnexpectedNumber);
        }

        if (token.type === Token.StringLiteral) {
            throwError(token, Messages.UnexpectedString);
        }

        if (token.type === Token.Identifier) {
            throwError(token, Messages.UnexpectedIdentifier);
        }

        if (token.type === Token.Keyword) {
            if (isFutureReservedWord(token.value)) {
                throwError(token, Messages.UnexpectedReserved);
            } else if (strict && isStrictModeReservedWord(token.value)) {
                throwErrorTolerant(token, Messages.StrictReservedWord);
                return;
            }
            throwError(token, Messages.UnexpectedToken, token.value);
        }

        // BooleanLiteral, NullLiteral, or Punctuator.
        throwError(token, Messages.UnexpectedToken, token.value);
    }

    // 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) {
            throwUnexpected(token);
        }
    }

    // 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) {
            throwUnexpected(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 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() {
        var line;

        // Catch the very common case first: immediately a semicolon (U+003B).
        if (source.charCodeAt(index) === 0x3B || match(';')) {
            lex();
            return;
        }

        line = lineNumber;
        skipComment();
        if (lineNumber !== line) {
            return;
        }

        if (lookahead.type !== Token.EOF && !match('}')) {
            throwUnexpected(lookahead);
        }
    }

    // Return true if provided expression is LeftHandSideExpression

    function isLeftHandSide(expr) {
        return expr.type === Syntax.Identifier || expr.type === Syntax.MemberExpression;
    }

    // 11.1.4 Array Initialiser

    function parseArrayInitialiser() {
        var elements = [], startToken;

        startToken = lookahead;
        expect('[');

        while (!match(']')) {
            if (match(',')) {
                lex();
                elements.push(null);
            } else {
                elements.push(parseAssignmentExpression());

                if (!match(']')) {
                    expect(',');
                }
            }
        }

        lex();

        return delegate.markEnd(delegate.createArrayExpression(elements), startToken);
    }

    // 11.1.5 Object Initialiser

    function parsePropertyFunction(param, first) {
        var previousStrict, body, startToken;

        previousStrict = strict;
        startToken = lookahead;
        body = parseFunctionSourceElements();
        if (first && strict && isRestrictedWord(param[0].name)) {
            throwErrorTolerant(first, Messages.StrictParamName);
        }
        strict = previousStrict;
        return delegate.markEnd(delegate.createFunctionExpression(null, param, [], body), startToken);
    }

    function parseObjectPropertyKey() {
        var token, startToken;

        startToken = lookahead;
        token = lex();

        // Note: This function is called only from parseObjectProperty(), where
        // EOF and Punctuator tokens are already filtered out.

        if (token.type === Token.StringLiteral || token.type === Token.NumericLiteral) {
            if (strict && token.octal) {
                throwErrorTolerant(token, Messages.StrictOctalLiteral);
            }
            return delegate.markEnd(delegate.createLiteral(token), startToken);
        }

        return delegate.markEnd(delegate.createIdentifier(token.value), startToken);
    }

    function parseObjectProperty() {
        var token, key, id, value, param, startToken;

        token = lookahead;
        startToken = lookahead;

        if (token.type === Token.Identifier) {

            id = parseObjectPropertyKey();

            // Property Assignment: Getter and Setter.

            if (token.value === 'get' && !match(':')) {
                key = parseObjectPropertyKey();
                expect('(');
                expect(')');
                value = parsePropertyFunction([]);
                return delegate.markEnd(delegate.createProperty('get', key, value), startToken);
            }
            if (token.value === 'set' && !match(':')) {
                key = parseObjectPropertyKey();
                expect('(');
                token = lookahead;
                if (token.type !== Token.Identifier) {
                    expect(')');
                    throwErrorTolerant(token, Messages.UnexpectedToken, token.value);
                    value = parsePropertyFunction([]);
                } else {
                    param = [ parseVariableIdentifier() ];
                    expect(')');
                    value = parsePropertyFunction(param, token);
                }
                return delegate.markEnd(delegate.createProperty('set', key, value), startToken);
            }
            expect(':');
            value = parseAssignmentExpression();
            return delegate.markEnd(delegate.createProperty('init', id, value), startToken);
        }
        if (token.type === Token.EOF || token.type === Token.Punctuator) {
            throwUnexpected(token);
        } else {
            key = parseObjectPropertyKey();
            expect(':');
            value = parseAssignmentExpression();
            return delegate.markEnd(delegate.createProperty('init', key, value), startToken);
        }
    }

    function parseObjectInitialiser() {
        var properties = [], property, name, key, kind, map = {}, toString = String, startToken;

        startToken = lookahead;

        expect('{');

        while (!match('}')) {
            property = parseObjectProperty();

            if (property.key.type === Syntax.Identifier) {
                name = property.key.name;
            } else {
                name = toString(property.key.value);
            }
            kind = (property.kind === 'init') ? PropertyKind.Data : (property.kind === 'get') ? PropertyKind.Get : PropertyKind.Set;

            key = '$' + name;
            if (Object.prototype.hasOwnProperty.call(map, key)) {
                if (map[key] === PropertyKind.Data) {
                    if (strict && kind === PropertyKind.Data) {
                        throwErrorTolerant({}, Messages.StrictDuplicateProperty);
                    } else if (kind !== PropertyKind.Data) {
                        throwErrorTolerant({}, Messages.AccessorDataProperty);
                    }
                } else {
                    if (kind === PropertyKind.Data) {
                        throwErrorTolerant({}, Messages.AccessorDataProperty);
                    } else if (map[key] & kind) {
                        throwErrorTolerant({}, Messages.AccessorGetSet);
                    }
                }
                map[key] |= kind;
            } else {
                map[key] = kind;
            }

            properties.push(property);

            if (!match('}')) {
                expect(',');
            }
        }

        expect('}');

        return delegate.markEnd(delegate.createObjectExpression(properties), startToken);
    }

    // 11.1.6 The Grouping Operator

    function parseGroupExpression() {
        var expr;

        expect('(');

        expr = parseExpression();

        expect(')');

        return expr;
    }


    // 11.1 Primary Expressions

    function parsePrimaryExpression() {
        var type, token, expr, startToken;

        if (match('(')) {
            return parseGroupExpression();
        }

        if (match('[')) {
            return parseArrayInitialiser();
        }

        if (match('{')) {
            return parseObjectInitialiser();
        }

        type = lookahead.type;
        startToken = lookahead;

        if (type === Token.Identifier) {
            expr =  delegate.createIdentifier(lex().value);
        } else if (type === Token.StringLiteral || type === Token.NumericLiteral) {
            if (strict && lookahead.octal) {
                throwErrorTolerant(lookahead, Messages.StrictOctalLiteral);
            }
            expr = delegate.createLiteral(lex());
        } else if (type === Token.Keyword) {
            if (matchKeyword('function')) {
                return parseFunctionExpression();
            }
            if (matchKeyword('this')) {
                lex();
                expr = delegate.createThisExpression();
            } else {
                throwUnexpected(lex());
            }
        } else if (type === Token.BooleanLiteral) {
            token = lex();
            token.value = (token.value === 'true');
            expr = delegate.createLiteral(token);
        } else if (type === Token.NullLiteral) {
            token = lex();
            token.value = null;
            expr = delegate.createLiteral(token);
        } else if (match('/') || match('/=')) {
            if (typeof extra.tokens !== 'undefined') {
                expr = delegate.createLiteral(collectRegex());
            } else {
                expr = delegate.createLiteral(scanRegExp());
            }
            peek();
        } else {
            throwUnexpected(lex());
        }

        return delegate.markEnd(expr, startToken);
    }

    // 11.2 Left-Hand-Side Expressions

    function parseArguments() {
        var args = [];

        expect('(');

        if (!match(')')) {
            while (index < length) {
                args.push(parseAssignmentExpression());
                if (match(')')) {
                    break;
                }
                expect(',');
            }
        }

        expect(')');

        return args;
    }

    function parseNonComputedProperty() {
        var token, startToken;

        startToken = lookahead;
        token = lex();

        if (!isIdentifierName(token)) {
            throwUnexpected(token);
        }

        return delegate.markEnd(delegate.createIdentifier(token.value), startToken);
    }

    function parseNonComputedMember() {
        expect('.');

        return parseNonComputedProperty();
    }

    function parseComputedMember() {
        var expr;

        expect('[');

        expr = parseExpression();

        expect(']');

        return expr;
    }

    function parseNewExpression() {
        var callee, args, startToken;

        startToken = lookahead;
        expectKeyword('new');
        callee = parseLeftHandSideExpression();
        args = match('(') ? parseArguments() : [];

        return delegate.markEnd(delegate.createNewExpression(callee, args), startToken);
    }

    function parseLeftHandSideExpressionAllowCall() {
        var previousAllowIn, expr, args, property, startToken;

        startToken = lookahead;

        previousAllowIn = state.allowIn;
        state.allowIn = true;
        expr = matchKeyword('new') ? parseNewExpression() : parsePrimaryExpression();
        state.allowIn = previousAllowIn;

        for (;;) {
            if (match('.')) {
                property = parseNonComputedMember();
                expr = delegate.createMemberExpression('.', expr, property);
            } else if (match('(')) {
                args = parseArguments();
                expr = delegate.createCallExpression(expr, args);
            } else if (match('[')) {
                property = parseComputedMember();
                expr = delegate.createMemberExpression('[', expr, property);
            } else {
                break;
            }
            delegate.markEnd(expr, startToken);
        }

        return expr;
    }

    function parseLeftHandSideExpression() {
        var previousAllowIn, expr, property, startToken;

        startToken = lookahead;

        previousAllowIn = state.allowIn;
        expr = matchKeyword('new') ? parseNewExpression() : parsePrimaryExpression();
        state.allowIn = previousAllowIn;

        while (match('.') || match('[')) {
            if (match('[')) {
                property = parseComputedMember();
                expr = delegate.createMemberExpression('[', expr, property);
            } else {
                property = parseNonComputedMember();
                expr = delegate.createMemberExpression('.', expr, property);
            }
            delegate.markEnd(expr, startToken);
        }

        return expr;
    }

    // 11.3 Postfix Expressions

    function parsePostfixExpression() {
        var expr, token, startToken = lookahead;

        expr = parseLeftHandSideExpressionAllowCall();

        if (lookahead.type === Token.Punctuator) {
            if ((match('++') || match('--')) && !peekLineTerminator()) {
                // 11.3.1, 11.3.2
                if (strict && expr.type === Syntax.Identifier && isRestrictedWord(expr.name)) {
                    throwErrorTolerant({}, Messages.StrictLHSPostfix);
                }

                if (!isLeftHandSide(expr)) {
                    throwErrorTolerant({}, Messages.InvalidLHSInAssignment);
                }

                token = lex();
                expr = delegate.markEnd(delegate.createPostfixExpression(token.value, expr), startToken);
            }
        }

        return expr;
    }

    // 11.4 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 = parseUnaryExpression();
            // 11.4.4, 11.4.5
            if (strict && expr.type === Syntax.Identifier && isRestrictedWord(expr.name)) {
                throwErrorTolerant({}, Messages.StrictLHSPrefix);
            }

            if (!isLeftHandSide(expr)) {
                throwErrorTolerant({}, Messages.InvalidLHSInAssignment);
            }

            expr = delegate.createUnaryExpression(token.value, expr);
            expr = delegate.markEnd(expr, startToken);
        } else if (match('+') || match('-') || match('~') || match('!')) {
            startToken = lookahead;
            token = lex();
            expr = parseUnaryExpression();
            expr = delegate.createUnaryExpression(token.value, expr);
            expr = delegate.markEnd(expr, startToken);
        } else if (matchKeyword('delete') || matchKeyword('void') || matchKeyword('typeof')) {
            startToken = lookahead;
            token = lex();
            expr = parseUnaryExpression();
            expr = delegate.createUnaryExpression(token.value, expr);
            expr = delegate.markEnd(expr, startToken);
            if (strict && expr.operator === 'delete' && expr.argument.type === Syntax.Identifier) {
                throwErrorTolerant({}, Messages.StrictDelete);
            }
        } 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;
    }

    // 11.5 Multiplicative Operators
    // 11.6 Additive Operators
    // 11.7 Bitwise Shift Operators
    // 11.8 Relational Operators
    // 11.9 Equality Operators
    // 11.10 Binary Bitwise Operators
    // 11.11 Binary Logical Operators

    function parseBinaryExpression() {
        var marker, markers, expr, token, prec, stack, right, operator, left, i;

        marker = lookahead;
        left = parseUnaryExpression();

        token = lookahead;
        prec = binaryPrecedence(token, state.allowIn);
        if (prec === 0) {
            return left;
        }
        token.prec = prec;
        lex();

        markers = [marker, lookahead];
        right = 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();
                expr = delegate.createBinaryExpression(operator, left, right);
                markers.pop();
                marker = markers[markers.length - 1];
                delegate.markEnd(expr, marker);
                stack.push(expr);
            }

            // Shift.
            token = lex();
            token.prec = prec;
            stack.push(token);
            markers.push(lookahead);
            expr = parseUnaryExpression();
            stack.push(expr);
        }

        // Final reduce to clean-up the stack.
        i = stack.length - 1;
        expr = stack[i];
        markers.pop();
        while (i > 1) {
            expr = delegate.createBinaryExpression(stack[i - 1].value, stack[i - 2], expr);
            i -= 2;
            marker = markers.pop();
            delegate.markEnd(expr, marker);
        }

        return expr;
    }


    // 11.12 Conditional Operator

    function parseConditionalExpression() {
        var expr, previousAllowIn, consequent, alternate, startToken;

        startToken = lookahead;

        expr = parseBinaryExpression();

        if (match('?')) {
            lex();
            previousAllowIn = state.allowIn;
            state.allowIn = true;
            consequent = parseAssignmentExpression();
            state.allowIn = previousAllowIn;
            expect(':');
            alternate = parseAssignmentExpression();

            expr = delegate.createConditionalExpression(expr, consequent, alternate);
            delegate.markEnd(expr, startToken);
        }

        return expr;
    }

    // 11.13 Assignment Operators

    function parseAssignmentExpression() {
        var token, left, right, node, startToken;

        token = lookahead;
        startToken = lookahead;

        node = left = parseConditionalExpression();

        if (matchAssign()) {
            // LeftHandSideExpression
            if (!isLeftHandSide(left)) {
                throwErrorTolerant({}, Messages.InvalidLHSInAssignment);
            }

            // 11.13.1
            if (strict && left.type === Syntax.Identifier && isRestrictedWord(left.name)) {
                throwErrorTolerant(token, Messages.StrictLHSAssignment);
            }

            token = lex();
            right = parseAssignmentExpression();
            node = delegate.markEnd(delegate.createAssignmentExpression(token.value, left, right), startToken);
        }

        return node;
    }

    // 11.14 Comma Operator

    function parseExpression() {
        var expr, startToken = lookahead;

        expr = parseAssignmentExpression();

        if (match(',')) {
            expr = delegate.createSequenceExpression([ expr ]);

            while (index < length) {
                if (!match(',')) {
                    break;
                }
                lex();
                expr.expressions.push(parseAssignmentExpression());
            }

            delegate.markEnd(expr, startToken);
        }

        return expr;
    }

    // 12.1 Block

    function parseStatementList() {
        var list = [],
            statement;

        while (index < length) {
            if (match('}')) {
                break;
            }
            statement = parseSourceElement();
            if (typeof statement === 'undefined') {
                break;
            }
            list.push(statement);
        }

        return list;
    }

    function parseBlock() {
        var block, startToken;

        startToken = lookahead;
        expect('{');

        block = parseStatementList();

        expect('}');

        return delegate.markEnd(delegate.createBlockStatement(block), startToken);
    }

    // 12.2 Variable Statement

    function parseVariableIdentifier() {
        var token, startToken;

        startToken = lookahead;
        token = lex();

        if (token.type !== Token.Identifier) {
            throwUnexpected(token);
        }

        return delegate.markEnd(delegate.createIdentifier(token.value), startToken);
    }

    function parseVariableDeclaration(kind) {
        var init = null, id, startToken;

        startToken = lookahead;
        id = parseVariableIdentifier();

        // 12.2.1
        if (strict && isRestrictedWord(id.name)) {
            throwErrorTolerant({}, Messages.StrictVarName);
        }

        if (kind === 'const') {
            expect('=');
            init = parseAssignmentExpression();
        } else if (match('=')) {
            lex();
            init = parseAssignmentExpression();
        }

        return delegate.markEnd(delegate.createVariableDeclarator(id, init), startToken);
    }

    function parseVariableDeclarationList(kind) {
        var list = [];

        do {
            list.push(parseVariableDeclaration(kind));
            if (!match(',')) {
                break;
            }
            lex();
        } while (index < length);

        return list;
    }

    function parseVariableStatement() {
        var declarations;

        expectKeyword('var');

        declarations = parseVariableDeclarationList();

        consumeSemicolon();

        return delegate.createVariableDeclaration(declarations, 'var');
    }

    // kind may be `const` or `let`
    // Both are experimental and not in the specification yet.
    // see http://wiki.ecmascript.org/doku.php?id=harmony:const
    // and http://wiki.ecmascript.org/doku.php?id=harmony:let
    function parseConstLetDeclaration(kind) {
        var declarations, startToken;

        startToken = lookahead;

        expectKeyword(kind);

        declarations = parseVariableDeclarationList(kind);

        consumeSemicolon();

        return delegate.markEnd(delegate.createVariableDeclaration(declarations, kind), startToken);
    }

    // 12.3 Empty Statement

    function parseEmptyStatement() {
        expect(';');
        return delegate.createEmptyStatement();
    }

    // 12.4 Expression Statement

    function parseExpressionStatement() {
        var expr = parseExpression();
        consumeSemicolon();
        return delegate.createExpressionStatement(expr);
    }

    // 12.5 If statement

    function parseIfStatement() {
        var test, consequent, alternate;

        expectKeyword('if');

        expect('(');

        test = parseExpression();

        expect(')');

        consequent = parseStatement();

        if (matchKeyword('else')) {
            lex();
            alternate = parseStatement();
        } else {
            alternate = null;
        }

        return delegate.createIfStatement(test, consequent, alternate);
    }

    // 12.6 Iteration Statements

    function parseDoWhileStatement() {
        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 delegate.createDoWhileStatement(body, test);
    }

    function parseWhileStatement() {
        var test, body, oldInIteration;

        expectKeyword('while');

        expect('(');

        test = parseExpression();

        expect(')');

        oldInIteration = state.inIteration;
        state.inIteration = true;

        body = parseStatement();

        state.inIteration = oldInIteration;

        return delegate.createWhileStatement(test, body);
    }

    function parseForVariableDeclaration() {
        var token, declarations, startToken;

        startToken = lookahead;
        token = lex();
        declarations = parseVariableDeclarationList();

        return delegate.markEnd(delegate.createVariableDeclaration(declarations, token.value), startToken);
    }

    function parseForStatement() {
        var init, test, update, left, right, body, oldInIteration;

        init = test = update = null;

        expectKeyword('for');

        expect('(');

        if (match(';')) {
            lex();
        } else {
            if (matchKeyword('var') || matchKeyword('let')) {
                state.allowIn = false;
                init = parseForVariableDeclaration();
                state.allowIn = true;

                if (init.declarations.length === 1 && matchKeyword('in')) {
                    lex();
                    left = init;
                    right = parseExpression();
                    init = null;
                }
            } else {
                state.allowIn = false;
                init = parseExpression();
                state.allowIn = true;

                if (matchKeyword('in')) {
                    // LeftHandSideExpression
                    if (!isLeftHandSide(init)) {
                        throwErrorTolerant({}, Messages.InvalidLHSInForIn);
                    }

                    lex();
                    left = init;
                    right = parseExpression();
                    init = null;
                }
            }

            if (typeof left === 'undefined') {
                expect(';');
            }
        }

        if (typeof left === 'undefined') {

            if (!match(';')) {
                test = parseExpression();
            }
            expect(';');

            if (!match(')')) {
                update = parseExpression();
            }
        }

        expect(')');

        oldInIteration = state.inIteration;
        state.inIteration = true;

        body = parseStatement();

        state.inIteration = oldInIteration;

        return (typeof left === 'undefined') ?
                delegate.createForStatement(init, test, update, body) :
                delegate.createForInStatement(left, right, body);
    }

    // 12.7 The continue statement

    function parseContinueStatement() {
        var label = null, key;

        expectKeyword('continue');

        // Optimize the most common form: 'continue;'.
        if (source.charCodeAt(index) === 0x3B) {
            lex();

            if (!state.inIteration) {
                throwError({}, Messages.IllegalContinue);
            }

            return delegate.createContinueStatement(null);
        }

        if (peekLineTerminator()) {
            if (!state.inIteration) {
                throwError({}, Messages.IllegalContinue);
            }

            return delegate.createContinueStatement(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 delegate.createContinueStatement(label);
    }

    // 12.8 The break statement

    function parseBreakStatement() {
        var label = null, key;

        expectKeyword('break');

        // Catch the very common case first: immediately a semicolon (U+003B).
        if (source.charCodeAt(index) === 0x3B) {
            lex();

            if (!(state.inIteration || state.inSwitch)) {
                throwError({}, Messages.IllegalBreak);
            }

            return delegate.createBreakStatement(null);
        }

        if (peekLineTerminator()) {
            if (!(state.inIteration || state.inSwitch)) {
                throwError({}, Messages.IllegalBreak);
            }

            return delegate.createBreakStatement(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 delegate.createBreakStatement(label);
    }

    // 12.9 The return statement

    function parseReturnStatement() {
        var argument = null;

        expectKeyword('return');

        if (!state.inFunctionBody) {
            throwErrorTolerant({}, Messages.IllegalReturn);
        }

        // 'return' followed by a space and an identifier is very common.
        if (source.charCodeAt(index) === 0x20) {
            if (isIdentifierStart(source.charCodeAt(index + 1))) {
                argument = parseExpression();
                consumeSemicolon();
                return delegate.createReturnStatement(argument);
            }
        }

        if (peekLineTerminator()) {
            return delegate.createReturnStatement(null);
        }

        if (!match(';')) {
            if (!match('}') && lookahead.type !== Token.EOF) {
                argument = parseExpression();
            }
        }

        consumeSemicolon();

        return delegate.createReturnStatement(argument);
    }

    // 12.10 The with statement

    function parseWithStatement() {
        var object, body;

        if (strict) {
            // TODO(ikarienator): Should we update the test cases instead?
            skipComment();
            throwErrorTolerant({}, Messages.StrictModeWith);
        }

        expectKeyword('with');

        expect('(');

        object = parseExpression();

        expect(')');

        body = parseStatement();

        return delegate.createWithStatement(object, body);
    }

    // 12.10 The swith statement

    function parseSwitchCase() {
        var test, consequent = [], statement, startToken;

        startToken = lookahead;
        if (matchKeyword('default')) {
            lex();
            test = null;
        } else {
            expectKeyword('case');
            test = parseExpression();
        }
        expect(':');

        while (index < length) {
            if (match('}') || matchKeyword('default') || matchKeyword('case')) {
                break;
            }
            statement = parseStatement();
            consequent.push(statement);
        }

        return delegate.markEnd(delegate.createSwitchCase(test, consequent), startToken);
    }

    function parseSwitchStatement() {
        var discriminant, cases, clause, oldInSwitch, defaultFound;

        expectKeyword('switch');

        expect('(');

        discriminant = parseExpression();

        expect(')');

        expect('{');

        cases = [];

        if (match('}')) {
            lex();
            return delegate.createSwitchStatement(discriminant, cases);
        }

        oldInSwitch = state.inSwitch;
        state.inSwitch = true;
        defaultFound = false;

        while (index < 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 delegate.createSwitchStatement(discriminant, cases);
    }

    // 12.13 The throw statement

    function parseThrowStatement() {
        var argument;

        expectKeyword('throw');

        if (peekLineTerminator()) {
            throwError({}, Messages.NewlineAfterThrow);
        }

        argument = parseExpression();

        consumeSemicolon();

        return delegate.createThrowStatement(argument);
    }

    // 12.14 The try statement

    function parseCatchClause() {
        var param, body, startToken;

        startToken = lookahead;
        expectKeyword('catch');

        expect('(');
        if (match(')')) {
            throwUnexpected(lookahead);
        }

        param = parseVariableIdentifier();
        // 12.14.1
        if (strict && isRestrictedWord(param.name)) {
            throwErrorTolerant({}, Messages.StrictCatchVariable);
        }

        expect(')');
        body = parseBlock();
        return delegate.markEnd(delegate.createCatchClause(param, body), startToken);
    }

    function parseTryStatement() {
        var block, handlers = [], finalizer = null;

        expectKeyword('try');

        block = parseBlock();

        if (matchKeyword('catch')) {
            handlers.push(parseCatchClause());
        }

        if (matchKeyword('finally')) {
            lex();
            finalizer = parseBlock();
        }

        if (handlers.length === 0 && !finalizer) {
            throwError({}, Messages.NoCatchOrFinally);
        }

        return delegate.createTryStatement(block, [], handlers, finalizer);
    }

    // 12.15 The debugger statement

    function parseDebuggerStatement() {
        expectKeyword('debugger');

        consumeSemicolon();

        return delegate.createDebuggerStatement();
    }

    // 12 Statements

    function parseStatement() {
        var type = lookahead.type,
            expr,
            labeledBody,
            key,
            startToken;

        if (type === Token.EOF) {
            throwUnexpected(lookahead);
        }

        if (type === Token.Punctuator && lookahead.value === '{') {
            return parseBlock();
        }

        startToken = lookahead;

        if (type === Token.Punctuator) {
            switch (lookahead.value) {
            case ';':
                return delegate.markEnd(parseEmptyStatement(), startToken);
            case '(':
                return delegate.markEnd(parseExpressionStatement(), startToken);
            default:
                break;
            }
        }

        if (type === Token.Keyword) {
            switch (lookahead.value) {
            case 'break':
                return delegate.markEnd(parseBreakStatement(), startToken);
            case 'continue':
                return delegate.markEnd(parseContinueStatement(), startToken);
            case 'debugger':
                return delegate.markEnd(parseDebuggerStatement(), startToken);
            case 'do':
                return delegate.markEnd(parseDoWhileStatement(), startToken);
            case 'for':
                return delegate.markEnd(parseForStatement(), startToken);
            case 'function':
                return delegate.markEnd(parseFunctionDeclaration(), startToken);
            case 'if':
                return delegate.markEnd(parseIfStatement(), startToken);
            case 'return':
                return delegate.markEnd(parseReturnStatement(), startToken);
            case 'switch':
                return delegate.markEnd(parseSwitchStatement(), startToken);
            case 'throw':
                return delegate.markEnd(parseThrowStatement(), startToken);
            case 'try':
                return delegate.markEnd(parseTryStatement(), startToken);
            case 'var':
                return delegate.markEnd(parseVariableStatement(), startToken);
            case 'while':
                return delegate.markEnd(parseWhileStatement(), startToken);
            case 'with':
                return delegate.markEnd(parseWithStatement(), startToken);
            default:
                break;
            }
        }

        expr = parseExpression();

        // 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 delegate.markEnd(delegate.createLabeledStatement(expr, labeledBody), startToken);
        }

        consumeSemicolon();

        return delegate.markEnd(delegate.createExpressionStatement(expr), startToken);
    }

    // 13 Function Definition

    function parseFunctionSourceElements() {
        var sourceElement, sourceElements = [], token, directive, firstRestricted,
            oldLabelSet, oldInIteration, oldInSwitch, oldInFunctionBody, startToken;

        startToken = lookahead;
        expect('{');

        while (index < length) {
            if (lookahead.type !== Token.StringLiteral) {
                break;
            }
            token = lookahead;

            sourceElement = parseSourceElement();
            sourceElements.push(sourceElement);
            if (sourceElement.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) {
                    throwErrorTolerant(firstRestricted, Messages.StrictOctalLiteral);
                }
            } else {
                if (!firstRestricted && token.octal) {
                    firstRestricted = token;
                }
            }
        }

        oldLabelSet = state.labelSet;
        oldInIteration = state.inIteration;
        oldInSwitch = state.inSwitch;
        oldInFunctionBody = state.inFunctionBody;

        state.labelSet = {};
        state.inIteration = false;
        state.inSwitch = false;
        state.inFunctionBody = true;

        while (index < length) {
            if (match('}')) {
                break;
            }
            sourceElement = parseSourceElement();
            if (typeof sourceElement === 'undefined') {
                break;
            }
            sourceElements.push(sourceElement);
        }

        expect('}');

        state.labelSet = oldLabelSet;
        state.inIteration = oldInIteration;
        state.inSwitch = oldInSwitch;
        state.inFunctionBody = oldInFunctionBody;

        return delegate.markEnd(delegate.createBlockStatement(sourceElements), startToken);
    }

    function parseParams(firstRestricted) {
        var param, params = [], token, stricted, paramSet, key, message;
        expect('(');

        if (!match(')')) {
            paramSet = {};
            while (index < length) {
                token = lookahead;
                param = parseVariableIdentifier();
                key = '$' + token.value;
                if (strict) {
                    if (isRestrictedWord(token.value)) {
                        stricted = token;
                        message = Messages.StrictParamName;
                    }
                    if (Object.prototype.hasOwnProperty.call(paramSet, key)) {
                        stricted = token;
                        message = Messages.StrictParamDupe;
                    }
                } else if (!firstRestricted) {
                    if (isRestrictedWord(token.value)) {
                        firstRestricted = token;
                        message = Messages.StrictParamName;
                    } else if (isStrictModeReservedWord(token.value)) {
                        firstRestricted = token;
                        message = Messages.StrictReservedWord;
                    } else if (Object.prototype.hasOwnProperty.call(paramSet, key)) {
                        firstRestricted = token;
                        message = Messages.StrictParamDupe;
                    }
                }
                params.push(param);
                paramSet[key] = true;
                if (match(')')) {
                    break;
                }
                expect(',');
            }
        }

        expect(')');

        return {
            params: params,
            stricted: stricted,
            firstRestricted: firstRestricted,
            message: message
        };
    }

    function parseFunctionDeclaration() {
        var id, params = [], body, token, stricted, tmp, firstRestricted, message, previousStrict, startToken;

        startToken = lookahead;

        expectKeyword('function');
        token = lookahead;
        id = parseVariableIdentifier();
        if (strict) {
            if (isRestrictedWord(token.value)) {
                throwErrorTolerant(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;
        stricted = tmp.stricted;
        firstRestricted = tmp.firstRestricted;
        if (tmp.message) {
            message = tmp.message;
        }

        previousStrict = strict;
        body = parseFunctionSourceElements();
        if (strict && firstRestricted) {
            throwError(firstRestricted, message);
        }
        if (strict && stricted) {
            throwErrorTolerant(stricted, message);
        }
        strict = previousStrict;

        return delegate.markEnd(delegate.createFunctionDeclaration(id, params, [], body), startToken);
    }

    function parseFunctionExpression() {
        var token, id = null, stricted, firstRestricted, message, tmp, params = [], body, previousStrict, startToken;

        startToken = lookahead;
        expectKeyword('function');

        if (!match('(')) {
            token = lookahead;
            id = parseVariableIdentifier();
            if (strict) {
                if (isRestrictedWord(token.value)) {
                    throwErrorTolerant(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;
        stricted = tmp.stricted;
        firstRestricted = tmp.firstRestricted;
        if (tmp.message) {
            message = tmp.message;
        }

        previousStrict = strict;
        body = parseFunctionSourceElements();
        if (strict && firstRestricted) {
            throwError(firstRestricted, message);
        }
        if (strict && stricted) {
            throwErrorTolerant(stricted, message);
        }
        strict = previousStrict;

        return delegate.markEnd(delegate.createFunctionExpression(id, params, [], body), startToken);
    }

    // 14 Program

    function parseSourceElement() {
        if (lookahead.type === Token.Keyword) {
            switch (lookahead.value) {
            case 'const':
            case 'let':
                return parseConstLetDeclaration(lookahead.value);
            case 'function':
                return parseFunctionDeclaration();
            default:
                return parseStatement();
            }
        }

        if (lookahead.type !== Token.EOF) {
            return parseStatement();
        }
    }

    function parseSourceElements() {
        var sourceElement, sourceElements = [], token, directive, firstRestricted;

        while (index < length) {
            token = lookahead;
            if (token.type !== Token.StringLiteral) {
                break;
            }

            sourceElement = parseSourceElement();
            sourceElements.push(sourceElement);
            if (sourceElement.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) {
                    throwErrorTolerant(firstRestricted, Messages.StrictOctalLiteral);
                }
            } else {
                if (!firstRestricted && token.octal) {
                    firstRestricted = token;
                }
            }
        }

        while (index < length) {
            sourceElement = parseSourceElement();
            /* istanbul ignore if */
            if (typeof sourceElement === 'undefined') {
                break;
            }
            sourceElements.push(sourceElement);
        }
        return sourceElements;
    }

    function parseProgram() {
        var body, startToken;

        skipComment();
        peek();
        startToken = lookahead;
        strict = false;

        body = parseSourceElements();
        return delegate.markEnd(delegate.createProgram(body), startToken);
    }

    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 (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,
            token,
            tokens;

        toString = String;
        if (typeof code !== 'string' && !(code instanceof String)) {
            code = toString(code);
        }

        delegate = SyntaxTreeDelegate;
        source = code;
        index = 0;
        lineNumber = (source.length > 0) ? 1 : 0;
        lineStart = 0;
        length = source.length;
        lookahead = null;
        state = {
            allowIn: true,
            labelSet: {},
            inFunctionBody: false,
            inIteration: false,
            inSwitch: false,
            lastCommentStart: -1
        };

        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;
            }

            token = lex();
            while (lookahead.type !== Token.EOF) {
                try {
                    token = lex();
                } catch (lexError) {
                    token = lookahead;
                    if (extra.errors) {
                        extra.errors.push(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);
        }

        delegate = SyntaxTreeDelegate;
        source = code;
        index = 0;
        lineNumber = (source.length > 0) ? 1 : 0;
        lineStart = 0;
        length = source.length;
        lookahead = null;
        state = {
            allowIn: true,
            labelSet: {},
            inFunctionBody: false,
            inIteration: false,
            inSwitch: false,
            lastCommentStart: -1
        };

        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 = [];
            }
        }

        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 = '1.2.1';

    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 : */

},{}],10:[function(_dereq_,module,exports){
/*
  Copyright (C) 2012-2013 Yusuke Suzuki <utatane.tea@gmail.com>
  Copyright (C) 2012 Ariya Hidayat <ariya.hidayat@gmail.com>

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

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

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

    // Universal Module Definition (UMD) to support AMD, CommonJS/Node.js,
    // and plain browser loading,
    if (typeof define === 'function' && define.amd) {
        define(['exports'], factory);
    } else if (typeof exports !== 'undefined') {
        factory(exports);
    } else {
        factory((root.estraverse = {}));
    }
}(this, function (exports) {
    'use strict';

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

    Syntax = {
        AssignmentExpression: 'AssignmentExpression',
        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',
        DebuggerStatement: 'DebuggerStatement',
        DirectiveStatement: 'DirectiveStatement',
        DoWhileStatement: 'DoWhileStatement',
        EmptyStatement: 'EmptyStatement',
        ExpressionStatement: 'ExpressionStatement',
        ForStatement: 'ForStatement',
        ForInStatement: 'ForInStatement',
        FunctionDeclaration: 'FunctionDeclaration',
        FunctionExpression: 'FunctionExpression',
        Identifier: 'Identifier',
        IfStatement: 'IfStatement',
        Literal: 'Literal',
        LabeledStatement: 'LabeledStatement',
        LogicalExpression: 'LogicalExpression',
        MemberExpression: 'MemberExpression',
        MethodDefinition: 'MethodDefinition',
        NewExpression: 'NewExpression',
        ObjectExpression: 'ObjectExpression',
        ObjectPattern: 'ObjectPattern',
        Program: 'Program',
        Property: 'Property',
        ReturnStatement: 'ReturnStatement',
        SequenceExpression: 'SequenceExpression',
        SwitchStatement: 'SwitchStatement',
        SwitchCase: 'SwitchCase',
        ThisExpression: 'ThisExpression',
        ThrowStatement: 'ThrowStatement',
        TryStatement: 'TryStatement',
        UnaryExpression: 'UnaryExpression',
        UpdateExpression: 'UpdateExpression',
        VariableDeclaration: 'VariableDeclaration',
        VariableDeclarator: 'VariableDeclarator',
        WhileStatement: 'WhileStatement',
        WithStatement: 'WithStatement',
        YieldExpression: 'YieldExpression'
    };

    function ignoreJSHintError() { }

    isArray = Array.isArray;
    if (!isArray) {
        isArray = function isArray(array) {
            return Object.prototype.toString.call(array) === '[object Array]';
        };
    }

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

    function shallowCopy(obj) {
        var ret = {}, key;
        for (key in obj) {
            if (obj.hasOwnProperty(key)) {
                ret[key] = obj[key];
            }
        }
        return ret;
    }
    ignoreJSHintError(shallowCopy);

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

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

        len = array.length;
        i = 0;

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

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

        len = array.length;
        i = 0;

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

    VisitorKeys = {
        AssignmentExpression: ['left', 'right'],
        ArrayExpression: ['elements'],
        ArrayPattern: ['elements'],
        ArrowFunctionExpression: ['params', 'defaults', 'rest', 'body'],
        BlockStatement: ['body'],
        BinaryExpression: ['left', 'right'],
        BreakStatement: ['label'],
        CallExpression: ['callee', 'arguments'],
        CatchClause: ['param', 'body'],
        ClassBody: ['body'],
        ClassDeclaration: ['id', 'body', 'superClass'],
        ClassExpression: ['id', 'body', 'superClass'],
        ConditionalExpression: ['test', 'consequent', 'alternate'],
        ContinueStatement: ['label'],
        DebuggerStatement: [],
        DirectiveStatement: [],
        DoWhileStatement: ['body', 'test'],
        EmptyStatement: [],
        ExpressionStatement: ['expression'],
        ForStatement: ['init', 'test', 'update', 'body'],
        ForInStatement: ['left', 'right', 'body'],
        FunctionDeclaration: ['id', 'params', 'defaults', 'rest', 'body'],
        FunctionExpression: ['id', 'params', 'defaults', 'rest', 'body'],
        Identifier: [],
        IfStatement: ['test', 'consequent', 'alternate'],
        Literal: [],
        LabeledStatement: ['label', 'body'],
        LogicalExpression: ['left', 'right'],
        MemberExpression: ['object', 'property'],
        MethodDefinition: ['key', 'value'],
        NewExpression: ['callee', 'arguments'],
        ObjectExpression: ['properties'],
        ObjectPattern: ['properties'],
        Program: ['body'],
        Property: ['key', 'value'],
        ReturnStatement: ['argument'],
        SequenceExpression: ['expressions'],
        SwitchStatement: ['discriminant', 'cases'],
        SwitchCase: ['test', 'consequent'],
        ThisExpression: [],
        ThrowStatement: ['argument'],
        TryStatement: ['block', 'handlers', 'handler', 'guardedHandlers', 'finalizer'],
        UnaryExpression: ['argument'],
        UpdateExpression: ['argument'],
        VariableDeclaration: ['declarations'],
        VariableDeclarator: ['id', 'init'],
        WhileStatement: ['test', 'body'],
        WithStatement: ['object', 'body'],
        YieldExpression: ['argument']
    };

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

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

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

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

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

    function Controller() { }

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

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

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

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

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

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

        return result;
    };

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

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

        result = undefined;

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

        return result;
    };

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

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

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

    Controller.prototype.__initialize = function(root, visitor) {
        this.visitor = visitor;
        this.root = root;
        this.__worklist = [];
        this.__leavelist = [];
        this.__current = null;
        this.__state = null;
    };

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

        this.__initialize(root, visitor);

        sentinel = {};

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

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

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

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

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

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

            if (element.node) {

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

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

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

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

                node = element.node;
                nodeType = element.wrap || node.type;
                candidates = VisitorKeys[nodeType];

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

                    if (!isArray(candidate)) {
                        worklist.push(new Element(candidate, key, null, null));
                        continue;
                    }

                    current2 = candidate.length;
                    while ((current2 -= 1) >= 0) {
                        if (!candidate[current2]) {
                            continue;
                        }
                        if ((nodeType === Syntax.ObjectExpression || nodeType === Syntax.ObjectPattern) && 'properties' === candidates[current]) {
                            element = new Element(candidate[current2], [key, current2], 'Property', null);
                        } else {
                            element = new Element(candidate[current2], [key, current2], null, null);
                        }
                        worklist.push(element);
                    }
                }
            }
        }
    };

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

        this.__initialize(root, visitor);

        sentinel = {};

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

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

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

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

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

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

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

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

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

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

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

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

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

            nodeType = element.wrap || node.type;
            candidates = VisitorKeys[nodeType];

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

                if (!isArray(candidate)) {
                    worklist.push(new Element(candidate, key, null, new Reference(node, key)));
                    continue;
                }

                current2 = candidate.length;
                while ((current2 -= 1) >= 0) {
                    if (!candidate[current2]) {
                        continue;
                    }
                    if (nodeType === Syntax.ObjectExpression && 'properties' === candidates[current]) {
                        element = new Element(candidate[current2], [key, current2], 'Property', new Reference(candidate, current2));
                    } else {
                        element = new Element(candidate[current2], [key, current2], null, new Reference(candidate, current2));
                    }
                    worklist.push(element);
                }
            }
        }

        return outer.root;
    };

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

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

    function extendCommentRange(comment, tokens) {
        var target;

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

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

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

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

        return comment;
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        return tree;
    }

    exports.version = '1.3.3-dev';
    exports.Syntax = Syntax;
    exports.traverse = traverse;
    exports.replace = replace;
    exports.attachComments = attachComments;
    exports.VisitorKeys = VisitorKeys;
    exports.VisitorOption = VisitorOption;
    exports.Controller = Controller;
}));
/* vim: set sw=4 ts=4 et tw=80 : */

},{}],11:[function(_dereq_,module,exports){
module.exports = _dereq_('./javascript/diff_match_patch_uncompressed.js').diff_match_patch;

},{"./javascript/diff_match_patch_uncompressed.js":12}],12:[function(_dereq_,module,exports){
/**
 * Diff Match and Patch
 *
 * Copyright 2006 Google Inc.
 * http://code.google.com/p/google-diff-match-patch/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @fileoverview Computes the difference between two texts to create a patch.
 * Applies the patch onto another text, allowing for errors.
 * @author fraser@google.com (Neil Fraser)
 */

/**
 * Class containing the diff, match and patch methods.
 * @constructor
 */
function diff_match_patch() {

  // Defaults.
  // Redefine these in your program to override the defaults.

  // Number of seconds to map a diff before giving up (0 for infinity).
  this.Diff_Timeout = 1.0;
  // Cost of an empty edit operation in terms of edit characters.
  this.Diff_EditCost = 4;
  // At what point is no match declared (0.0 = perfection, 1.0 = very loose).
  this.Match_Threshold = 0.5;
  // How far to search for a match (0 = exact location, 1000+ = broad match).
  // A match this many characters away from the expected location will add
  // 1.0 to the score (0.0 is a perfect match).
  this.Match_Distance = 1000;
  // When deleting a large block of text (over ~64 characters), how close do
  // the contents have to be to match the expected contents. (0.0 = perfection,
  // 1.0 = very loose).  Note that Match_Threshold controls how closely the
  // end points of a delete need to match.
  this.Patch_DeleteThreshold = 0.5;
  // Chunk size for context length.
  this.Patch_Margin = 4;

  // The number of bits in an int.
  this.Match_MaxBits = 32;
}


//  DIFF FUNCTIONS


/**
 * The data structure representing a diff is an array of tuples:
 * [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']]
 * which means: delete 'Hello', add 'Goodbye' and keep ' world.'
 */
var DIFF_DELETE = -1;
var DIFF_INSERT = 1;
var DIFF_EQUAL = 0;

/** @typedef {{0: number, 1: string}} */
diff_match_patch.Diff;


/**
 * Find the differences between two texts.  Simplifies the problem by stripping
 * any common prefix or suffix off the texts before diffing.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @param {boolean=} opt_checklines Optional speedup flag. If present and false,
 *     then don't run a line-level diff first to identify the changed areas.
 *     Defaults to true, which does a faster, slightly less optimal diff.
 * @param {number} opt_deadline Optional time when the diff should be complete
 *     by.  Used internally for recursive calls.  Users should set DiffTimeout
 *     instead.
 * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
 */
diff_match_patch.prototype.diff_main = function(text1, text2, opt_checklines,
    opt_deadline) {
  // Set a deadline by which time the diff must be complete.
  if (typeof opt_deadline == 'undefined') {
    if (this.Diff_Timeout <= 0) {
      opt_deadline = Number.MAX_VALUE;
    } else {
      opt_deadline = (new Date).getTime() + this.Diff_Timeout * 1000;
    }
  }
  var deadline = opt_deadline;

  // Check for null inputs.
  if (text1 == null || text2 == null) {
    throw new Error('Null input. (diff_main)');
  }

  // Check for equality (speedup).
  if (text1 == text2) {
    if (text1) {
      return [[DIFF_EQUAL, text1]];
    }
    return [];
  }

  if (typeof opt_checklines == 'undefined') {
    opt_checklines = true;
  }
  var checklines = opt_checklines;

  // Trim off common prefix (speedup).
  var commonlength = this.diff_commonPrefix(text1, text2);
  var commonprefix = text1.substring(0, commonlength);
  text1 = text1.substring(commonlength);
  text2 = text2.substring(commonlength);

  // Trim off common suffix (speedup).
  commonlength = this.diff_commonSuffix(text1, text2);
  var commonsuffix = text1.substring(text1.length - commonlength);
  text1 = text1.substring(0, text1.length - commonlength);
  text2 = text2.substring(0, text2.length - commonlength);

  // Compute the diff on the middle block.
  var diffs = this.diff_compute_(text1, text2, checklines, deadline);

  // Restore the prefix and suffix.
  if (commonprefix) {
    diffs.unshift([DIFF_EQUAL, commonprefix]);
  }
  if (commonsuffix) {
    diffs.push([DIFF_EQUAL, commonsuffix]);
  }
  this.diff_cleanupMerge(diffs);
  return diffs;
};


/**
 * Find the differences between two texts.  Assumes that the texts do not
 * have any common prefix or suffix.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @param {boolean} checklines Speedup flag.  If false, then don't run a
 *     line-level diff first to identify the changed areas.
 *     If true, then run a faster, slightly less optimal diff.
 * @param {number} deadline Time when the diff should be complete by.
 * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
 * @private
 */
diff_match_patch.prototype.diff_compute_ = function(text1, text2, checklines,
    deadline) {
  var diffs;

  if (!text1) {
    // Just add some text (speedup).
    return [[DIFF_INSERT, text2]];
  }

  if (!text2) {
    // Just delete some text (speedup).
    return [[DIFF_DELETE, text1]];
  }

  var longtext = text1.length > text2.length ? text1 : text2;
  var shorttext = text1.length > text2.length ? text2 : text1;
  var i = longtext.indexOf(shorttext);
  if (i != -1) {
    // Shorter text is inside the longer text (speedup).
    diffs = [[DIFF_INSERT, longtext.substring(0, i)],
             [DIFF_EQUAL, shorttext],
             [DIFF_INSERT, longtext.substring(i + shorttext.length)]];
    // Swap insertions for deletions if diff is reversed.
    if (text1.length > text2.length) {
      diffs[0][0] = diffs[2][0] = DIFF_DELETE;
    }
    return diffs;
  }

  if (shorttext.length == 1) {
    // Single character string.
    // After the previous speedup, the character can't be an equality.
    return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
  }

  // Check to see if the problem can be split in two.
  var hm = this.diff_halfMatch_(text1, text2);
  if (hm) {
    // A half-match was found, sort out the return data.
    var text1_a = hm[0];
    var text1_b = hm[1];
    var text2_a = hm[2];
    var text2_b = hm[3];
    var mid_common = hm[4];
    // Send both pairs off for separate processing.
    var diffs_a = this.diff_main(text1_a, text2_a, checklines, deadline);
    var diffs_b = this.diff_main(text1_b, text2_b, checklines, deadline);
    // Merge the results.
    return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b);
  }

  if (checklines && text1.length > 100 && text2.length > 100) {
    return this.diff_lineMode_(text1, text2, deadline);
  }

  return this.diff_bisect_(text1, text2, deadline);
};


/**
 * Do a quick line-level diff on both strings, then rediff the parts for
 * greater accuracy.
 * This speedup can produce non-minimal diffs.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @param {number} deadline Time when the diff should be complete by.
 * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
 * @private
 */
diff_match_patch.prototype.diff_lineMode_ = function(text1, text2, deadline) {
  // Scan the text on a line-by-line basis first.
  var a = this.diff_linesToChars_(text1, text2);
  text1 = a.chars1;
  text2 = a.chars2;
  var linearray = a.lineArray;

  var diffs = this.diff_main(text1, text2, false, deadline);

  // Convert the diff back to original text.
  this.diff_charsToLines_(diffs, linearray);
  // Eliminate freak matches (e.g. blank lines)
  this.diff_cleanupSemantic(diffs);

  // Rediff any replacement blocks, this time character-by-character.
  // Add a dummy entry at the end.
  diffs.push([DIFF_EQUAL, '']);
  var pointer = 0;
  var count_delete = 0;
  var count_insert = 0;
  var text_delete = '';
  var text_insert = '';
  while (pointer < diffs.length) {
    switch (diffs[pointer][0]) {
      case DIFF_INSERT:
        count_insert++;
        text_insert += diffs[pointer][1];
        break;
      case DIFF_DELETE:
        count_delete++;
        text_delete += diffs[pointer][1];
        break;
      case DIFF_EQUAL:
        // Upon reaching an equality, check for prior redundancies.
        if (count_delete >= 1 && count_insert >= 1) {
          // Delete the offending records and add the merged ones.
          diffs.splice(pointer - count_delete - count_insert,
                       count_delete + count_insert);
          pointer = pointer - count_delete - count_insert;
          var a = this.diff_main(text_delete, text_insert, false, deadline);
          for (var j = a.length - 1; j >= 0; j--) {
            diffs.splice(pointer, 0, a[j]);
          }
          pointer = pointer + a.length;
        }
        count_insert = 0;
        count_delete = 0;
        text_delete = '';
        text_insert = '';
        break;
    }
    pointer++;
  }
  diffs.pop();  // Remove the dummy entry at the end.

  return diffs;
};


/**
 * Find the 'middle snake' of a diff, split the problem in two
 * and return the recursively constructed diff.
 * See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @param {number} deadline Time at which to bail if not yet complete.
 * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
 * @private
 */
diff_match_patch.prototype.diff_bisect_ = function(text1, text2, deadline) {
  // Cache the text lengths to prevent multiple calls.
  var text1_length = text1.length;
  var text2_length = text2.length;
  var max_d = Math.ceil((text1_length + text2_length) / 2);
  var v_offset = max_d;
  var v_length = 2 * max_d;
  var v1 = new Array(v_length);
  var v2 = new Array(v_length);
  // Setting all elements to -1 is faster in Chrome & Firefox than mixing
  // integers and undefined.
  for (var x = 0; x < v_length; x++) {
    v1[x] = -1;
    v2[x] = -1;
  }
  v1[v_offset + 1] = 0;
  v2[v_offset + 1] = 0;
  var delta = text1_length - text2_length;
  // If the total number of characters is odd, then the front path will collide
  // with the reverse path.
  var front = (delta % 2 != 0);
  // Offsets for start and end of k loop.
  // Prevents mapping of space beyond the grid.
  var k1start = 0;
  var k1end = 0;
  var k2start = 0;
  var k2end = 0;
  for (var d = 0; d < max_d; d++) {
    // Bail out if deadline is reached.
    if ((new Date()).getTime() > deadline) {
      break;
    }

    // Walk the front path one step.
    for (var k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
      var k1_offset = v_offset + k1;
      var x1;
      if (k1 == -d || (k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])) {
        x1 = v1[k1_offset + 1];
      } else {
        x1 = v1[k1_offset - 1] + 1;
      }
      var y1 = x1 - k1;
      while (x1 < text1_length && y1 < text2_length &&
             text1.charAt(x1) == text2.charAt(y1)) {
        x1++;
        y1++;
      }
      v1[k1_offset] = x1;
      if (x1 > text1_length) {
        // Ran off the right of the graph.
        k1end += 2;
      } else if (y1 > text2_length) {
        // Ran off the bottom of the graph.
        k1start += 2;
      } else if (front) {
        var k2_offset = v_offset + delta - k1;
        if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1) {
          // Mirror x2 onto top-left coordinate system.
          var x2 = text1_length - v2[k2_offset];
          if (x1 >= x2) {
            // Overlap detected.
            return this.diff_bisectSplit_(text1, text2, x1, y1, deadline);
          }
        }
      }
    }

    // Walk the reverse path one step.
    for (var k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
      var k2_offset = v_offset + k2;
      var x2;
      if (k2 == -d || (k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])) {
        x2 = v2[k2_offset + 1];
      } else {
        x2 = v2[k2_offset - 1] + 1;
      }
      var y2 = x2 - k2;
      while (x2 < text1_length && y2 < text2_length &&
             text1.charAt(text1_length - x2 - 1) ==
             text2.charAt(text2_length - y2 - 1)) {
        x2++;
        y2++;
      }
      v2[k2_offset] = x2;
      if (x2 > text1_length) {
        // Ran off the left of the graph.
        k2end += 2;
      } else if (y2 > text2_length) {
        // Ran off the top of the graph.
        k2start += 2;
      } else if (!front) {
        var k1_offset = v_offset + delta - k2;
        if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1) {
          var x1 = v1[k1_offset];
          var y1 = v_offset + x1 - k1_offset;
          // Mirror x2 onto top-left coordinate system.
          x2 = text1_length - x2;
          if (x1 >= x2) {
            // Overlap detected.
            return this.diff_bisectSplit_(text1, text2, x1, y1, deadline);
          }
        }
      }
    }
  }
  // Diff took too long and hit the deadline or
  // number of diffs equals number of characters, no commonality at all.
  return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
};


/**
 * Given the location of the 'middle snake', split the diff in two parts
 * and recurse.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @param {number} x Index of split point in text1.
 * @param {number} y Index of split point in text2.
 * @param {number} deadline Time at which to bail if not yet complete.
 * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
 * @private
 */
diff_match_patch.prototype.diff_bisectSplit_ = function(text1, text2, x, y,
    deadline) {
  var text1a = text1.substring(0, x);
  var text2a = text2.substring(0, y);
  var text1b = text1.substring(x);
  var text2b = text2.substring(y);

  // Compute both diffs serially.
  var diffs = this.diff_main(text1a, text2a, false, deadline);
  var diffsb = this.diff_main(text1b, text2b, false, deadline);

  return diffs.concat(diffsb);
};


/**
 * Split two texts into an array of strings.  Reduce the texts to a string of
 * hashes where each Unicode character represents one line.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {{chars1: string, chars2: string, lineArray: !Array.<string>}}
 *     An object containing the encoded text1, the encoded text2 and
 *     the array of unique strings.
 *     The zeroth element of the array of unique strings is intentionally blank.
 * @private
 */
diff_match_patch.prototype.diff_linesToChars_ = function(text1, text2) {
  var lineArray = [];  // e.g. lineArray[4] == 'Hello\n'
  var lineHash = {};   // e.g. lineHash['Hello\n'] == 4

  // '\x00' is a valid character, but various debuggers don't like it.
  // So we'll insert a junk entry to avoid generating a null character.
  lineArray[0] = '';

  /**
   * Split a text into an array of strings.  Reduce the texts to a string of
   * hashes where each Unicode character represents one line.
   * Modifies linearray and linehash through being a closure.
   * @param {string} text String to encode.
   * @return {string} Encoded string.
   * @private
   */
  function diff_linesToCharsMunge_(text) {
    var chars = '';
    // Walk the text, pulling out a substring for each line.
    // text.split('\n') would would temporarily double our memory footprint.
    // Modifying text would create many large strings to garbage collect.
    var lineStart = 0;
    var lineEnd = -1;
    // Keeping our own length variable is faster than looking it up.
    var lineArrayLength = lineArray.length;
    while (lineEnd < text.length - 1) {
      lineEnd = text.indexOf('\n', lineStart);
      if (lineEnd == -1) {
        lineEnd = text.length - 1;
      }
      var line = text.substring(lineStart, lineEnd + 1);
      lineStart = lineEnd + 1;

      if (lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) :
          (lineHash[line] !== undefined)) {
        chars += String.fromCharCode(lineHash[line]);
      } else {
        chars += String.fromCharCode(lineArrayLength);
        lineHash[line] = lineArrayLength;
        lineArray[lineArrayLength++] = line;
      }
    }
    return chars;
  }

  var chars1 = diff_linesToCharsMunge_(text1);
  var chars2 = diff_linesToCharsMunge_(text2);
  return {chars1: chars1, chars2: chars2, lineArray: lineArray};
};


/**
 * Rehydrate the text in a diff from a string of line hashes to real lines of
 * text.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 * @param {!Array.<string>} lineArray Array of unique strings.
 * @private
 */
diff_match_patch.prototype.diff_charsToLines_ = function(diffs, lineArray) {
  for (var x = 0; x < diffs.length; x++) {
    var chars = diffs[x][1];
    var text = [];
    for (var y = 0; y < chars.length; y++) {
      text[y] = lineArray[chars.charCodeAt(y)];
    }
    diffs[x][1] = text.join('');
  }
};


/**
 * Determine the common prefix of two strings.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {number} The number of characters common to the start of each
 *     string.
 */
diff_match_patch.prototype.diff_commonPrefix = function(text1, text2) {
  // Quick check for common null cases.
  if (!text1 || !text2 || text1.charAt(0) != text2.charAt(0)) {
    return 0;
  }
  // Binary search.
  // Performance analysis: http://neil.fraser.name/news/2007/10/09/
  var pointermin = 0;
  var pointermax = Math.min(text1.length, text2.length);
  var pointermid = pointermax;
  var pointerstart = 0;
  while (pointermin < pointermid) {
    if (text1.substring(pointerstart, pointermid) ==
        text2.substring(pointerstart, pointermid)) {
      pointermin = pointermid;
      pointerstart = pointermin;
    } else {
      pointermax = pointermid;
    }
    pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
  }
  return pointermid;
};


/**
 * Determine the common suffix of two strings.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {number} The number of characters common to the end of each string.
 */
diff_match_patch.prototype.diff_commonSuffix = function(text1, text2) {
  // Quick check for common null cases.
  if (!text1 || !text2 ||
      text1.charAt(text1.length - 1) != text2.charAt(text2.length - 1)) {
    return 0;
  }
  // Binary search.
  // Performance analysis: http://neil.fraser.name/news/2007/10/09/
  var pointermin = 0;
  var pointermax = Math.min(text1.length, text2.length);
  var pointermid = pointermax;
  var pointerend = 0;
  while (pointermin < pointermid) {
    if (text1.substring(text1.length - pointermid, text1.length - pointerend) ==
        text2.substring(text2.length - pointermid, text2.length - pointerend)) {
      pointermin = pointermid;
      pointerend = pointermin;
    } else {
      pointermax = pointermid;
    }
    pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
  }
  return pointermid;
};


/**
 * Determine if the suffix of one string is the prefix of another.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {number} The number of characters common to the end of the first
 *     string and the start of the second string.
 * @private
 */
diff_match_patch.prototype.diff_commonOverlap_ = function(text1, text2) {
  // Cache the text lengths to prevent multiple calls.
  var text1_length = text1.length;
  var text2_length = text2.length;
  // Eliminate the null case.
  if (text1_length == 0 || text2_length == 0) {
    return 0;
  }
  // Truncate the longer string.
  if (text1_length > text2_length) {
    text1 = text1.substring(text1_length - text2_length);
  } else if (text1_length < text2_length) {
    text2 = text2.substring(0, text1_length);
  }
  var text_length = Math.min(text1_length, text2_length);
  // Quick check for the worst case.
  if (text1 == text2) {
    return text_length;
  }

  // Start by looking for a single character match
  // and increase length until no match is found.
  // Performance analysis: http://neil.fraser.name/news/2010/11/04/
  var best = 0;
  var length = 1;
  while (true) {
    var pattern = text1.substring(text_length - length);
    var found = text2.indexOf(pattern);
    if (found == -1) {
      return best;
    }
    length += found;
    if (found == 0 || text1.substring(text_length - length) ==
        text2.substring(0, length)) {
      best = length;
      length++;
    }
  }
};


/**
 * Do the two texts share a substring which is at least half the length of the
 * longer text?
 * This speedup can produce non-minimal diffs.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {Array.<string>} Five element Array, containing the prefix of
 *     text1, the suffix of text1, the prefix of text2, the suffix of
 *     text2 and the common middle.  Or null if there was no match.
 * @private
 */
diff_match_patch.prototype.diff_halfMatch_ = function(text1, text2) {
  if (this.Diff_Timeout <= 0) {
    // Don't risk returning a non-optimal diff if we have unlimited time.
    return null;
  }
  var longtext = text1.length > text2.length ? text1 : text2;
  var shorttext = text1.length > text2.length ? text2 : text1;
  if (longtext.length < 4 || shorttext.length * 2 < longtext.length) {
    return null;  // Pointless.
  }
  var dmp = this;  // 'this' becomes 'window' in a closure.

  /**
   * Does a substring of shorttext exist within longtext such that the substring
   * is at least half the length of longtext?
   * Closure, but does not reference any external variables.
   * @param {string} longtext Longer string.
   * @param {string} shorttext Shorter string.
   * @param {number} i Start index of quarter length substring within longtext.
   * @return {Array.<string>} Five element Array, containing the prefix of
   *     longtext, the suffix of longtext, the prefix of shorttext, the suffix
   *     of shorttext and the common middle.  Or null if there was no match.
   * @private
   */
  function diff_halfMatchI_(longtext, shorttext, i) {
    // Start with a 1/4 length substring at position i as a seed.
    var seed = longtext.substring(i, i + Math.floor(longtext.length / 4));
    var j = -1;
    var best_common = '';
    var best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b;
    while ((j = shorttext.indexOf(seed, j + 1)) != -1) {
      var prefixLength = dmp.diff_commonPrefix(longtext.substring(i),
                                               shorttext.substring(j));
      var suffixLength = dmp.diff_commonSuffix(longtext.substring(0, i),
                                               shorttext.substring(0, j));
      if (best_common.length < suffixLength + prefixLength) {
        best_common = shorttext.substring(j - suffixLength, j) +
            shorttext.substring(j, j + prefixLength);
        best_longtext_a = longtext.substring(0, i - suffixLength);
        best_longtext_b = longtext.substring(i + prefixLength);
        best_shorttext_a = shorttext.substring(0, j - suffixLength);
        best_shorttext_b = shorttext.substring(j + prefixLength);
      }
    }
    if (best_common.length * 2 >= longtext.length) {
      return [best_longtext_a, best_longtext_b,
              best_shorttext_a, best_shorttext_b, best_common];
    } else {
      return null;
    }
  }

  // First check if the second quarter is the seed for a half-match.
  var hm1 = diff_halfMatchI_(longtext, shorttext,
                             Math.ceil(longtext.length / 4));
  // Check again based on the third quarter.
  var hm2 = diff_halfMatchI_(longtext, shorttext,
                             Math.ceil(longtext.length / 2));
  var hm;
  if (!hm1 && !hm2) {
    return null;
  } else if (!hm2) {
    hm = hm1;
  } else if (!hm1) {
    hm = hm2;
  } else {
    // Both matched.  Select the longest.
    hm = hm1[4].length > hm2[4].length ? hm1 : hm2;
  }

  // A half-match was found, sort out the return data.
  var text1_a, text1_b, text2_a, text2_b;
  if (text1.length > text2.length) {
    text1_a = hm[0];
    text1_b = hm[1];
    text2_a = hm[2];
    text2_b = hm[3];
  } else {
    text2_a = hm[0];
    text2_b = hm[1];
    text1_a = hm[2];
    text1_b = hm[3];
  }
  var mid_common = hm[4];
  return [text1_a, text1_b, text2_a, text2_b, mid_common];
};


/**
 * Reduce the number of edits by eliminating semantically trivial equalities.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 */
diff_match_patch.prototype.diff_cleanupSemantic = function(diffs) {
  var changes = false;
  var equalities = [];  // Stack of indices where equalities are found.
  var equalitiesLength = 0;  // Keeping our own length var is faster in JS.
  /** @type {?string} */
  var lastequality = null;
  // Always equal to diffs[equalities[equalitiesLength - 1]][1]
  var pointer = 0;  // Index of current position.
  // Number of characters that changed prior to the equality.
  var length_insertions1 = 0;
  var length_deletions1 = 0;
  // Number of characters that changed after the equality.
  var length_insertions2 = 0;
  var length_deletions2 = 0;
  while (pointer < diffs.length) {
    if (diffs[pointer][0] == DIFF_EQUAL) {  // Equality found.
      equalities[equalitiesLength++] = pointer;
      length_insertions1 = length_insertions2;
      length_deletions1 = length_deletions2;
      length_insertions2 = 0;
      length_deletions2 = 0;
      lastequality = diffs[pointer][1];
    } else {  // An insertion or deletion.
      if (diffs[pointer][0] == DIFF_INSERT) {
        length_insertions2 += diffs[pointer][1].length;
      } else {
        length_deletions2 += diffs[pointer][1].length;
      }
      // Eliminate an equality that is smaller or equal to the edits on both
      // sides of it.
      if (lastequality && (lastequality.length <=
          Math.max(length_insertions1, length_deletions1)) &&
          (lastequality.length <= Math.max(length_insertions2,
                                           length_deletions2))) {
        // Duplicate record.
        diffs.splice(equalities[equalitiesLength - 1], 0,
                     [DIFF_DELETE, lastequality]);
        // Change second copy to insert.
        diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT;
        // Throw away the equality we just deleted.
        equalitiesLength--;
        // Throw away the previous equality (it needs to be reevaluated).
        equalitiesLength--;
        pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -1;
        length_insertions1 = 0;  // Reset the counters.
        length_deletions1 = 0;
        length_insertions2 = 0;
        length_deletions2 = 0;
        lastequality = null;
        changes = true;
      }
    }
    pointer++;
  }

  // Normalize the diff.
  if (changes) {
    this.diff_cleanupMerge(diffs);
  }
  this.diff_cleanupSemanticLossless(diffs);

  // Find any overlaps between deletions and insertions.
  // e.g: <del>abcxxx</del><ins>xxxdef</ins>
  //   -> <del>abc</del>xxx<ins>def</ins>
  // e.g: <del>xxxabc</del><ins>defxxx</ins>
  //   -> <ins>def</ins>xxx<del>abc</del>
  // Only extract an overlap if it is as big as the edit ahead or behind it.
  pointer = 1;
  while (pointer < diffs.length) {
    if (diffs[pointer - 1][0] == DIFF_DELETE &&
        diffs[pointer][0] == DIFF_INSERT) {
      var deletion = diffs[pointer - 1][1];
      var insertion = diffs[pointer][1];
      var overlap_length1 = this.diff_commonOverlap_(deletion, insertion);
      var overlap_length2 = this.diff_commonOverlap_(insertion, deletion);
      if (overlap_length1 >= overlap_length2) {
        if (overlap_length1 >= deletion.length / 2 ||
            overlap_length1 >= insertion.length / 2) {
          // Overlap found.  Insert an equality and trim the surrounding edits.
          diffs.splice(pointer, 0,
              [DIFF_EQUAL, insertion.substring(0, overlap_length1)]);
          diffs[pointer - 1][1] =
              deletion.substring(0, deletion.length - overlap_length1);
          diffs[pointer + 1][1] = insertion.substring(overlap_length1);
          pointer++;
        }
      } else {
        if (overlap_length2 >= deletion.length / 2 ||
            overlap_length2 >= insertion.length / 2) {
          // Reverse overlap found.
          // Insert an equality and swap and trim the surrounding edits.
          diffs.splice(pointer, 0,
              [DIFF_EQUAL, deletion.substring(0, overlap_length2)]);
          diffs[pointer - 1][0] = DIFF_INSERT;
          diffs[pointer - 1][1] =
              insertion.substring(0, insertion.length - overlap_length2);
          diffs[pointer + 1][0] = DIFF_DELETE;
          diffs[pointer + 1][1] =
              deletion.substring(overlap_length2);
          pointer++;
        }
      }
      pointer++;
    }
    pointer++;
  }
};


/**
 * Look for single edits surrounded on both sides by equalities
 * which can be shifted sideways to align the edit to a word boundary.
 * e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 */
diff_match_patch.prototype.diff_cleanupSemanticLossless = function(diffs) {
  /**
   * Given two strings, compute a score representing whether the internal
   * boundary falls on logical boundaries.
   * Scores range from 6 (best) to 0 (worst).
   * Closure, but does not reference any external variables.
   * @param {string} one First string.
   * @param {string} two Second string.
   * @return {number} The score.
   * @private
   */
  function diff_cleanupSemanticScore_(one, two) {
    if (!one || !two) {
      // Edges are the best.
      return 6;
    }

    // Each port of this function behaves slightly differently due to
    // subtle differences in each language's definition of things like
    // 'whitespace'.  Since this function's purpose is largely cosmetic,
    // the choice has been made to use each language's native features
    // rather than force total conformity.
    var char1 = one.charAt(one.length - 1);
    var char2 = two.charAt(0);
    var nonAlphaNumeric1 = char1.match(diff_match_patch.nonAlphaNumericRegex_);
    var nonAlphaNumeric2 = char2.match(diff_match_patch.nonAlphaNumericRegex_);
    var whitespace1 = nonAlphaNumeric1 &&
        char1.match(diff_match_patch.whitespaceRegex_);
    var whitespace2 = nonAlphaNumeric2 &&
        char2.match(diff_match_patch.whitespaceRegex_);
    var lineBreak1 = whitespace1 &&
        char1.match(diff_match_patch.linebreakRegex_);
    var lineBreak2 = whitespace2 &&
        char2.match(diff_match_patch.linebreakRegex_);
    var blankLine1 = lineBreak1 &&
        one.match(diff_match_patch.blanklineEndRegex_);
    var blankLine2 = lineBreak2 &&
        two.match(diff_match_patch.blanklineStartRegex_);

    if (blankLine1 || blankLine2) {
      // Five points for blank lines.
      return 5;
    } else if (lineBreak1 || lineBreak2) {
      // Four points for line breaks.
      return 4;
    } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) {
      // Three points for end of sentences.
      return 3;
    } else if (whitespace1 || whitespace2) {
      // Two points for whitespace.
      return 2;
    } else if (nonAlphaNumeric1 || nonAlphaNumeric2) {
      // One point for non-alphanumeric.
      return 1;
    }
    return 0;
  }

  var pointer = 1;
  // Intentionally ignore the first and last element (don't need checking).
  while (pointer < diffs.length - 1) {
    if (diffs[pointer - 1][0] == DIFF_EQUAL &&
        diffs[pointer + 1][0] == DIFF_EQUAL) {
      // This is a single edit surrounded by equalities.
      var equality1 = diffs[pointer - 1][1];
      var edit = diffs[pointer][1];
      var equality2 = diffs[pointer + 1][1];

      // First, shift the edit as far left as possible.
      var commonOffset = this.diff_commonSuffix(equality1, edit);
      if (commonOffset) {
        var commonString = edit.substring(edit.length - commonOffset);
        equality1 = equality1.substring(0, equality1.length - commonOffset);
        edit = commonString + edit.substring(0, edit.length - commonOffset);
        equality2 = commonString + equality2;
      }

      // Second, step character by character right, looking for the best fit.
      var bestEquality1 = equality1;
      var bestEdit = edit;
      var bestEquality2 = equality2;
      var bestScore = diff_cleanupSemanticScore_(equality1, edit) +
          diff_cleanupSemanticScore_(edit, equality2);
      while (edit.charAt(0) === equality2.charAt(0)) {
        equality1 += edit.charAt(0);
        edit = edit.substring(1) + equality2.charAt(0);
        equality2 = equality2.substring(1);
        var score = diff_cleanupSemanticScore_(equality1, edit) +
            diff_cleanupSemanticScore_(edit, equality2);
        // The >= encourages trailing rather than leading whitespace on edits.
        if (score >= bestScore) {
          bestScore = score;
          bestEquality1 = equality1;
          bestEdit = edit;
          bestEquality2 = equality2;
        }
      }

      if (diffs[pointer - 1][1] != bestEquality1) {
        // We have an improvement, save it back to the diff.
        if (bestEquality1) {
          diffs[pointer - 1][1] = bestEquality1;
        } else {
          diffs.splice(pointer - 1, 1);
          pointer--;
        }
        diffs[pointer][1] = bestEdit;
        if (bestEquality2) {
          diffs[pointer + 1][1] = bestEquality2;
        } else {
          diffs.splice(pointer + 1, 1);
          pointer--;
        }
      }
    }
    pointer++;
  }
};

// Define some regex patterns for matching boundaries.
diff_match_patch.nonAlphaNumericRegex_ = /[^a-zA-Z0-9]/;
diff_match_patch.whitespaceRegex_ = /\s/;
diff_match_patch.linebreakRegex_ = /[\r\n]/;
diff_match_patch.blanklineEndRegex_ = /\n\r?\n$/;
diff_match_patch.blanklineStartRegex_ = /^\r?\n\r?\n/;

/**
 * Reduce the number of edits by eliminating operationally trivial equalities.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 */
diff_match_patch.prototype.diff_cleanupEfficiency = function(diffs) {
  var changes = false;
  var equalities = [];  // Stack of indices where equalities are found.
  var equalitiesLength = 0;  // Keeping our own length var is faster in JS.
  /** @type {?string} */
  var lastequality = null;
  // Always equal to diffs[equalities[equalitiesLength - 1]][1]
  var pointer = 0;  // Index of current position.
  // Is there an insertion operation before the last equality.
  var pre_ins = false;
  // Is there a deletion operation before the last equality.
  var pre_del = false;
  // Is there an insertion operation after the last equality.
  var post_ins = false;
  // Is there a deletion operation after the last equality.
  var post_del = false;
  while (pointer < diffs.length) {
    if (diffs[pointer][0] == DIFF_EQUAL) {  // Equality found.
      if (diffs[pointer][1].length < this.Diff_EditCost &&
          (post_ins || post_del)) {
        // Candidate found.
        equalities[equalitiesLength++] = pointer;
        pre_ins = post_ins;
        pre_del = post_del;
        lastequality = diffs[pointer][1];
      } else {
        // Not a candidate, and can never become one.
        equalitiesLength = 0;
        lastequality = null;
      }
      post_ins = post_del = false;
    } else {  // An insertion or deletion.
      if (diffs[pointer][0] == DIFF_DELETE) {
        post_del = true;
      } else {
        post_ins = true;
      }
      /*
       * Five types to be split:
       * <ins>A</ins><del>B</del>XY<ins>C</ins><del>D</del>
       * <ins>A</ins>X<ins>C</ins><del>D</del>
       * <ins>A</ins><del>B</del>X<ins>C</ins>
       * <ins>A</del>X<ins>C</ins><del>D</del>
       * <ins>A</ins><del>B</del>X<del>C</del>
       */
      if (lastequality && ((pre_ins && pre_del && post_ins && post_del) ||
                           ((lastequality.length < this.Diff_EditCost / 2) &&
                            (pre_ins + pre_del + post_ins + post_del) == 3))) {
        // Duplicate record.
        diffs.splice(equalities[equalitiesLength - 1], 0,
                     [DIFF_DELETE, lastequality]);
        // Change second copy to insert.
        diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT;
        equalitiesLength--;  // Throw away the equality we just deleted;
        lastequality = null;
        if (pre_ins && pre_del) {
          // No changes made which could affect previous entry, keep going.
          post_ins = post_del = true;
          equalitiesLength = 0;
        } else {
          equalitiesLength--;  // Throw away the previous equality.
          pointer = equalitiesLength > 0 ?
              equalities[equalitiesLength - 1] : -1;
          post_ins = post_del = false;
        }
        changes = true;
      }
    }
    pointer++;
  }

  if (changes) {
    this.diff_cleanupMerge(diffs);
  }
};


/**
 * Reorder and merge like edit sections.  Merge equalities.
 * Any edit section can move as long as it doesn't cross an equality.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 */
diff_match_patch.prototype.diff_cleanupMerge = function(diffs) {
  diffs.push([DIFF_EQUAL, '']);  // Add a dummy entry at the end.
  var pointer = 0;
  var count_delete = 0;
  var count_insert = 0;
  var text_delete = '';
  var text_insert = '';
  var commonlength;
  while (pointer < diffs.length) {
    switch (diffs[pointer][0]) {
      case DIFF_INSERT:
        count_insert++;
        text_insert += diffs[pointer][1];
        pointer++;
        break;
      case DIFF_DELETE:
        count_delete++;
        text_delete += diffs[pointer][1];
        pointer++;
        break;
      case DIFF_EQUAL:
        // Upon reaching an equality, check for prior redundancies.
        if (count_delete + count_insert > 1) {
          if (count_delete !== 0 && count_insert !== 0) {
            // Factor out any common prefixies.
            commonlength = this.diff_commonPrefix(text_insert, text_delete);
            if (commonlength !== 0) {
              if ((pointer - count_delete - count_insert) > 0 &&
                  diffs[pointer - count_delete - count_insert - 1][0] ==
                  DIFF_EQUAL) {
                diffs[pointer - count_delete - count_insert - 1][1] +=
                    text_insert.substring(0, commonlength);
              } else {
                diffs.splice(0, 0, [DIFF_EQUAL,
                                    text_insert.substring(0, commonlength)]);
                pointer++;
              }
              text_insert = text_insert.substring(commonlength);
              text_delete = text_delete.substring(commonlength);
            }
            // Factor out any common suffixies.
            commonlength = this.diff_commonSuffix(text_insert, text_delete);
            if (commonlength !== 0) {
              diffs[pointer][1] = text_insert.substring(text_insert.length -
                  commonlength) + diffs[pointer][1];
              text_insert = text_insert.substring(0, text_insert.length -
                  commonlength);
              text_delete = text_delete.substring(0, text_delete.length -
                  commonlength);
            }
          }
          // Delete the offending records and add the merged ones.
          if (count_delete === 0) {
            diffs.splice(pointer - count_insert,
                count_delete + count_insert, [DIFF_INSERT, text_insert]);
          } else if (count_insert === 0) {
            diffs.splice(pointer - count_delete,
                count_delete + count_insert, [DIFF_DELETE, text_delete]);
          } else {
            diffs.splice(pointer - count_delete - count_insert,
                count_delete + count_insert, [DIFF_DELETE, text_delete],
                [DIFF_INSERT, text_insert]);
          }
          pointer = pointer - count_delete - count_insert +
                    (count_delete ? 1 : 0) + (count_insert ? 1 : 0) + 1;
        } else if (pointer !== 0 && diffs[pointer - 1][0] == DIFF_EQUAL) {
          // Merge this equality with the previous one.
          diffs[pointer - 1][1] += diffs[pointer][1];
          diffs.splice(pointer, 1);
        } else {
          pointer++;
        }
        count_insert = 0;
        count_delete = 0;
        text_delete = '';
        text_insert = '';
        break;
    }
  }
  if (diffs[diffs.length - 1][1] === '') {
    diffs.pop();  // Remove the dummy entry at the end.
  }

  // Second pass: look for single edits surrounded on both sides by equalities
  // which can be shifted sideways to eliminate an equality.
  // e.g: A<ins>BA</ins>C -> <ins>AB</ins>AC
  var changes = false;
  pointer = 1;
  // Intentionally ignore the first and last element (don't need checking).
  while (pointer < diffs.length - 1) {
    if (diffs[pointer - 1][0] == DIFF_EQUAL &&
        diffs[pointer + 1][0] == DIFF_EQUAL) {
      // This is a single edit surrounded by equalities.
      if (diffs[pointer][1].substring(diffs[pointer][1].length -
          diffs[pointer - 1][1].length) == diffs[pointer - 1][1]) {
        // Shift the edit over the previous equality.
        diffs[pointer][1] = diffs[pointer - 1][1] +
            diffs[pointer][1].substring(0, diffs[pointer][1].length -
                                        diffs[pointer - 1][1].length);
        diffs[pointer + 1][1] = diffs[pointer - 1][1] + diffs[pointer + 1][1];
        diffs.splice(pointer - 1, 1);
        changes = true;
      } else if (diffs[pointer][1].substring(0, diffs[pointer + 1][1].length) ==
          diffs[pointer + 1][1]) {
        // Shift the edit over the next equality.
        diffs[pointer - 1][1] += diffs[pointer + 1][1];
        diffs[pointer][1] =
            diffs[pointer][1].substring(diffs[pointer + 1][1].length) +
            diffs[pointer + 1][1];
        diffs.splice(pointer + 1, 1);
        changes = true;
      }
    }
    pointer++;
  }
  // If shifts were made, the diff needs reordering and another shift sweep.
  if (changes) {
    this.diff_cleanupMerge(diffs);
  }
};


/**
 * loc is a location in text1, compute and return the equivalent location in
 * text2.
 * e.g. 'The cat' vs 'The big cat', 1->1, 5->8
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 * @param {number} loc Location within text1.
 * @return {number} Location within text2.
 */
diff_match_patch.prototype.diff_xIndex = function(diffs, loc) {
  var chars1 = 0;
  var chars2 = 0;
  var last_chars1 = 0;
  var last_chars2 = 0;
  var x;
  for (x = 0; x < diffs.length; x++) {
    if (diffs[x][0] !== DIFF_INSERT) {  // Equality or deletion.
      chars1 += diffs[x][1].length;
    }
    if (diffs[x][0] !== DIFF_DELETE) {  // Equality or insertion.
      chars2 += diffs[x][1].length;
    }
    if (chars1 > loc) {  // Overshot the location.
      break;
    }
    last_chars1 = chars1;
    last_chars2 = chars2;
  }
  // Was the location was deleted?
  if (diffs.length != x && diffs[x][0] === DIFF_DELETE) {
    return last_chars2;
  }
  // Add the remaining character length.
  return last_chars2 + (loc - last_chars1);
};


/**
 * Convert a diff array into a pretty HTML report.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 * @return {string} HTML representation.
 */
diff_match_patch.prototype.diff_prettyHtml = function(diffs) {
  var html = [];
  var pattern_amp = /&/g;
  var pattern_lt = /</g;
  var pattern_gt = />/g;
  var pattern_para = /\n/g;
  for (var x = 0; x < diffs.length; x++) {
    var op = diffs[x][0];    // Operation (insert, delete, equal)
    var data = diffs[x][1];  // Text of change.
    var text = data.replace(pattern_amp, '&amp;').replace(pattern_lt, '&lt;')
        .replace(pattern_gt, '&gt;').replace(pattern_para, '&para;<br>');
    switch (op) {
      case DIFF_INSERT:
        html[x] = '<ins style="background:#e6ffe6;">' + text + '</ins>';
        break;
      case DIFF_DELETE:
        html[x] = '<del style="background:#ffe6e6;">' + text + '</del>';
        break;
      case DIFF_EQUAL:
        html[x] = '<span>' + text + '</span>';
        break;
    }
  }
  return html.join('');
};


/**
 * Compute and return the source text (all equalities and deletions).
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 * @return {string} Source text.
 */
diff_match_patch.prototype.diff_text1 = function(diffs) {
  var text = [];
  for (var x = 0; x < diffs.length; x++) {
    if (diffs[x][0] !== DIFF_INSERT) {
      text[x] = diffs[x][1];
    }
  }
  return text.join('');
};


/**
 * Compute and return the destination text (all equalities and insertions).
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 * @return {string} Destination text.
 */
diff_match_patch.prototype.diff_text2 = function(diffs) {
  var text = [];
  for (var x = 0; x < diffs.length; x++) {
    if (diffs[x][0] !== DIFF_DELETE) {
      text[x] = diffs[x][1];
    }
  }
  return text.join('');
};


/**
 * Compute the Levenshtein distance; the number of inserted, deleted or
 * substituted characters.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 * @return {number} Number of changes.
 */
diff_match_patch.prototype.diff_levenshtein = function(diffs) {
  var levenshtein = 0;
  var insertions = 0;
  var deletions = 0;
  for (var x = 0; x < diffs.length; x++) {
    var op = diffs[x][0];
    var data = diffs[x][1];
    switch (op) {
      case DIFF_INSERT:
        insertions += data.length;
        break;
      case DIFF_DELETE:
        deletions += data.length;
        break;
      case DIFF_EQUAL:
        // A deletion and an insertion is one substitution.
        levenshtein += Math.max(insertions, deletions);
        insertions = 0;
        deletions = 0;
        break;
    }
  }
  levenshtein += Math.max(insertions, deletions);
  return levenshtein;
};


/**
 * Crush the diff into an encoded string which describes the operations
 * required to transform text1 into text2.
 * E.g. =3\t-2\t+ing  -> Keep 3 chars, delete 2 chars, insert 'ing'.
 * Operations are tab-separated.  Inserted text is escaped using %xx notation.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 * @return {string} Delta text.
 */
diff_match_patch.prototype.diff_toDelta = function(diffs) {
  var text = [];
  for (var x = 0; x < diffs.length; x++) {
    switch (diffs[x][0]) {
      case DIFF_INSERT:
        text[x] = '+' + encodeURI(diffs[x][1]);
        break;
      case DIFF_DELETE:
        text[x] = '-' + diffs[x][1].length;
        break;
      case DIFF_EQUAL:
        text[x] = '=' + diffs[x][1].length;
        break;
    }
  }
  return text.join('\t').replace(/%20/g, ' ');
};


/**
 * Given the original text1, and an encoded string which describes the
 * operations required to transform text1 into text2, compute the full diff.
 * @param {string} text1 Source string for the diff.
 * @param {string} delta Delta text.
 * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
 * @throws {!Error} If invalid input.
 */
diff_match_patch.prototype.diff_fromDelta = function(text1, delta) {
  var diffs = [];
  var diffsLength = 0;  // Keeping our own length var is faster in JS.
  var pointer = 0;  // Cursor in text1
  var tokens = delta.split(/\t/g);
  for (var x = 0; x < tokens.length; x++) {
    // Each token begins with a one character parameter which specifies the
    // operation of this token (delete, insert, equality).
    var param = tokens[x].substring(1);
    switch (tokens[x].charAt(0)) {
      case '+':
        try {
          diffs[diffsLength++] = [DIFF_INSERT, decodeURI(param)];
        } catch (ex) {
          // Malformed URI sequence.
          throw new Error('Illegal escape in diff_fromDelta: ' + param);
        }
        break;
      case '-':
        // Fall through.
      case '=':
        var n = parseInt(param, 10);
        if (isNaN(n) || n < 0) {
          throw new Error('Invalid number in diff_fromDelta: ' + param);
        }
        var text = text1.substring(pointer, pointer += n);
        if (tokens[x].charAt(0) == '=') {
          diffs[diffsLength++] = [DIFF_EQUAL, text];
        } else {
          diffs[diffsLength++] = [DIFF_DELETE, text];
        }
        break;
      default:
        // Blank tokens are ok (from a trailing \t).
        // Anything else is an error.
        if (tokens[x]) {
          throw new Error('Invalid diff operation in diff_fromDelta: ' +
                          tokens[x]);
        }
    }
  }
  if (pointer != text1.length) {
    throw new Error('Delta length (' + pointer +
        ') does not equal source text length (' + text1.length + ').');
  }
  return diffs;
};


//  MATCH FUNCTIONS


/**
 * Locate the best instance of 'pattern' in 'text' near 'loc'.
 * @param {string} text The text to search.
 * @param {string} pattern The pattern to search for.
 * @param {number} loc The location to search around.
 * @return {number} Best match index or -1.
 */
diff_match_patch.prototype.match_main = function(text, pattern, loc) {
  // Check for null inputs.
  if (text == null || pattern == null || loc == null) {
    throw new Error('Null input. (match_main)');
  }

  loc = Math.max(0, Math.min(loc, text.length));
  if (text == pattern) {
    // Shortcut (potentially not guaranteed by the algorithm)
    return 0;
  } else if (!text.length) {
    // Nothing to match.
    return -1;
  } else if (text.substring(loc, loc + pattern.length) == pattern) {
    // Perfect match at the perfect spot!  (Includes case of null pattern)
    return loc;
  } else {
    // Do a fuzzy compare.
    return this.match_bitap_(text, pattern, loc);
  }
};


/**
 * Locate the best instance of 'pattern' in 'text' near 'loc' using the
 * Bitap algorithm.
 * @param {string} text The text to search.
 * @param {string} pattern The pattern to search for.
 * @param {number} loc The location to search around.
 * @return {number} Best match index or -1.
 * @private
 */
diff_match_patch.prototype.match_bitap_ = function(text, pattern, loc) {
  if (pattern.length > this.Match_MaxBits) {
    throw new Error('Pattern too long for this browser.');
  }

  // Initialise the alphabet.
  var s = this.match_alphabet_(pattern);

  var dmp = this;  // 'this' becomes 'window' in a closure.

  /**
   * Compute and return the score for a match with e errors and x location.
   * Accesses loc and pattern through being a closure.
   * @param {number} e Number of errors in match.
   * @param {number} x Location of match.
   * @return {number} Overall score for match (0.0 = good, 1.0 = bad).
   * @private
   */
  function match_bitapScore_(e, x) {
    var accuracy = e / pattern.length;
    var proximity = Math.abs(loc - x);
    if (!dmp.Match_Distance) {
      // Dodge divide by zero error.
      return proximity ? 1.0 : accuracy;
    }
    return accuracy + (proximity / dmp.Match_Distance);
  }

  // Highest score beyond which we give up.
  var score_threshold = this.Match_Threshold;
  // Is there a nearby exact match? (speedup)
  var best_loc = text.indexOf(pattern, loc);
  if (best_loc != -1) {
    score_threshold = Math.min(match_bitapScore_(0, best_loc), score_threshold);
    // What about in the other direction? (speedup)
    best_loc = text.lastIndexOf(pattern, loc + pattern.length);
    if (best_loc != -1) {
      score_threshold =
          Math.min(match_bitapScore_(0, best_loc), score_threshold);
    }
  }

  // Initialise the bit arrays.
  var matchmask = 1 << (pattern.length - 1);
  best_loc = -1;

  var bin_min, bin_mid;
  var bin_max = pattern.length + text.length;
  var last_rd;
  for (var d = 0; d < pattern.length; d++) {
    // Scan for the best match; each iteration allows for one more error.
    // Run a binary search to determine how far from 'loc' we can stray at this
    // error level.
    bin_min = 0;
    bin_mid = bin_max;
    while (bin_min < bin_mid) {
      if (match_bitapScore_(d, loc + bin_mid) <= score_threshold) {
        bin_min = bin_mid;
      } else {
        bin_max = bin_mid;
      }
      bin_mid = Math.floor((bin_max - bin_min) / 2 + bin_min);
    }
    // Use the result from this iteration as the maximum for the next.
    bin_max = bin_mid;
    var start = Math.max(1, loc - bin_mid + 1);
    var finish = Math.min(loc + bin_mid, text.length) + pattern.length;

    var rd = Array(finish + 2);
    rd[finish + 1] = (1 << d) - 1;
    for (var j = finish; j >= start; j--) {
      // The alphabet (s) is a sparse hash, so the following line generates
      // warnings.
      var charMatch = s[text.charAt(j - 1)];
      if (d === 0) {  // First pass: exact match.
        rd[j] = ((rd[j + 1] << 1) | 1) & charMatch;
      } else {  // Subsequent passes: fuzzy match.
        rd[j] = (((rd[j + 1] << 1) | 1) & charMatch) |
                (((last_rd[j + 1] | last_rd[j]) << 1) | 1) |
                last_rd[j + 1];
      }
      if (rd[j] & matchmask) {
        var score = match_bitapScore_(d, j - 1);
        // This match will almost certainly be better than any existing match.
        // But check anyway.
        if (score <= score_threshold) {
          // Told you so.
          score_threshold = score;
          best_loc = j - 1;
          if (best_loc > loc) {
            // When passing loc, don't exceed our current distance from loc.
            start = Math.max(1, 2 * loc - best_loc);
          } else {
            // Already passed loc, downhill from here on in.
            break;
          }
        }
      }
    }
    // No hope for a (better) match at greater error levels.
    if (match_bitapScore_(d + 1, loc) > score_threshold) {
      break;
    }
    last_rd = rd;
  }
  return best_loc;
};


/**
 * Initialise the alphabet for the Bitap algorithm.
 * @param {string} pattern The text to encode.
 * @return {!Object} Hash of character locations.
 * @private
 */
diff_match_patch.prototype.match_alphabet_ = function(pattern) {
  var s = {};
  for (var i = 0; i < pattern.length; i++) {
    s[pattern.charAt(i)] = 0;
  }
  for (var i = 0; i < pattern.length; i++) {
    s[pattern.charAt(i)] |= 1 << (pattern.length - i - 1);
  }
  return s;
};


//  PATCH FUNCTIONS


/**
 * Increase the context until it is unique,
 * but don't let the pattern expand beyond Match_MaxBits.
 * @param {!diff_match_patch.patch_obj} patch The patch to grow.
 * @param {string} text Source text.
 * @private
 */
diff_match_patch.prototype.patch_addContext_ = function(patch, text) {
  if (text.length == 0) {
    return;
  }
  var pattern = text.substring(patch.start2, patch.start2 + patch.length1);
  var padding = 0;

  // Look for the first and last matches of pattern in text.  If two different
  // matches are found, increase the pattern length.
  while (text.indexOf(pattern) != text.lastIndexOf(pattern) &&
         pattern.length < this.Match_MaxBits - this.Patch_Margin -
         this.Patch_Margin) {
    padding += this.Patch_Margin;
    pattern = text.substring(patch.start2 - padding,
                             patch.start2 + patch.length1 + padding);
  }
  // Add one chunk for good luck.
  padding += this.Patch_Margin;

  // Add the prefix.
  var prefix = text.substring(patch.start2 - padding, patch.start2);
  if (prefix) {
    patch.diffs.unshift([DIFF_EQUAL, prefix]);
  }
  // Add the suffix.
  var suffix = text.substring(patch.start2 + patch.length1,
                              patch.start2 + patch.length1 + padding);
  if (suffix) {
    patch.diffs.push([DIFF_EQUAL, suffix]);
  }

  // Roll back the start points.
  patch.start1 -= prefix.length;
  patch.start2 -= prefix.length;
  // Extend the lengths.
  patch.length1 += prefix.length + suffix.length;
  patch.length2 += prefix.length + suffix.length;
};


/**
 * Compute a list of patches to turn text1 into text2.
 * Use diffs if provided, otherwise compute it ourselves.
 * There are four ways to call this function, depending on what data is
 * available to the caller:
 * Method 1:
 * a = text1, b = text2
 * Method 2:
 * a = diffs
 * Method 3 (optimal):
 * a = text1, b = diffs
 * Method 4 (deprecated, use method 3):
 * a = text1, b = text2, c = diffs
 *
 * @param {string|!Array.<!diff_match_patch.Diff>} a text1 (methods 1,3,4) or
 * Array of diff tuples for text1 to text2 (method 2).
 * @param {string|!Array.<!diff_match_patch.Diff>} opt_b text2 (methods 1,4) or
 * Array of diff tuples for text1 to text2 (method 3) or undefined (method 2).
 * @param {string|!Array.<!diff_match_patch.Diff>} opt_c Array of diff tuples
 * for text1 to text2 (method 4) or undefined (methods 1,2,3).
 * @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects.
 */
diff_match_patch.prototype.patch_make = function(a, opt_b, opt_c) {
  var text1, diffs;
  if (typeof a == 'string' && typeof opt_b == 'string' &&
      typeof opt_c == 'undefined') {
    // Method 1: text1, text2
    // Compute diffs from text1 and text2.
    text1 = /** @type {string} */(a);
    diffs = this.diff_main(text1, /** @type {string} */(opt_b), true);
    if (diffs.length > 2) {
      this.diff_cleanupSemantic(diffs);
      this.diff_cleanupEfficiency(diffs);
    }
  } else if (a && typeof a == 'object' && typeof opt_b == 'undefined' &&
      typeof opt_c == 'undefined') {
    // Method 2: diffs
    // Compute text1 from diffs.
    diffs = /** @type {!Array.<!diff_match_patch.Diff>} */(a);
    text1 = this.diff_text1(diffs);
  } else if (typeof a == 'string' && opt_b && typeof opt_b == 'object' &&
      typeof opt_c == 'undefined') {
    // Method 3: text1, diffs
    text1 = /** @type {string} */(a);
    diffs = /** @type {!Array.<!diff_match_patch.Diff>} */(opt_b);
  } else if (typeof a == 'string' && typeof opt_b == 'string' &&
      opt_c && typeof opt_c == 'object') {
    // Method 4: text1, text2, diffs
    // text2 is not used.
    text1 = /** @type {string} */(a);
    diffs = /** @type {!Array.<!diff_match_patch.Diff>} */(opt_c);
  } else {
    throw new Error('Unknown call format to patch_make.');
  }

  if (diffs.length === 0) {
    return [];  // Get rid of the null case.
  }
  var patches = [];
  var patch = new diff_match_patch.patch_obj();
  var patchDiffLength = 0;  // Keeping our own length var is faster in JS.
  var char_count1 = 0;  // Number of characters into the text1 string.
  var char_count2 = 0;  // Number of characters into the text2 string.
  // Start with text1 (prepatch_text) and apply the diffs until we arrive at
  // text2 (postpatch_text).  We recreate the patches one by one to determine
  // context info.
  var prepatch_text = text1;
  var postpatch_text = text1;
  for (var x = 0; x < diffs.length; x++) {
    var diff_type = diffs[x][0];
    var diff_text = diffs[x][1];

    if (!patchDiffLength && diff_type !== DIFF_EQUAL) {
      // A new patch starts here.
      patch.start1 = char_count1;
      patch.start2 = char_count2;
    }

    switch (diff_type) {
      case DIFF_INSERT:
        patch.diffs[patchDiffLength++] = diffs[x];
        patch.length2 += diff_text.length;
        postpatch_text = postpatch_text.substring(0, char_count2) + diff_text +
                         postpatch_text.substring(char_count2);
        break;
      case DIFF_DELETE:
        patch.length1 += diff_text.length;
        patch.diffs[patchDiffLength++] = diffs[x];
        postpatch_text = postpatch_text.substring(0, char_count2) +
                         postpatch_text.substring(char_count2 +
                             diff_text.length);
        break;
      case DIFF_EQUAL:
        if (diff_text.length <= 2 * this.Patch_Margin &&
            patchDiffLength && diffs.length != x + 1) {
          // Small equality inside a patch.
          patch.diffs[patchDiffLength++] = diffs[x];
          patch.length1 += diff_text.length;
          patch.length2 += diff_text.length;
        } else if (diff_text.length >= 2 * this.Patch_Margin) {
          // Time for a new patch.
          if (patchDiffLength) {
            this.patch_addContext_(patch, prepatch_text);
            patches.push(patch);
            patch = new diff_match_patch.patch_obj();
            patchDiffLength = 0;
            // Unlike Unidiff, our patch lists have a rolling context.
            // http://code.google.com/p/google-diff-match-patch/wiki/Unidiff
            // Update prepatch text & pos to reflect the application of the
            // just completed patch.
            prepatch_text = postpatch_text;
            char_count1 = char_count2;
          }
        }
        break;
    }

    // Update the current character count.
    if (diff_type !== DIFF_INSERT) {
      char_count1 += diff_text.length;
    }
    if (diff_type !== DIFF_DELETE) {
      char_count2 += diff_text.length;
    }
  }
  // Pick up the leftover patch if not empty.
  if (patchDiffLength) {
    this.patch_addContext_(patch, prepatch_text);
    patches.push(patch);
  }

  return patches;
};


/**
 * Given an array of patches, return another array that is identical.
 * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
 * @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects.
 */
diff_match_patch.prototype.patch_deepCopy = function(patches) {
  // Making deep copies is hard in JavaScript.
  var patchesCopy = [];
  for (var x = 0; x < patches.length; x++) {
    var patch = patches[x];
    var patchCopy = new diff_match_patch.patch_obj();
    patchCopy.diffs = [];
    for (var y = 0; y < patch.diffs.length; y++) {
      patchCopy.diffs[y] = patch.diffs[y].slice();
    }
    patchCopy.start1 = patch.start1;
    patchCopy.start2 = patch.start2;
    patchCopy.length1 = patch.length1;
    patchCopy.length2 = patch.length2;
    patchesCopy[x] = patchCopy;
  }
  return patchesCopy;
};


/**
 * Merge a set of patches onto the text.  Return a patched text, as well
 * as a list of true/false values indicating which patches were applied.
 * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
 * @param {string} text Old text.
 * @return {!Array.<string|!Array.<boolean>>} Two element Array, containing the
 *      new text and an array of boolean values.
 */
diff_match_patch.prototype.patch_apply = function(patches, text) {
  if (patches.length == 0) {
    return [text, []];
  }

  // Deep copy the patches so that no changes are made to originals.
  patches = this.patch_deepCopy(patches);

  var nullPadding = this.patch_addPadding(patches);
  text = nullPadding + text + nullPadding;

  this.patch_splitMax(patches);
  // delta keeps track of the offset between the expected and actual location
  // of the previous patch.  If there are patches expected at positions 10 and
  // 20, but the first patch was found at 12, delta is 2 and the second patch
  // has an effective expected position of 22.
  var delta = 0;
  var results = [];
  for (var x = 0; x < patches.length; x++) {
    var expected_loc = patches[x].start2 + delta;
    var text1 = this.diff_text1(patches[x].diffs);
    var start_loc;
    var end_loc = -1;
    if (text1.length > this.Match_MaxBits) {
      // patch_splitMax will only provide an oversized pattern in the case of
      // a monster delete.
      start_loc = this.match_main(text, text1.substring(0, this.Match_MaxBits),
                                  expected_loc);
      if (start_loc != -1) {
        end_loc = this.match_main(text,
            text1.substring(text1.length - this.Match_MaxBits),
            expected_loc + text1.length - this.Match_MaxBits);
        if (end_loc == -1 || start_loc >= end_loc) {
          // Can't find valid trailing context.  Drop this patch.
          start_loc = -1;
        }
      }
    } else {
      start_loc = this.match_main(text, text1, expected_loc);
    }
    if (start_loc == -1) {
      // No match found.  :(
      results[x] = false;
      // Subtract the delta for this failed patch from subsequent patches.
      delta -= patches[x].length2 - patches[x].length1;
    } else {
      // Found a match.  :)
      results[x] = true;
      delta = start_loc - expected_loc;
      var text2;
      if (end_loc == -1) {
        text2 = text.substring(start_loc, start_loc + text1.length);
      } else {
        text2 = text.substring(start_loc, end_loc + this.Match_MaxBits);
      }
      if (text1 == text2) {
        // Perfect match, just shove the replacement text in.
        text = text.substring(0, start_loc) +
               this.diff_text2(patches[x].diffs) +
               text.substring(start_loc + text1.length);
      } else {
        // Imperfect match.  Run a diff to get a framework of equivalent
        // indices.
        var diffs = this.diff_main(text1, text2, false);
        if (text1.length > this.Match_MaxBits &&
            this.diff_levenshtein(diffs) / text1.length >
            this.Patch_DeleteThreshold) {
          // The end points match, but the content is unacceptably bad.
          results[x] = false;
        } else {
          this.diff_cleanupSemanticLossless(diffs);
          var index1 = 0;
          var index2;
          for (var y = 0; y < patches[x].diffs.length; y++) {
            var mod = patches[x].diffs[y];
            if (mod[0] !== DIFF_EQUAL) {
              index2 = this.diff_xIndex(diffs, index1);
            }
            if (mod[0] === DIFF_INSERT) {  // Insertion
              text = text.substring(0, start_loc + index2) + mod[1] +
                     text.substring(start_loc + index2);
            } else if (mod[0] === DIFF_DELETE) {  // Deletion
              text = text.substring(0, start_loc + index2) +
                     text.substring(start_loc + this.diff_xIndex(diffs,
                         index1 + mod[1].length));
            }
            if (mod[0] !== DIFF_DELETE) {
              index1 += mod[1].length;
            }
          }
        }
      }
    }
  }
  // Strip the padding off.
  text = text.substring(nullPadding.length, text.length - nullPadding.length);
  return [text, results];
};


/**
 * Add some padding on text start and end so that edges can match something.
 * Intended to be called only from within patch_apply.
 * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
 * @return {string} The padding string added to each side.
 */
diff_match_patch.prototype.patch_addPadding = function(patches) {
  var paddingLength = this.Patch_Margin;
  var nullPadding = '';
  for (var x = 1; x <= paddingLength; x++) {
    nullPadding += String.fromCharCode(x);
  }

  // Bump all the patches forward.
  for (var x = 0; x < patches.length; x++) {
    patches[x].start1 += paddingLength;
    patches[x].start2 += paddingLength;
  }

  // Add some padding on start of first diff.
  var patch = patches[0];
  var diffs = patch.diffs;
  if (diffs.length == 0 || diffs[0][0] != DIFF_EQUAL) {
    // Add nullPadding equality.
    diffs.unshift([DIFF_EQUAL, nullPadding]);
    patch.start1 -= paddingLength;  // Should be 0.
    patch.start2 -= paddingLength;  // Should be 0.
    patch.length1 += paddingLength;
    patch.length2 += paddingLength;
  } else if (paddingLength > diffs[0][1].length) {
    // Grow first equality.
    var extraLength = paddingLength - diffs[0][1].length;
    diffs[0][1] = nullPadding.substring(diffs[0][1].length) + diffs[0][1];
    patch.start1 -= extraLength;
    patch.start2 -= extraLength;
    patch.length1 += extraLength;
    patch.length2 += extraLength;
  }

  // Add some padding on end of last diff.
  patch = patches[patches.length - 1];
  diffs = patch.diffs;
  if (diffs.length == 0 || diffs[diffs.length - 1][0] != DIFF_EQUAL) {
    // Add nullPadding equality.
    diffs.push([DIFF_EQUAL, nullPadding]);
    patch.length1 += paddingLength;
    patch.length2 += paddingLength;
  } else if (paddingLength > diffs[diffs.length - 1][1].length) {
    // Grow last equality.
    var extraLength = paddingLength - diffs[diffs.length - 1][1].length;
    diffs[diffs.length - 1][1] += nullPadding.substring(0, extraLength);
    patch.length1 += extraLength;
    patch.length2 += extraLength;
  }

  return nullPadding;
};


/**
 * Look through the patches and break up any which are longer than the maximum
 * limit of the match algorithm.
 * Intended to be called only from within patch_apply.
 * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
 */
diff_match_patch.prototype.patch_splitMax = function(patches) {
  var patch_size = this.Match_MaxBits;
  for (var x = 0; x < patches.length; x++) {
    if (patches[x].length1 <= patch_size) {
      continue;
    }
    var bigpatch = patches[x];
    // Remove the big old patch.
    patches.splice(x--, 1);
    var start1 = bigpatch.start1;
    var start2 = bigpatch.start2;
    var precontext = '';
    while (bigpatch.diffs.length !== 0) {
      // Create one of several smaller patches.
      var patch = new diff_match_patch.patch_obj();
      var empty = true;
      patch.start1 = start1 - precontext.length;
      patch.start2 = start2 - precontext.length;
      if (precontext !== '') {
        patch.length1 = patch.length2 = precontext.length;
        patch.diffs.push([DIFF_EQUAL, precontext]);
      }
      while (bigpatch.diffs.length !== 0 &&
             patch.length1 < patch_size - this.Patch_Margin) {
        var diff_type = bigpatch.diffs[0][0];
        var diff_text = bigpatch.diffs[0][1];
        if (diff_type === DIFF_INSERT) {
          // Insertions are harmless.
          patch.length2 += diff_text.length;
          start2 += diff_text.length;
          patch.diffs.push(bigpatch.diffs.shift());
          empty = false;
        } else if (diff_type === DIFF_DELETE && patch.diffs.length == 1 &&
                   patch.diffs[0][0] == DIFF_EQUAL &&
                   diff_text.length > 2 * patch_size) {
          // This is a large deletion.  Let it pass in one chunk.
          patch.length1 += diff_text.length;
          start1 += diff_text.length;
          empty = false;
          patch.diffs.push([diff_type, diff_text]);
          bigpatch.diffs.shift();
        } else {
          // Deletion or equality.  Only take as much as we can stomach.
          diff_text = diff_text.substring(0,
              patch_size - patch.length1 - this.Patch_Margin);
          patch.length1 += diff_text.length;
          start1 += diff_text.length;
          if (diff_type === DIFF_EQUAL) {
            patch.length2 += diff_text.length;
            start2 += diff_text.length;
          } else {
            empty = false;
          }
          patch.diffs.push([diff_type, diff_text]);
          if (diff_text == bigpatch.diffs[0][1]) {
            bigpatch.diffs.shift();
          } else {
            bigpatch.diffs[0][1] =
                bigpatch.diffs[0][1].substring(diff_text.length);
          }
        }
      }
      // Compute the head context for the next patch.
      precontext = this.diff_text2(patch.diffs);
      precontext =
          precontext.substring(precontext.length - this.Patch_Margin);
      // Append the end context for this patch.
      var postcontext = this.diff_text1(bigpatch.diffs)
                            .substring(0, this.Patch_Margin);
      if (postcontext !== '') {
        patch.length1 += postcontext.length;
        patch.length2 += postcontext.length;
        if (patch.diffs.length !== 0 &&
            patch.diffs[patch.diffs.length - 1][0] === DIFF_EQUAL) {
          patch.diffs[patch.diffs.length - 1][1] += postcontext;
        } else {
          patch.diffs.push([DIFF_EQUAL, postcontext]);
        }
      }
      if (!empty) {
        patches.splice(++x, 0, patch);
      }
    }
  }
};


/**
 * Take a list of patches and return a textual representation.
 * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects.
 * @return {string} Text representation of patches.
 */
diff_match_patch.prototype.patch_toText = function(patches) {
  var text = [];
  for (var x = 0; x < patches.length; x++) {
    text[x] = patches[x];
  }
  return text.join('');
};


/**
 * Parse a textual representation of patches and return a list of Patch objects.
 * @param {string} textline Text representation of patches.
 * @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects.
 * @throws {!Error} If invalid input.
 */
diff_match_patch.prototype.patch_fromText = function(textline) {
  var patches = [];
  if (!textline) {
    return patches;
  }
  var text = textline.split('\n');
  var textPointer = 0;
  var patchHeader = /^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/;
  while (textPointer < text.length) {
    var m = text[textPointer].match(patchHeader);
    if (!m) {
      throw new Error('Invalid patch string: ' + text[textPointer]);
    }
    var patch = new diff_match_patch.patch_obj();
    patches.push(patch);
    patch.start1 = parseInt(m[1], 10);
    if (m[2] === '') {
      patch.start1--;
      patch.length1 = 1;
    } else if (m[2] == '0') {
      patch.length1 = 0;
    } else {
      patch.start1--;
      patch.length1 = parseInt(m[2], 10);
    }

    patch.start2 = parseInt(m[3], 10);
    if (m[4] === '') {
      patch.start2--;
      patch.length2 = 1;
    } else if (m[4] == '0') {
      patch.length2 = 0;
    } else {
      patch.start2--;
      patch.length2 = parseInt(m[4], 10);
    }
    textPointer++;

    while (textPointer < text.length) {
      var sign = text[textPointer].charAt(0);
      try {
        var line = decodeURI(text[textPointer].substring(1));
      } catch (ex) {
        // Malformed URI sequence.
        throw new Error('Illegal escape in patch_fromText: ' + line);
      }
      if (sign == '-') {
        // Deletion.
        patch.diffs.push([DIFF_DELETE, line]);
      } else if (sign == '+') {
        // Insertion.
        patch.diffs.push([DIFF_INSERT, line]);
      } else if (sign == ' ') {
        // Minor equality.
        patch.diffs.push([DIFF_EQUAL, line]);
      } else if (sign == '@') {
        // Start of next patch.
        break;
      } else if (sign === '') {
        // Blank line?  Whatever.
      } else {
        // WTF?
        throw new Error('Invalid patch mode "' + sign + '" in: ' + line);
      }
      textPointer++;
    }
  }
  return patches;
};


/**
 * Class representing one patch operation.
 * @constructor
 */
diff_match_patch.patch_obj = function() {
  /** @type {!Array.<!diff_match_patch.Diff>} */
  this.diffs = [];
  /** @type {?number} */
  this.start1 = null;
  /** @type {?number} */
  this.start2 = null;
  /** @type {number} */
  this.length1 = 0;
  /** @type {number} */
  this.length2 = 0;
};


/**
 * Emmulate GNU diff's format.
 * Header: @@ -382,8 +481,9 @@
 * Indicies are printed as 1-based, not 0-based.
 * @return {string} The GNU diff string.
 */
diff_match_patch.patch_obj.prototype.toString = function() {
  var coords1, coords2;
  if (this.length1 === 0) {
    coords1 = this.start1 + ',0';
  } else if (this.length1 == 1) {
    coords1 = this.start1 + 1;
  } else {
    coords1 = (this.start1 + 1) + ',' + this.length1;
  }
  if (this.length2 === 0) {
    coords2 = this.start2 + ',0';
  } else if (this.length2 == 1) {
    coords2 = this.start2 + 1;
  } else {
    coords2 = (this.start2 + 1) + ',' + this.length2;
  }
  var text = ['@@ -' + coords1 + ' +' + coords2 + ' @@\n'];
  var op;
  // Escape the body of the patch with %xx notation.
  for (var x = 0; x < this.diffs.length; x++) {
    switch (this.diffs[x][0]) {
      case DIFF_INSERT:
        op = '+';
        break;
      case DIFF_DELETE:
        op = '-';
        break;
      case DIFF_EQUAL:
        op = ' ';
        break;
    }
    text[x + 1] = op + encodeURI(this.diffs[x][1]) + '\n';
  }
  return text.join('').replace(/%20/g, ' ');
};


// Export these global variables so that they survive Google's JS compiler.
// In a browser, 'this' will be 'window'.
// Users of node.js should 'require' the uncompressed version since Google's
// JS compiler may break the following exports for non-browser environments.
this['diff_match_patch'] = diff_match_patch;
this['DIFF_DELETE'] = DIFF_DELETE;
this['DIFF_INSERT'] = DIFF_INSERT;
this['DIFF_EQUAL'] = DIFF_EQUAL;

},{}]},{},[1])
(1)
});