l20n.js

(function(window, undefined) {

function define(name, payload) {
  define.modules[name] = payload;
};

// un-instantiated modules
define.modules = {};
// instantiated modules
define.exports = {};

function normalize(path) {
  var parts = path.split('/');
  var normalized = [];
  for (var i = 0; i < parts.length; i++) {
    if (parts[i] == '.') {
      // don't add it to `normalized`
    } else if (parts[i] == '..') {
      normalized.pop();
    } else {
      normalized.push(parts[i]);
    }
  }
  return normalized.join('/');
}

function join(a, b) {
  return a ? a.trim().replace(/\/*$/, '/') + b.trim() : b.trim();
}

function dirname(path) {
  return path ? path.split('/').slice(0, -1).join('/') : null;
}

function req(leaf, name) {
  name = normalize(join(dirname(leaf), name));
  if (name in define.exports) {
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  }
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    throw new Error("Module not defined: " + name);
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    var reply = module(req.bind(null, name), exports, { id: name, uri: "" });
    module = (reply !== undefined) ? reply : exports;
  }
  return define.exports[name] = module;
};

// for the top-level required modules, leaf is null
var require = req.bind(null, null);
define('l20n/html', function(require) {
  'use strict';

  var DEBUG = false;

  var L20n = require('../l20n');
  var io = require('./platform/io');

  // absolute URLs start with a slash or contain a colon (for schema)
  var reAbsolute = /^\/|:/;

  // http://www.w3.org/International/questions/qa-scripts
  // XXX: Bug 884308: this should be defined by each localization independently
  var rtlLocales = ['ar', 'fa', 'he', 'ps', 'ur'];

  var whitelist = {
    elements: [
      'a', 'em', 'strong', 'small', 's', 'cite', 'q', 'dfn', 'abbr', 'data',
      'time', 'code', 'var', 'samp', 'kbd', 'sub', 'sup', 'i', 'b', 'u',
      'mark', 'ruby', 'rt', 'rp', 'bdi', 'bdo', 'span', 'br', 'wbr'
    ],
    attributes: {
      global: [ 'title', 'aria-label' ],
      a: [ 'download' ],
      area: [ 'download', 'alt' ],
      // value is special-cased in isAttrAllowed
      input: [ 'alt', 'placeholder' ],
      menuitem: [ 'label' ],
      menu: [ 'label' ],
      optgroup: [ 'label' ],
      option: [ 'label' ],
      track: [ 'label' ],
      img: [ 'alt' ],
      textarea: [ 'placeholder' ],
      th: [ 'abbr']
    }
  };

  // Start-up logic (pre-bootstrap)
  // =========================================================================

  var ctx = L20n.getContext(document.location.host);
  bindPublicAPI(ctx);

  var localizeHandler;
  var documentLocalized = false;

  // if the DOM is loaded, bootstrap now to fire 'DocumentLocalized'
  if (document.readyState === 'complete') {
    window.setTimeout(bootstrap);
  } else {
    // or wait for the DOM to be interactive to try to pretranslate it 
    // using the inline resources
    waitFor('interactive', bootstrap);
  }

  function waitFor(state, callback) {
    if (document.readyState === state) {
      return callback();
    }
    document.addEventListener('readystatechange', function() {
      if (document.readyState === state) {
        callback();
      }
    });
  }

  function bindPublicAPI(ctx) {
    if (DEBUG) {
      ctx.addEventListener('error', console.error.bind(console));
      ctx.addEventListener('warning', console.warn.bind(console));
    }
    ctx.localizeNode = function localizeNode(node) {
      var nodes = getNodes(node);
      var many = localizeHandler.extend(nodes.ids);
      for (var i = 0; i < nodes.nodes.length; i++) {
        translateNode(nodes.nodes[i], nodes.ids[i],
                      many.entities[nodes.ids[i]]);
      }
    };
    ctx.once = function once(callback) {
      if (documentLocalized) {
        callback();
      } else {
        var callAndRemove = function callAndRemove() {
          document.removeEventListener('DocumentLocalized', callAndRemove);
          callback();
        };
        document.addEventListener('DocumentLocalized', callAndRemove);
      }
    };
    document.l10n = ctx;
  }


  // Bootstrap: set up the context and call requestLocales()
  // ==========================================================================

  function bootstrap() {
    var headNode = document.head;
    var data =
      headNode.querySelector('script[type="application/l10n-data+json"]');
    if (data) {
      ctx.updateData(JSON.parse(data.textContent));
    }

    var link = headNode.querySelector('link[rel="localization"]');
    if (link) {
      loadManifest(link.href);
      return collectNodes();
    }

    var scripts = headNode.querySelectorAll('script[type="application/l20n"]');
    if (scripts.length) {
      for (var i = 0; i < scripts.length; i++) {
        if (scripts[i].hasAttribute('src')) {
          ctx.linkResource(scripts[i].src);
        } else {
          ctx.addResource(scripts[i].textContent);
        }
      }
      ctx.requestLocales();
      return collectNodes();
    }

    console.error('L20n: No resources found. (Put them above l20n.js.)');
  }

  function loadManifest(url) {
    io.load(url, function(err, text) {
      var manifest = parseManifest(text, url);
      setupCtxFromManifest(manifest);
    });
  }

  function parseManifest(text, url) {
    var manifest = JSON.parse(text);
    manifest.resources = manifest.resources.map(
      relativeToManifest.bind(this, url));
    return manifest;
  }

  function setDocumentLanguage(loc) {
    document.documentElement.lang = loc;
    document.documentElement.dir =
      rtlLocales.indexOf(loc) === -1 ? 'ltr' : 'rtl';
  }

  function setupCtxFromManifest(manifest) {
    // register available locales
    ctx.registerLocales(manifest.default_locale, manifest.locales);
    ctx.registerLocaleNegotiator(function(available, requested, defLoc) {
      // lazy-require Intl
      var Intl = require('./intl').Intl;
      var fallbackChain = Intl.prioritizeLocales(available, requested, defLoc);
      setDocumentLanguage(fallbackChain[0]);
      return fallbackChain;
    });

    // add resources
    var re = /{{\s*locale\s*}}/;
    manifest.resources.forEach(function(uri) {
      if (re.test(uri)) {
        ctx.linkResource(uri.replace.bind(uri, re));
      } else {
        ctx.linkResource(uri);
      }
    });

    // For now we just take navigator.language, but we'd prefer to get a list 
    // of locales that the user can read sorted by user's preference, see:
    //   https://bugzilla.mozilla.org/show_bug.cgi?id=889335
    // For IE we use navigator.browserLanguage, see:
    //   http://msdn.microsoft.com/en-us/library/ie/ms533542%28v=vs.85%29.aspx
    ctx.requestLocales(navigator.language || navigator.browserLanguage);

    return manifest;
  }

  function relativeToManifest(manifestUrl, url) {
    if (reAbsolute.test(url)) {
      return url;
    }
    var dirs = manifestUrl.split('/')
      .slice(0, -1)
      .concat(url.split('/'))
      .filter(function(elem) {
        return elem !== '.';
      });
    return dirs.join('/');
  }

  function fireLocalizedEvent() {
    var event = document.createEvent('Event');
    event.initEvent('DocumentLocalized', false, false);
    document.dispatchEvent(event);
  }


  // DOM Localization
  // ==========================================================================

  function collectNodes() {
    var nodes = getNodes(document);
    localizeHandler = ctx.localize(nodes.ids, function localizeHandler(l10n) {
      if (!nodes) {
        nodes = getNodes(document);
      }
      for (var i = 0; i < nodes.nodes.length; i++) {
        translateNode(nodes.nodes[i],
                      nodes.ids[i],
                      l10n.entities[nodes.ids[i]]);
      }

      // 'locales' in l10n.reason means that localize has been
      // called because of locale change
      if ('locales' in l10n.reason && l10n.reason.locales.length) {
        setDocumentLanguage(l10n.reason.locales[0]);
      }

      nodes = null;
      if (!documentLocalized) {
        documentLocalized = true;
        fireLocalizedEvent();
      }
    });
  }

  function getNodes(node) {
    var nodes = node.querySelectorAll('[data-l10n-id]');
    var ids = [];
    if (node.hasAttribute && node.hasAttribute('data-l10n-id')) {
      // include the root node in nodes (and ids)
      nodes = Array.prototype.slice.call(nodes);
      nodes.push(node);
    }
    for (var i = 0; i < nodes.length; i++) {
      ids.push(nodes[i].getAttribute('data-l10n-id'));
    }
    return {
      ids: ids,
      nodes: nodes
    };
  }

  function camelCaseToDashed(string) {
    return string
      .replace(/[A-Z]/g, function (match) {
        return '-' + match.toLowerCase();
      })
      .replace(/^-/, '');
  }

  function translateNode(node, id, entity) {
    if (!entity) {
      return;
    }
    if (entity.value) {
      // if there is no HTML in the translation nor no HTML entities are used, 
      // just replace the textContent
      if (entity.value.indexOf('<') === -1 &&
          entity.value.indexOf('&') === -1) {
        node.textContent = entity.value;
      } else {
        // otherwise, start with an inert template element and move its 
        // children into `node` but such that `node`'s own children are not 
        // replaced
        var translation = document.createElement('template');
        translation.innerHTML = entity.value;
        // overlay the node with the DocumentFragment
        overlayElement(node, translation.content);
      }
    }
    Object.keys(entity.attributes).forEach(function(key) {
      var attrName = camelCaseToDashed(key);
      if (isAttrAllowed({ name: attrName }, node)) {
        node.setAttribute(attrName, entity.attributes[key]);
      }
    });
  }

  // The goal of overlayElement is to move the children of `translationElement` 
  // into `sourceElement` such that `sourceElement`'s own children are not 
  // replaced, but onle have their text nodes and their attributes modified.
  //
  // We want to make it possible for localizers to apply text-level semantics to
  // the translations and make use of HTML entities.  At the same time, we 
  // don't trust translations so we need to filter unsafe elements and 
  // attribtues out and we don't want to break the Web by replacing elements to 
  // which third-party code might have created references (e.g. two-way 
  // bindings in MVC frameworks).
  function overlayElement(sourceElement, translationElement) {
    var result = document.createDocumentFragment();

    // take one node from translationElement at a time and check it against the 
    // whitelist or try to match it with a corresponding element in the source
    var childElement;
    while (childElement = translationElement.childNodes[0]) {
      translationElement.removeChild(childElement);

      if (childElement.nodeType === Node.TEXT_NODE) {
        result.appendChild(childElement);
        continue;
      }

      var sourceChild = getElementOfType(sourceElement, childElement);
      if (sourceChild) {
        // there is a corresponding element in the source, let's use it
        overlayElement(sourceChild, childElement);
        result.appendChild(sourceChild);
        continue;
      }

      if (isElementAllowed(childElement)) {
        for (var k = 0, attr; attr = childElement.attributes[k]; k++) {
          if (!isAttrAllowed(attr, childElement)) {
            childElement.removeAttribute(attr.name);
          }
        }
        result.appendChild(childElement);
        continue;
      }

      // otherwise just take this child's textContent
      var text = new Text(childElement.textContent);
      result.appendChild(text);
    }

    // clear `sourceElement` and append `result` which by this time contains 
    // `sourceElement`'s original children, overlayed with translation
    sourceElement.textContent = '';
    sourceElement.appendChild(result);

    // if we're overlaying a nested element, translate the whitelisted 
    // attributes; top-level attributes are handled in `translateNode`
    // XXX attributes previously set here for another language should be 
    // cleared if a new language doesn't use them; https://bugzil.la/922577
    if (translationElement.attributes) {
      for (var k = 0, attr; attr = translationElement.attributes[k]; k++) {
        if (isAttrAllowed(attr, sourceElement)) {
          sourceElement.setAttribute(attr.name, attr.value);
        }
      }
    }
  }

  // XXX the whitelist should be amendable; https://bugzil.la/922573
  function isElementAllowed(element) {
    return whitelist.elements.indexOf(element.tagName.toLowerCase()) !== -1;
  }

  function isAttrAllowed(attr, element) {
    var attrName = attr.name.toLowerCase();
    var tagName = element.tagName.toLowerCase();
    // is it a globally safe attribute?
    if (whitelist.attributes.global.indexOf(attrName) !== -1) {
      return true;
    }
    // are there no whitelisted attributes for this element?
    if (!whitelist.attributes[tagName]) {
      return false;
    }
    // is it allowed on this element?
    // XXX the whitelist should be amendable; https://bugzil.la/922573
    if (whitelist.attributes[tagName].indexOf(attrName) !== -1) {
      return true;
    }
    // special case for value on inputs with type button, reset, submit
    if (tagName === 'input' && attrName === 'value') {
      var type = element.type.toLowerCase();
      if (type === 'submit' || type === 'button' || type === 'reset') {
        return true;
      }
    }
    return false;
  }

  // ideally, we'd use querySelector(':scope > ELEMENT:nth-of-type(index)'),
  // but 1) :scope is not widely supported yet and 2) it doesn't work with 
  // DocumentFragments.  :scope is needed to query only immediate children
  // https://developer.mozilla.org/en-US/docs/Web/CSS/:scope
  function getElementOfType(context, element) {
    var index = getIndexOfType(element);
    var nthOfType = 0;
    for (var i = 0, child; child = context.children[i]; i++) {
      if (child.nodeType === Node.ELEMENT_NODE &&
          child.tagName === element.tagName) {
        if (nthOfType === index) {
          return child;
        }
        nthOfType++;
      }
    }
    return null;
  }

  function getIndexOfType(element) {
    var index = 0;
    var child;
    while (child = element.previousElementSibling) {
      if (child.tagName === element.tagName) {
        index++;
      }
    }
    return index;
  }

  // same as exports = L20n;
  return L20n;

});
define('l20n', function(require, exports) {
  'use strict';

  var Context = require('./l20n/context').Context;
  var Parser = require('./l20n/parser').Parser;
  var Compiler = require('./l20n/compiler').Compiler;

  exports.Context = Context;
  exports.Parser = Parser;
  exports.Compiler = Compiler;
  exports.getContext = function L20n_getContext(id) {
      return new Context(id);
  };

});
define('l20n/context', function(require, exports) {
  'use strict';

  var EventEmitter = require('./events').EventEmitter;
  var Parser = require('./parser').Parser;
  var Compiler = require('./compiler').Compiler;
  var RetranslationManager = require('./retranslation').RetranslationManager;

  // register globals with RetranslationManager
  require('./platform/globals');
  var io = require('./platform/io');

  function Resource(id, parser) {
    var self = this;

    this.id = id;
    this.resources = [];
    this.source = null;
    this.ast = {
      type: 'L20n',
      body: []
    };

    this.build = build;

    var _imports_positions = [];
    // absolute URLs start with a slash or contain a colon (for schema)
    var reAbsolute = /^\/|:/;

    function build(nesting, callback, sync) {
      if (nesting >= 7) {
        return callback(new ContextError('Too many nested imports.'));
      }

      if (self.source) {
        // Bug 908826 - Don't artificially force asynchronicity when only using 
        // addResource
        // https://bugzilla.mozilla.org/show_bug.cgi?id=908826
        return setTimeout(function() {
          parse();
        });
      } else {
        io.load(self.id, parse, sync);
      }

      function parse(err, text) {
        if (err) {
          return callback(err);
        } else if (text !== undefined) {
          self.source = text;
        }
        self.ast = parser.parse(self.source);
        buildImports();
      }

      function buildImports() {
        var imports = self.ast.body.filter(function(elem, i) {
          if (elem.type === 'ImportStatement') {
            _imports_positions.push(i);
            return true;
          }
          return false;
        });

        imports.forEach(function(imp) {
          var uri = relativeToSelf(imp.uri.content);
          var res = new Resource(uri, parser);
          self.resources.push(res);
        });

        var importsToBuild = self.resources.length;
        if (importsToBuild === 0) {
          return callback();
        }

        self.resources.forEach(function(res) {
          res.build(nesting + 1, resourceBuilt, sync);
        });

        function resourceBuilt(err) {
          if (err) {
            return callback(err);
          }
          importsToBuild--;
          if (importsToBuild === 0) {
            flatten();
          }
        }
      }

      function flatten() {
        for (var i = self.resources.length - 1; i >= 0; i--) {
          var pos = _imports_positions[i] || 0;
          Array.prototype.splice.apply(self.ast.body,
            [pos, 1].concat(self.resources[i].ast.body));
        }
        callback();
      }
    }

    function relativeToSelf(url) {
      if (self.id === null || reAbsolute.test(url)) {
        return url;
      }
      var dirs = self.id.split('/')
        .slice(0, -1)
        .concat(url.split('/'))
        .filter(function(elem) {
          return elem !== '.';
        });

      return dirs.join('/');
    }

  }

  function Locale(id, parser, compiler, emitter) {
    this.id = id;
    this.resources = [];
    this.entries = null;
    this.ast = {
      type: 'L20n',
      body: []
    };
    this.isReady = false;

    this.build = build;
    this.getEntry = getEntry;
    this.hasResource = hasResource;

    var self = this;

    function build(callback) {
      if (!callback) {
        var sync = true;
      }

      var resourcesToBuild = self.resources.length;
      if (resourcesToBuild === 0) {
        throw new ContextError('Locale has no resources');
      }

      var resourcesWithErrors = 0;
      self.resources.forEach(function(res) {
        res.build(0, resourceBuilt, sync);
      });

      function resourceBuilt(err) {
        if (err) {
          resourcesWithErrors++;
          emitter.emit(err instanceof ContextError ? 'error' : 'warning', err);
        }
        resourcesToBuild--;
        if (resourcesToBuild === 0) {
          if (resourcesWithErrors === self.resources.length) {
            // XXX Bug 908780 - Decide what to do when all resources in 
            // a locale are missing or broken
            // https://bugzilla.mozilla.org/show_bug.cgi?id=908780
            emitter.emit('error',
                         new ContextError('Locale has no valid resources'));
          }
          flatten();
        }
      }

      function flatten() {
        self.ast.body = self.resources.reduce(function(prev, curr) {
          return prev.concat(curr.ast.body);
        }, self.ast.body);
        compile();
      }

      function compile() {
        self.entries = compiler.compile(self.ast);
        self.isReady = true;
        if (callback) {
          callback();
        }
      }
    }

    function getEntry(id) {
      /* jshint validthis: true */
      if (this.entries.hasOwnProperty(id)) {
        return this.entries[id];
      }
      return undefined;
    }

    function hasResource(uri) {
      /* jshint validthis: true */
      return this.resources.some(function(res) {
        return res.id === uri;
      });
    }
  }

  function Context(id) {

    this.id = id;

    this.registerLocales = registerLocales;
    this.registerLocaleNegotiator = registerLocaleNegotiator;
    this.requestLocales = requestLocales;
    this.addResource = addResource;
    this.linkResource = linkResource;
    this.updateData = updateData;

    this.getSync = getSync;
    this.getEntitySync = getEntitySync;
    this.localize = localize;
    this.ready = ready;

    this.addEventListener = addEvent;
    this.removeEventListener = removeEvent;

    Object.defineProperty(this, 'supportedLocales', {
      get: function() { return _fallbackChain.slice(); },
      enumerable: true
    });

    var _data = {};

    // language negotiator function
    var _negotiator;

    // registered and available languages
    var _default = 'i-default';
    var _registered = [_default];
    var _requested = [];
    var _fallbackChain = [];
    // Locale objects corresponding to the registered languages
    var _locales = {};

    // URLs or text of resources (with information about the type) added via 
    // linkResource and addResource
    var _reslinks = [];

    var _isReady = false;
    var _isFrozen = false;
    var _emitter = new EventEmitter();
    var _parser = new Parser();
    var _compiler = new Compiler();

    var _retr = new RetranslationManager();

    var self = this;

    _parser.addEventListener('error', error);
    _compiler.addEventListener('error', warn);
    _compiler.setGlobals(_retr.globals);

    function extend(dst, src) {
      Object.keys(src).forEach(function(key) {
        if (src[key] === undefined) {
          // un-define (remove) the property from dst
          delete dst[key];
        } else if (typeof src[key] !== 'object') {
          // if the source property is a primitive, just copy it overwriting 
          // whatever the destination property is
          dst[key] = src[key];
        } else {
          // if the source property is an object, deep-copy it recursively
          if (typeof dst[key] !== 'object') {
            dst[key] = {};
          }
          extend(dst[key], src[key]);
        }
      });
    }

    function updateData(obj) {
      if (!obj || typeof obj !== 'object') {
        throw new ContextError('Context data must be a non-null object');
      }
      extend(_data, obj);
    }

    function getSync(id, data) {
      if (!_isReady) {
        throw new ContextError('Context not ready');
      }
      return getFromLocale.call(self, 0, id, data).value;
    }

    function getEntitySync(id, data) {
      if (!_isReady) {
        throw new ContextError('Context not ready');
      }
      return getFromLocale.call(self, 0, id, data);
    }

    function localize(ids, callback) {
      if (!callback) {
        throw new ContextError('No callback passed');
      }
      return bindLocalize.call(self, ids, callback);
    }

    function ready(callback) {
      if (_isReady) {
        setTimeout(callback);
      }
      addEvent('ready', callback);
    }

    function bindLocalize(ids, callback, reason) {
      /* jshint validthis: true */

      var bound = {
        // stop: fn
        extend: function extend(newIds) {
          for (var i = 0; i < newIds.length; i++) {
            if (ids.indexOf(newIds[i]) === -1) {
              ids.push(newIds[i]);
            }
          }
          if (!_isReady) {
            return;
          }
          var newMany = getMany.call(this, newIds);
          // rebind the callback in `_retr`: append new globals seen used in 
          // `newIds` and overwrite the callback with a new one which has the 
          // updated `ids`
          _retr.bindGet({
            id: callback,
            callback: bindLocalize.bind(this, ids, callback),
            globals: Object.keys(newMany.globalsUsed)
          }, true);
          return newMany;
        }.bind(this),
        stop: function stop() {
          _retr.unbindGet(callback);
        }.bind(this)
      };


      // if the ctx isn't ready, bind the callback and return
      if (!_isReady) {
        _retr.bindGet({
          id: callback,
          callback: bindLocalize.bind(this, ids, callback),
          globals: []
        });
        return bound;
      }

      // if the ctx is ready, retrieve the entities
      var many = getMany.call(this, ids);
      var l10n = {
        entities: many.entities,
        // `reason` might be undefined if context was ready before `localize` 
        // was called;  in that case, we pass `locales` so that this scenario 
        // is transparent for the callback
        reason: reason || { locales: _fallbackChain.slice() },
        stop: function() {
          _retr.unbindGet(callback);
        }
      };
      _retr.bindGet({
        id: callback,
        callback: bindLocalize.bind(this, ids, callback),
        globals: Object.keys(many.globalsUsed)
      });
      // callback may call bound.extend which will rebind it if needed;  for 
      // this to work it needs to be called after _retr.bindGet above;  
      // otherwise bindGet would listen to globals passed initially in 
      // many.globalsUsed
      callback(l10n);
      return bound;
    }

    function getMany(ids) {
      /* jshint validthis: true */
      var many = {
        entities: {},
        globalsUsed: {}
      };
      for (var i = 0, id; id = ids[i]; i++) {
        many.entities[id] = getEntitySync.call(this, id);
        for (var global in many.entities[id].globals) {
          if (many.entities[id].globals.hasOwnProperty(global)) {
            many.globalsUsed[global] = true;
          }
        }
      }
      return many;
    }

    function getFromLocale(cur, id, data, prevSource) {
      /* jshint validthis: true */
      var loc = _fallbackChain[cur];
      if (!loc) {
        error(new RuntimeError('Unable to get translation', id,
                               _fallbackChain));
        // imitate the return value of Compiler.Entity.get
        return {
          value: prevSource ? prevSource.source : id,
          attributes: {},
          globals: {},
          locale: prevSource ? prevSource.loc : null
        };
      }
      var locale = getLocale(loc);

      if (!locale.isReady) {
        // build without a callback, synchronously
        locale.build(null);
      }

      var entry = locale.getEntry(id);

      // if the entry is missing, just go to the next locale immediately
      if (entry === undefined) {
        warn(new TranslationError('Not found', id, _fallbackChain, locale));
        return getFromLocale.call(this, cur + 1, id, data, prevSource);
      }

      // otherwise, try to get the value of the entry
      var value;
      try {
        value = entry.get(getArgs.call(this, data));
      } catch (e) {
        if (e instanceof Compiler.RuntimeError) {
          error(new TranslationError(e.message, id, _fallbackChain, locale));
          if (e instanceof Compiler.ValueError) {
            // salvage the source string which the compiler wasn't able to 
            // evaluate completely;  this is still better than returning the 
            // identifer;  prefer a source string from locales earlier in the 
            // fallback chain, if available
            var source = prevSource || { source: e.source, loc: locale.id };
            return getFromLocale.call(this, cur + 1, id, data, source);
          }
          return getFromLocale.call(this, cur + 1, id, data, prevSource);
        } else {
          throw error(e);
        }
      }
      value.locale = locale.id;
      return value;
    }

    function getArgs(extra) {
      if (!extra) {
        return _data;
      }
      var args = {};
      // deep-clone _data first
      extend(args, _data);
      // overwrite args with the extra args passed to the `get` call
      extend(args, extra);
      return args;
    }

    function addResource(text) {
      if (_isFrozen) {
        throw new ContextError('Context is frozen');
      }
      _reslinks.push(['text', text]);
    }

    function add(text, locale) {
      var res = new Resource(null, _parser);
      res.source = text;
      locale.resources.push(res);
    }

    function linkResource(uri) {
      if (_isFrozen) {
        throw new ContextError('Context is frozen');
      }
      _reslinks.push([typeof uri === 'function' ? 'template' : 'uri', uri]);
    }

    function link(uri, locale) {
      if (!locale.hasResource(uri)) {
        var res = new Resource(uri, _parser);
        locale.resources.push(res);
      }
    }

    function registerLocales(defLocale, available) {
      if (_isFrozen) {
        throw new ContextError('Context is frozen');
      }

      if (defLocale === undefined) {
        return;
      }

      _default = defLocale;
      _registered = [];

      if (!available) {
        available = [];
      }
      available.push(defLocale);

      // uniquify `available` into `_registered`
      available.forEach(function(loc) {
        if (typeof loc !== 'string') {
          throw new ContextError('Language codes must be strings');
        }
        if (_registered.indexOf(loc) === -1) {
          _registered.push(loc);
        }
      });
    }

    function registerLocaleNegotiator(negotiator) {
      if (_isFrozen) {
        throw new ContextError('Context is frozen');
      }
      _negotiator = negotiator;
    }

    function getLocale(loc) {
      if (_locales[loc]) {
        return _locales[loc];
      }
      var locale = new Locale(loc, _parser, _compiler, _emitter);
      _locales[loc] = locale;
      // populate the locale with resources
      for (var j = 0; j < _reslinks.length; j++) {
        var res = _reslinks[j];
        if (res[0] === 'text') {
          // a resource added via addResource(String)
          add(res[1], locale);
        } else if (res[0] === 'uri') {
          // a resource added via linkResource(String)
          link(res[1], locale);
        } else {
          // a resource added via linkResource(Function);  the function 
          // passed is a URL template and it takes the current locale's code 
          // as an argument
          link(res[1](locale.id), locale);
        }
      }
      return locale;
    }

    function requestLocales() {
      if (_isFrozen && !_isReady) {
        throw new ContextError('Context not ready');
      }

      if (_reslinks.length === 0) {
        warn(new ContextError('Context has no resources; not freezing'));
        return;
      }

      _isFrozen = true;
      _requested = Array.prototype.slice.call(arguments);

      if (_requested.length) {
        _requested.forEach(function(loc) {
          if (typeof loc !== 'string') {
            throw new ContextError('Language codes must be strings');
          }
        });
      }

      // the whole language negotiation process can be asynchronous;  for now 
      // we just use _registered as the list of all available locales, but in 
      // the future we might asynchronously try to query a language pack 
      // service of sorts for its own list of locales supported for this 
      // context
      if (!_negotiator) {
        var Intl = require('./intl').Intl;
        _negotiator = Intl.prioritizeLocales;
      }
      var fallbackChain = _negotiator(_registered, _requested, _default,
                                      freeze);
      // if the negotiator returned something, freeze synchronously
      if (fallbackChain) {
        freeze(fallbackChain);
      }
    }

    function freeze(fallbackChain) {
      var locale = getLocale(fallbackChain[0]);
      if (locale.isReady) {
        setReady(fallbackChain);
      } else {
        locale.build(setReady.bind(null, fallbackChain));
      }
    }

    function setReady(fallbackChain) {
      _fallbackChain = fallbackChain;
      _isReady = true;
      _retr.all(_fallbackChain.slice());
      _emitter.emit('ready');
    }

    function addEvent(type, listener) {
      _emitter.addEventListener(type, listener);
    }

    function removeEvent(type, listener) {
      _emitter.removeEventListener(type, listener);
    }

    function warn(e) {
      _emitter.emit('warning', e);
      return e;
    }

    function error(e) {
      _emitter.emit('error', e);
      return e;
    }
  }

  Context.Error = ContextError;
  Context.RuntimeError = RuntimeError;
  Context.TranslationError = TranslationError;

  function ContextError(message) {
    this.name = 'ContextError';
    this.message = message;
  }
  ContextError.prototype = Object.create(Error.prototype);
  ContextError.prototype.constructor = ContextError;

  function RuntimeError(message, id, supported) {
    ContextError.call(this, message);
    this.name = 'RuntimeError';
    this.entity = id;
    this.supportedLocales = supported.slice();
    this.message = id + ': ' + message + '; tried ' + supported.join(', ');
  }
  RuntimeError.prototype = Object.create(ContextError.prototype);
  RuntimeError.prototype.constructor = RuntimeError;

  function TranslationError(message, id, supported, locale) {
    RuntimeError.call(this, message, id, supported);
    this.name = 'TranslationError';
    this.locale = locale.id;
    this.message = '[' + this.locale + '] ' + id + ': ' + message;
  }
  TranslationError.prototype = Object.create(RuntimeError.prototype);
  TranslationError.prototype.constructor = TranslationError;

  exports.Context = Context;

});
define('l20n/events', function(require, exports) {
  'use strict';

  function EventEmitter() {
    this._listeners = {};
  }

  EventEmitter.prototype.emit = function ee_emit() {
    var args = Array.prototype.slice.call(arguments);
    var type = args.shift();
    if (!this._listeners[type]) {
      return false;
    }
    var typeListeners = this._listeners[type].slice();
    for (var i = 0; i < typeListeners.length; i++) {
      typeListeners[i].apply(this, args);
    }
    return true;
  };

  EventEmitter.prototype.addEventListener = function ee_add(type, listener) {
    if (!this._listeners[type]) {
      this._listeners[type] = [];
    }
    this._listeners[type].push(listener);
    return this;
  };

  EventEmitter.prototype.removeEventListener = function ee_rm(type, listener) {
    var typeListeners = this._listeners[type];
    var pos = typeListeners.indexOf(listener);
    if (pos === -1) {
      return this;
    }
    typeListeners.splice(pos, 1);
    return this;
  };

  exports.EventEmitter = EventEmitter;

});
define('l20n/parser', function(require, exports) {
  'use strict';

  var EventEmitter = require('./events').EventEmitter;

  function Parser(throwOnErrors) {

    /* Public */

    this.parse = parse;
    this.addEventListener = addEvent;
    this.removeEventListener = removeEvent;

    /* Private */

    var MAX_PLACEABLES = 100;

    var _source, _index, _length, _emitter;

    var getL20n;
    if (throwOnErrors) {
      getL20n = getL20nPlain;
    } else {
      _emitter = new EventEmitter();
      getL20n = getL20nWithRecover;
    }

    function getComment() {
      _index += 2;
      var start = _index;
      var end = _source.indexOf('*/', start);
      if (end === -1) {
        throw error('Comment without closing tag');
      }
      _index = end + 2;
      return {
        type: 'Comment',
        content: _source.slice(start, end)
      };
    }

    function getAttributes() {
      var attrs = [];
      var attr, ws1, ch;
 
      while (true) {
        attr = getKVPWithIndex('Attribute');
        attr.local = attr.key.name.charAt(0) === '_';
        attrs.push(attr);
        ws1 = getRequiredWS();
        ch = _source.charAt(_index);
        if (ch === '>') {
          break;
        } else if (!ws1) {
          throw error('Expected ">"');
        }
      }
      return attrs;
    }

    function getKVP(type) {
      var key = getIdentifier();
      getWS();
      if (_source.charAt(_index) !== ':') {
        throw error('Expected ":"');
      }
      ++_index;
      getWS();
      return {
        type: type,
        key: key,
        value: getValue()
      };
    }

    function getKVPWithIndex(type) {
      var key = getIdentifier();
      var index = [];

      if (_source.charAt(_index) === '[') {
        ++_index;
        getWS();
        index = getItemList(getExpression, ']');
      }
      getWS();
      if (_source.charAt(_index) !== ':') {
        throw error('Expected ":"');
      }
      ++_index;
      getWS();
      return {
        type: type,
        key: key,
        value: getValue(),
        index: index
      };
    }

    function getHash() {
      ++_index;
      getWS();
      var defItem, hi, comma, hash = [];
      var hasDefItem = false;
      while (true) {
        defItem = false;
        if (_source.charAt(_index) === '*') {
          ++_index;
          if (hasDefItem) {
            throw error('Default item redefinition forbidden');
          }
          defItem = true;
          hasDefItem = true;
        }
        hi = getKVP('HashItem');
        hi['default'] = defItem;
        hash.push(hi);
        getWS();

        comma = _source.charAt(_index) === ',';
        if (comma) {
          ++_index;
          getWS();
        }
        if (_source.charAt(_index) === '}') {
          ++_index;
          break;
        }
        if (!comma) {
          throw error('Expected "}"');
        }
      }
      return {
        type: 'Hash',
        content: hash
      };
    }

    function _unescapeString() {
      var ch = _source.charAt(++_index);
      var cc;
      if (ch === 'u') { // special case for unicode
        var ucode = '';
        for (var i = 0; i < 4; i++) {
          ch = _source[++_index];
          cc = ch.charCodeAt(0);
          if ((cc > 96 && cc < 103) || // a-f
              (cc > 64 && cc < 71) || // A-F
              (cc > 47 && cc < 58)) { // 0-9
                ucode += ch;
              } else {
                throw error('Illegal unicode escape sequence');
              }
        }
        return String.fromCharCode(parseInt(ucode, 16));
      }
      return ch;
    }

    function getComplexString(opchar, opcharLen) {
      var body = null;
      var buf = '';
      var placeables = 0;
      var ch;

      _index += opcharLen - 1;

      var start = _index + 1;

      walkChars:
      while (true) {
        ch = _source.charAt(++_index);
        switch (ch) {
          case '\\':
            buf += _unescapeString();
            break;
          case '{':
            /* We want to go to default unless {{ */
            /* jshint -W086 */
            if (_source.charAt(_index + 1) === '{') {
              if (body === null) {
                body = [];
              }
              if (placeables > MAX_PLACEABLES - 1) {
                throw error('Too many placeables, maximum allowed is ' +
                    MAX_PLACEABLES);
              }
              if (buf) {
                body.push({
                  type: 'String',
                  content: buf
                });
              }
              _index += 2;
              getWS();
              body.push(getExpression());
              getWS();
              if (_source.charAt(_index) !== '}' ||
                  _source.charAt(_index + 1) !== '}') {
                    throw error('Expected "}}"');
                  }
              _index += 1;
              placeables++;
              
              buf = '';
              break;
            }
          default:
            if (opcharLen === 1) {
              if (ch === opchar) {
                _index++;
                break walkChars;
              }
            } else {
              if (ch === opchar[0] &&
                  _source.charAt(_index + 1) === ch &&
                  _source.charAt(_index + 2) === ch) {
                _index += 3;
                break walkChars;
              }
            }
            buf += ch;
            if (_index + 1 >= _length) {
              throw error('Unclosed string literal');
            }
        }
      }
      if (body === null) {
        return {
          type: 'String',
          content: buf
        };
      }
      if (buf.length) {
        body.push({
          type: 'String',
          content: buf
        });
      }
      return {
        type: 'ComplexString',
        content: body,
        source: _source.slice(start, _index - opcharLen)
      };
    }

    function getString(opchar, opcharLen) {
      var opcharPos = _source.indexOf(opchar, _index + opcharLen);
      var placeablePos, escPos, buf;

      if (opcharPos === -1) {
        throw error('Unclosed string literal');
      }
      buf = _source.slice(_index + opcharLen, opcharPos);

      placeablePos = buf.indexOf('{{');
      if (placeablePos !== -1) {
        return getComplexString(opchar, opcharLen);
      } else {
        escPos = buf.indexOf('\\');
        if (escPos !== -1) {
          return getComplexString(opchar, opcharLen);
        }
      }

      _index = opcharPos + opcharLen;

      return {
        type: 'String',
        content: buf
      };
    }

    function getValue(optional, ch) {
      if (ch === undefined) {
        ch = _source.charAt(_index);
      }
      if (ch === '\'' || ch === '"') {
        if (ch === _source.charAt(_index + 1) &&
            ch === _source.charAt(_index + 2)) {
          return getString(ch + ch + ch, 3);
        }
        return getString(ch, 1);
      }
      if (ch === '{') {
        return getHash();
      }
      if (!optional) {
        throw error('Unknown value type');
      }
      return null;
    }


    function getRequiredWS() {
      var pos = _index;
      var cc = _source.charCodeAt(pos);
      // space, \n, \t, \r
      while (cc === 32 || cc === 10 || cc === 9 || cc === 13) {
        cc = _source.charCodeAt(++_index);
      }
      return _index !== pos;
    }

    function getWS() {
      var cc = _source.charCodeAt(_index);
      // space, \n, \t, \r
      while (cc === 32 || cc === 10 || cc === 9 || cc === 13) {
        cc = _source.charCodeAt(++_index);
      }
    }

    function getVariable() {
      ++_index;
      return {
        type: 'VariableExpression',
        id: getIdentifier()
      };
    }

    function getIdentifier() {
      var index = _index;
      var start = index;
      var source = _source;
      var cc = source.charCodeAt(start);

      // a-zA-Z_
      if ((cc < 97 || cc > 122) && (cc < 65 || cc > 90) && cc !== 95) {
        throw error('Identifier has to start with [a-zA-Z_]');
      }

      cc = source.charCodeAt(++index);
      while ((cc >= 97 && cc <= 122) || // a-z
             (cc >= 65 && cc <= 90) ||  // A-Z
             (cc >= 48 && cc <= 57) ||  // 0-9
             cc === 95) {               // _
        cc = source.charCodeAt(++index);
      }
      _index = index;
      return {
        type: 'Identifier',
        name: source.slice(start, index)
      };
    }

    function getImportStatement() {
      _index += 6;
      if (_source.charAt(_index) !== '(') {
        throw error('Expected "("');
      }
      ++_index;
      getWS();
      var uri = getString(_source.charAt(_index), 1);
      getWS();
      if (_source.charAt(_index) !== ')') {
        throw error('Expected ")"');
      }
      ++_index;
      return {
        type: 'ImportStatement',
        uri: uri
      };
    }

    function getMacro(id) {
      if (id.name.charAt(0) === '_') {
        throw error('Macro ID cannot start with "_"');
      }
      ++_index;
      var idlist = getItemList(getVariable, ')');
      getRequiredWS();

      if (_source.charAt(_index) !== '{') {
        throw error('Expected "{"');
      }
      ++_index;
      getWS();
      var exp = getExpression();
      getWS();
      if (_source.charAt(_index) !== '}') {
        throw error('Expected "}"');
      }
      ++_index;
      getWS();
      if (_source.charCodeAt(_index) !== 62) {
        throw error('Expected ">"');
      }
      ++_index;
      return {
        type: 'Macro',
        id: id,
        args: idlist,
        expression: exp
      };
    }

    function getEntity(id, index) {
      if (!getRequiredWS()) {
        throw error('Expected white space');
      }

      var ch = _source.charAt(_index);
      var value = getValue(true, ch);
      var attrs = null;
      if (value === null) {
        if (ch === '>') {
          throw error('Expected ">"');
        }
        attrs = getAttributes();
      } else {
        var ws1 = getRequiredWS();
        if (_source.charAt(_index) !== '>') {
          if (!ws1) {
            throw error('Expected ">"');
          }
          attrs = getAttributes();
        }
      }

      // skip '>'
      ++_index;
      return {
        type: 'Entity',
        id: id,
        value: value,
        index: index,
        attrs: attrs,
        local: (id.name.charCodeAt(0) === 95) // _
      };
    }

    function getEntry() {
      var cc = _source.charCodeAt(_index);

      // 60 == '<'
      if (cc === 60) {
        ++_index;
        var id = getIdentifier();
        cc = _source.charCodeAt(_index);
        // 40 == '('
        if (cc === 40) {
          return getMacro(id);
        }
        // 91 == '['
        if (cc === 91) {
          ++_index;
          return getEntity(id,
                           getItemList(getExpression, ']'));
        }
        return getEntity(id, null);
      }
      // 47, 42 == '/*'
      if (_source.charCodeAt(_index) === 47 &&
                 _source.charCodeAt(_index + 1) === 42) {
        return getComment();
      }
      if (_source.slice(_index, _index + 6) === 'import') {
        return getImportStatement();
      }
      throw error('Invalid entry');
    }

    function getL20nWithRecover() {
      var entries = [];

      getWS();
      while (_index < _length) {
        try {
          entries.push(getEntry());
        } catch (e) {
          if (e instanceof ParserError) {
            _emitter.emit('error', e);
            entries.push(recover());
          } else {
            throw e;
          }
        }
        if (_index < _length) {
          getWS();
        }
      }

      return {
        type: 'L20n',
        body: entries
      };
    }

    function getL20nPlain() {
      var entries = [];

      getWS();
      while (_index < _length) {
        entries.push(getEntry());
        if (_index < _length) {
          getWS();
        }
      }

      return {
        type: 'L20n',
        body: entries
      };
    }

    /* Public API functions */

    function parse(string) {
      _source = string;
      _index = 0;
      _length = _source.length;

      return getL20n();
    }

    function addEvent(type, listener) {
      if (!_emitter) {
        throw new Error('Emitter not available');
      }
      return _emitter.addEventListener(type, listener);
    }

    function removeEvent(type, listener) {
      if (!_emitter) {
        throw new Error('Emitter not available');
      }
      return _emitter.removeEventListener(type, listener);
    }

    /* Expressions */

    function getExpression() {
      return getConditionalExpression();
    }

    function getPrefixExpression(token, cl, op, nxt) {
      var exp = nxt();
      var t, ch;
      while (true) {
        t = '';
        getWS();
        ch = _source.charAt(_index);
        if (token[0].indexOf(ch) === -1) {
          break;
        }
        t += ch;
        ++_index;
        if (token.length > 1) {
          ch = _source.charAt(_index);
          if (token[1] === ch) {
            ++_index;
            t += ch;
          } else if (token[2]) {
            --_index;
            return exp;
          }
        }
        getWS();
        exp = {
          type: cl,
          operator: {
            type: op,
            token: t
          },
          left: exp,
          right: nxt()
        };
      }
      return exp;
    }

    function getPostfixExpression(token, cl, op, nxt) {
      var cc = _source.charCodeAt(_index);
      if (token.indexOf(cc) === -1) {
        return nxt();
      }
      ++_index;
      getWS();
      return {
        type: cl,
        operator: {
          type: op,
          token: String.fromCharCode(cc)
        },
        argument: getPostfixExpression(token, cl, op, nxt)
      };
    }

    function getConditionalExpression() {
      var exp = getOrExpression();
      getWS();
      if (_source.charCodeAt(_index) !== 63) { // ?
        return exp;
      }
      ++_index;
      getWS();
      var consequent = getExpression();
      getWS();
      if (_source.charCodeAt(_index) !== 58) { // :
        throw error('Expected ":"');
      }
      ++_index;
      getWS();
      return {
        type: 'ConditionalExpression',
        test: exp,
        consequent: consequent,
        alternate: getExpression()
      };
    }

    function getOrExpression() {
      return getPrefixExpression([['|'], '|', true],
                                 'LogicalExpression',
                                 'LogicalOperator',
                                 getAndExpression);
    }

    function getAndExpression() {
      return getPrefixExpression([['&'], '&', true],
                                 'LogicalExpression',
                                 'Logicalperator',
                                 getEqualityExpression);
    }

    function getEqualityExpression() {
      return getPrefixExpression([['=', '!'], '=', true],
                                 'BinaryExpression',
                                 'BinaryOperator',
                                 getRelationalExpression);
    }

    function getRelationalExpression() {
      return getPrefixExpression([['<', '>'], '=', false],
                                 'BinaryExpression',
                                 'BinaryOperator',
                                 getAdditiveExpression);
    }

    function getAdditiveExpression() {
      return getPrefixExpression([['+', '-']],
                                 'BinaryExpression',
                                 'BinaryOperator',
                                 getModuloExpression);
    }

    function getModuloExpression() {
      return getPrefixExpression([['%']],
                                 'BinaryExpression',
                                 'BinaryOperator',
                                 getMultiplicativeExpression);
    }

    function getMultiplicativeExpression() {
      return getPrefixExpression([['*']],
                                 'BinaryExpression',
                                 'BinaryOperator',
                                 getDividiveExpression);
    }

    function getDividiveExpression() {
      return getPrefixExpression([['/']],
                                 'BinaryExpression',
                                 'BinaryOperator',
                                 getUnaryExpression);
    }

    function getUnaryExpression() {
      return getPostfixExpression([43, 45, 33], // + - !
                                  'UnaryExpression',
                                  'UnaryOperator',
                                  getMemberExpression);
    }

    function getCallExpression(callee) {
      getWS();
      return {
        type: 'CallExpression',
        callee: callee,
        arguments: getItemList(getExpression, ')')
      };
    }

    function getAttributeExpression(idref, computed) {
      if (idref.type !== 'ParenthesisExpression' &&
          idref.type !== 'Identifier' &&
          idref.type !== 'ThisExpression') {
        throw error('AttributeExpression must have Identifier, This or ' +
                    'Parenthesis as left node');
      }
      var exp;
      if (computed) {
        getWS();
        exp = getExpression();
        getWS();
        if (_source.charAt(_index) !== ']') {
          throw error('Expected "]"');
        }
        ++_index;
        return {
          type: 'AttributeExpression',
          expression: idref,
          attribute: exp,
          computed: true
        };
      }
      exp = getIdentifier();
      return {
        type: 'AttributeExpression',
        expression: idref,
        attribute: exp,
        computed: false
      };
    }

    function getPropertyExpression(idref, computed) {
      var exp;
      if (computed) {
        getWS();
        exp = getExpression();
        getWS();
        if (_source.charAt(_index) !== ']') {
          throw error('Expected "]"');
        }
        ++_index;
        return {
          type: 'PropertyExpression',
          expression: idref,
          property: exp,
          computed: true
        };
      }
      exp = getIdentifier();
      return {
        type: 'PropertyExpression',
        expression: idref,
        property: exp,
        computed: false
      };
    }

    function getMemberExpression() {
      var exp = getParenthesisExpression();
      var cc;

      // 46: '.'
      // 40: '('
      // 58: ':'
      // 91: '['
      while (true) {
        cc = _source.charCodeAt(_index);
        if (cc === 46 || cc === 91) { // . or [
          ++_index;
          exp = getPropertyExpression(exp, cc === 91);
        } else if (cc === 58 &&
                   _source.charCodeAt(_index + 1) === 58) { // ::
          _index += 2;
          if (_source.charCodeAt(_index) === 91) { // [
            ++_index;
            exp = getAttributeExpression(exp, true);
          } else {
            exp = getAttributeExpression(exp, false);
          }
        } else if (cc === 40) { // (
          ++_index;
          exp = getCallExpression(exp);
        } else {
          break;
        }
      }
      return exp;
    }

    function getParenthesisExpression() {
      // 40 == (
      if (_source.charCodeAt(_index) === 40) {
        ++_index;
        getWS();
        var pexp = {
          type: 'ParenthesisExpression',
          expression: getExpression()
        };
        getWS();
        if (_source.charCodeAt(_index) !== 41) {
          throw error('Expected ")"');
        }
        ++_index;
        return pexp;
      }
      return getPrimaryExpression();
    }

    function getPrimaryExpression() {
      var pos = _index;
      var cc = _source.charCodeAt(pos);
      // number
      while (cc > 47 && cc < 58) {
        cc = _source.charCodeAt(++pos);
      }
      if (pos > _index) {
        var start = _index;
        _index = pos;
        return {
          type: 'Number',
          value: parseInt(_source.slice(start, pos), 10)
        };
      }

      switch (cc) {
        // value: '"{[
        case 39:
        case 34:
        case 123:
        case 91:
          return getValue();

        // variable: $
        case 36:
          return getVariable();

        // globals: @
        case 64:
          ++_index;
          return {
            type: 'GlobalsExpression',
              id: getIdentifier()
          };

        // this: ~
        case 126:
          ++_index;
          return {
            type: 'ThisExpression'
          };

        default:
          return getIdentifier();
      }
    }

    /* helper functions */

    function getItemList(callback, closeChar) {
      var ch;
      getWS();
      if (_source.charAt(_index) === closeChar) {
        ++_index;
        return [];
      }

      var items = [];

      while (true) {
        items.push(callback());
        getWS();
        ch = _source.charAt(_index);
        if (ch === ',') {
          ++_index;
          getWS();
        } else if (ch === closeChar) {
          ++_index;
          break;
        } else {
          throw error('Expected "," or "' + closeChar + '"');
        }
      }
      return items;
    }

    function error(message, pos) {
      if (pos === undefined) {
        pos = _index;
      }
      var start = _source.lastIndexOf('<', pos - 1);
      var lastClose = _source.lastIndexOf('>', pos - 1);
      start = lastClose > start ? lastClose + 1 : start;
      var context = _source.slice(start, pos + 10);

      var msg = message + ' at pos ' + pos + ': "' + context + '"';
      return new ParserError(msg, pos, context);
    }

    // This code is being called whenever we
    // hit ParserError.
    //
    // The strategy here is to find the closest entry opening
    // and skip forward to it.
    //
    // It may happen that the entry opening is in fact part of expression,
    // but this should just trigger another ParserError on the next char
    // and we'll have to scan for entry opening again until we're successful
    // or we run out of entry openings in the code.
    function recover() {
      var opening = _source.indexOf('<', _index);
      var junk;
      if (opening === -1) {
        junk = {
          'type': 'JunkEntry',
          'content': _source.slice(_index)
        };
        _index = _length;
        return junk;
      }
      junk = {
        'type': 'JunkEntry',
        'content': _source.slice(_index, opening)
      };
      _index = opening;
      return junk;
    }
  }

  /* ParserError class */

  Parser.Error = ParserError;

  function ParserError(message, pos, context) {
    this.name = 'ParserError';
    this.message = message;
    this.pos = pos;
    this.context = context;
  }
  ParserError.prototype = Object.create(Error.prototype);
  ParserError.prototype.constructor = ParserError;

  exports.Parser = Parser;

});
// This is L20n's on-the-fly compiler.  It takes the AST produced by the parser 
// and uses it to create a set of JavaScript objects and functions representing 
// entities and macros and other expressions.
//
// The module defines a `Compiler` singleton with a single method: `compile`.
// The result of the compilation is stored on the `entries` object passed as 
// the second argument to the `compile` function.  The third argument is 
// `globals`, an object whose properties provide information about the runtime 
// environment, e.g., the current hour, operating system etc.
//
// Main concepts
// -------------
//
// **Entities** and **attributes** are objects which are publicly available.  
// Their `toString` method is designed to be used by the L20n context to get 
// a string value of the entity, given the context data passed to the method.
//
// All other symbols defined by the grammar are implemented as expression 
// functions.  The naming convention is:
//
//   - capitalized first letters denote **expressions constructors**, e.g.
//   `PropertyExpression`.
//   - camel-case denotes **expression functions** returned by the 
//   constructors, e.g. `propertyExpression`.
//
// ### Constructors
//
// The constructor is called for every node in the AST.  It stores the 
// components of the expression which are constant and do not depend on the 
// calling context (an example of the latter would be the data passed by the 
// developer to the `toString` method).
// 
// ### Expression functions
//
// The constructor, when called, returns an expression function, which, in 
// turn, is called every time the expression needs to be evaluated.  The 
// evaluation call is context-dependend.  Every expression function takes two 
// mandatory arguments and one optional one:
//
// - `locals`, which stores the information about the currently evaluated 
// entity (`locals.__this__`).  It also stores the arguments passed to macros.
// - `ctxdata`, which is an object with data passed to the context by the 
// developer.  The developer can define data on the context, or pass it on 
// a per-call basis.
// - `key` (optional), which is a number or a string passed to a `HashLiteral` 
// expression denoting the member of the hash to return.  The member will be 
// another expression function which can then be evaluated further.
//
//
// Bubbling up the new _current_ entity
// ------------------------------------
//
// Every expression function returns an array [`newLocals`, `evaluatedValue`].
// The reason for this, and in particular for returning `newLocals`, is 
// important for understanding how the compiler works.
//
// In most of the cases. `newLocals` will be the same as the original `locals` 
// passed to the expression function during the evaluation call.  In some 
// cases, however, `newLocals.__this__` will reference a different entity than 
// `locals.__this__` did.  On runtime, as the compiler traverses the AST and 
// goes deeper into individual branches, when it hits an `identifier` and 
// evaluates it to an entity, it needs to **bubble up** this find back to the 
// top expressions in the chain.  This is so that the evaluation of the 
// top-most expressions in the branch (root being at the very top of the tree) 
// takes into account the new value of `__this__`.
//
// To illustrate this point, consider the following example.
//
// Two entities, `brandName` and `about` are defined as such:
// 
//     <brandName {
//       short: "Firefox",
//       long: "Mozilla {{ ~ }}"
//     }>
//     <about "About {{ brandName.long }}">
//
// Notice two `complexString`s: `about` references `brandName.long`, and 
// `brandName.long` references its own entity via `~`.  This `~` (meaning, the 
// current entity) must always reference `brandName`, even when called from 
// `about`.
//
// The AST for the `about` entity looks like this:
//
//     [Entity]
//       .id[Identifier]
//         .name[unicode "about"]
//       .index
//       .value[ComplexString]                      <1>
//         .content
//           [String]                               <2>
//             .content[unicode "About "]
//           [PropertyExpression]                   <3>
//             .expression[Identifier]              <4>
//               .name[unicode "brandName"]
//             .property[Identifier]
//               .name[unicode "long"]
//             .computed[bool=False]
//       .attrs
//       .local[bool=False]
//
// During the compilation the compiler will walk the AST top-down to the 
// deepest terminal leaves and will use expression constructors to create 
// expression functions for the components.  For instance, for `about`'s value, 
// the compiler will call `ComplexString()` to create an expression function 
// `complexString` <1> which will be assigned to the entity's value. The 
// `ComplexString` construtor, before it returns the `complexString` <1>, will 
// in turn call other expression constructors to create `content`: 
// a `stringLiteral` and a `propertyExpression`.  The `PropertyExpression` 
// contructor will do the same, etc...
//
// When `entity.getString(ctxdata)` is called by a third-party code, we need to 
// resolve the whole `complexString` <1> to return a single string value.  This 
// is what **resolving** means and it involves some recursion.  On the other 
// hand, **evaluating** means _to call the expression once and use what it 
// returns_.
// 
// The identifier expression sets `locals.__this__` to the current entity, 
// `about`, and tells the `complexString` <1> to _resolve_ itself.
//
// In order to resolve the `complexString` <1>, we start by resolving its first 
// member <2> to a string.  As we resolve deeper down, we bubble down `locals` 
// set by `toString`.  The first member of `content` turns out to simply be 
// a string that reads `About `.
//
// On to the second member, the propertyExpression <3>.  We bubble down 
// `locals` again and proceed to evaluate the `expression` field, which is an 
// `identifier`.  Note that we don't _resolve_ it to a string; we _evaluate_ it 
// to something that can be further used in other expressions, in this case, an 
// **entity** called `brandName`.
//
// Had we _resolved_ the `propertyExpression`, it would have resolve to 
// a string, and it would have been impossible to access the `long` member.  
// This leads us to an important concept:  the compiler _resolves_ expressions 
// when it expects a primitive value (a string, a number, a bool).  On the 
// other hand, it _evaluates_ expressions (calls them only once) when it needs 
// to work with them further, e.g. in order to access a member of the hash.
//
// This also explains why in the above example, once the compiler hits the 
// `brandName` identifier and changes the value of `locals.__this__` to the 
// `brandName` entity, this value doesn't bubble up all the way up to the 
// `about` entity.  All components of any `complexString` are _resolved_ by the 
// compiler until a primitive value is returned.  This logic lives in the 
// `_resolve` function.

define('l20n/compiler', function(require, exports) {
  // TODO change newcap to true?
  /* jshint strict: false, newcap: false */
  var EventEmitter = require('./events').EventEmitter;

  function Compiler() {

    // Public

    this.compile = compile;
    this.setGlobals = setGlobals;
    this.addEventListener = addEvent;
    this.removeEventListener = removeEvent;

    // Private

    var MAX_PLACEABLE_LENGTH = 2500;

    var _emitter = new EventEmitter();
    var _globals = null;
    var _references = {
      globals: {}
    };

    var _entryTypes = {
      Entity: Entity,
      Macro: Macro
    };

    // Public API functions

    function compile(ast, env) {
      if (!env) {
        env = {};
      }
      for (var i = 0, entry; entry = ast.body[i]; i++) {
        var Constructor = _entryTypes[entry.type];
        if (Constructor) {
          try {
            env[entry.id.name] = new Constructor(entry, env);
          } catch (e) {
            // rethrow non-compiler errors;
            requireCompilerError(e);
            // or, just ignore the error;  it's been already emitted
          }
        }
      }
      return env;
    }

    function setGlobals(globals) {
      _globals = globals;
      return true;
    }

    function addEvent(type, listener) {
      return _emitter.addEventListener(type, listener);
    }

    function removeEvent(type, listener) {
      return _emitter.removeEventListener(type, listener);
    }

    // utils

    function emit(Ctor, message, entry, source) {
      var e = new Ctor(message, entry, source);
      _emitter.emit('error', e);
      return e;
    }

    // The Entity object.
    function Entity(node, env) {
      this.id = node.id.name;
      this.env = env;
      this.local = node.local || false;
      this.index = null;
      this.attributes = null;
      this.publicAttributes = null;
      var i;
      if (node.index) {
        this.index = [];
        for (i = 0; i < node.index.length; i++) {
          this.index.push(IndexExpression(node.index[i], this));
        }
      }
      if (node.attrs) {
        this.attributes = {};
        this.publicAttributes = [];
        for (i = 0; i < node.attrs.length; i++) {
          var attr = node.attrs[i];
          this.attributes[attr.key.name] = new Attribute(attr, this);
          if (!attr.local) {
            this.publicAttributes.push(attr.key.name);
          }
        }
      }
      // Bug 817610 - Optimize a fast path for String entities in the Compiler
      if (node.value && node.value.type === 'String') {
        this.value = node.value.content;
      } else {
        this.value = LazyExpression(node.value, this, this.index);
      }
    }

    Entity.prototype.getString = function E_getString(ctxdata) {
      try {
        var locals = {
          __this__: this,
          __env__: this.env
        };
        return _resolve(this.value, locals, ctxdata);
      } catch (e) {
        requireCompilerError(e);
        // `ValueErrors` are not emitted in `StringLiteral` where they are 
        // created, because if the string in question is being evaluated in an 
        // index, we'll emit an `IndexError` instead.  To avoid duplication, 
        // `ValueErrors` are only be emitted if they actually make it to 
        // here.  See `IndexExpression` for an example of why they wouldn't.
        if (e instanceof ValueError) {
          _emitter.emit('error', e);
        }
        throw e;
      }
    };

    Entity.prototype.get = function E_get(ctxdata) {
      // reset `_references` to an empty state
      _references.globals = {};
      // evaluate the entity and its attributes;  if any globals are used in 
      // the process, `toString` will populate `_references.globals` 
      // accordingly.
      var entity = {
        value: this.getString(ctxdata),
        attributes: {}
      };
      if (this.publicAttributes) {
        entity.attributes = {};
        for (var i = 0, attr; attr = this.publicAttributes[i]; i++) {
          entity.attributes[attr] = this.attributes[attr].getString(ctxdata);
        }
      }
      entity.globals = _references.globals;
      return entity;
    };


    function Attribute(node, entity) {
      this.key = node.key.name;
      this.local = node.local || false;
      this.index = null;
      if (node.index) {
        this.index = [];
        for (var i = 0; i < node.index.length; i++) {
          this.index.push(IndexExpression(node.index[i], this));
        }
      }
      if (node.value && node.value.type === 'String') {
        this.value = node.value.content;
      } else {
        this.value = LazyExpression(node.value, entity, this.index);
      }
      this.entity = entity;
    }

    Attribute.prototype.getString = function A_getString(ctxdata) {
      try {
        var locals = {
          __this__: this.entity,
          __env__: this.entity.env
        };
        return _resolve(this.value, locals, ctxdata);
      } catch (e) {
        requireCompilerError(e);
        if (e instanceof ValueError) {
          _emitter.emit('error', e);
        }
        throw e;
      }
    };

    function Macro(node, env) {
      this.id = node.id.name;
      this.env = env;
      this.local = node.local || false;
      this.expression = LazyExpression(node.expression, this);
      this.args = node.args;
    }
    Macro.prototype._call = function M_call(args, ctxdata) {
      var locals = {
        __this__: this,
        __env__: this.env
      };
      // the number of arguments passed must equal the macro's arity
      if (this.args.length !== args.length) {
        throw new RuntimeError(this.id + '() takes exactly ' +
                               this.args.length + ' argument(s) (' +
                               args.length + ' given)');
      }
      for (var i = 0; i < this.args.length; i++) {
        locals[this.args[i].id.name] = args[i];
      }
      var final = this.expression(locals, ctxdata);
      locals = final[0];
      final = final[1];
      return [locals, _resolve(final, locals, ctxdata)];
    };


    var EXPRESSION_TYPES = {
      // Primary expressions.
      'Identifier': Identifier,
      'ThisExpression': ThisExpression,
      'VariableExpression': VariableExpression,
      'GlobalsExpression': GlobalsExpression,

      // Value expressions.
      'Number': NumberLiteral,
      'String': StringLiteral,
      'Hash': HashLiteral,
      'HashItem': Expression,
      'ComplexString': ComplexString,

      // Logical expressions.
      'UnaryExpression': UnaryExpression,
      'BinaryExpression': BinaryExpression,
      'LogicalExpression': LogicalExpression,
      'ConditionalExpression': ConditionalExpression,

      // Member expressions.
      'CallExpression': CallExpression,
      'PropertyExpression': PropertyExpression,
      'AttributeExpression': AttributeExpression,
      'ParenthesisExpression': ParenthesisExpression
    };

    // The 'dispatcher' expression constructor.  Other expression constructors 
    // call this to create expression functions for their components.  For 
    // instance, `ConditionalExpression` calls `Expression` to create
    // expression functions for its `test`, `consequent` and `alternate` 
    // symbols.
    function Expression(node, entry, index) {
      // An entity can have no value.  It will be resolved to `null`.
      if (!node) {
        return null;
      }
      if (!EXPRESSION_TYPES[node.type]) {
        throw emit('CompilationError', 'Unknown expression type' + node.type);
      }
      if (index) {
        index = index.slice();
      }
      return EXPRESSION_TYPES[node.type](node, entry, index);
    }

    function LazyExpression(node, entry, index) {
      // An entity can have no value.  It will be resolved to `null`.
      if (!node) {
        return null;
      }
      var expr;
      return function(locals, ctxdata, prop) {
        if (!expr) {
          expr = Expression(node, entry, index);
        }
        return expr(locals, ctxdata, prop);
      };
    }

    function _resolve(expr, locals, ctxdata) {
      // Bail out early if it's a primitive value or `null`.  This is exactly 
      // what we want.
      if (typeof expr === 'string' ||
          typeof expr === 'boolean' ||
          typeof expr === 'number' ||
          !expr) {
        return expr;
      }

      // Check if `expr` is an Entity or an Attribute
      if (expr.value !== undefined) {
        return _resolve(expr.value, locals, ctxdata);
      }

      // Check if `expr` is an expression
      if (typeof expr === 'function') {
        var current = expr(locals, ctxdata);
        locals = current[0];
        current = current[1];
        return _resolve(current, locals, ctxdata);
      }

      // Throw if `expr` is a macro
      if (expr.expression) {
        throw new RuntimeError('Uncalled macro: ' + expr.id);
      }

      // Throw if `expr` is a non-primitive from ctxdata or a global
      throw new RuntimeError('Cannot resolve ctxdata or global of type ' +
                             typeof expr);

    }

    function Identifier(node) {
      var name = node.name;
      return function identifier(locals) {
        if (!locals.__env__.hasOwnProperty(name)) {
          throw new RuntimeError('Reference to an unknown entry: ' + name);
        }
        // The only thing we care about here is the new `__this__` so we 
        // discard any other local variables.  Note that because this is an 
        // assignment to a local variable, the original `locals` passed is not 
        // changed.
        locals = {
          __this__: locals.__env__[name],
          __env__: locals.__env__
        };
        return [locals, locals.__this__];
      };
    }
    function ThisExpression() {
      return function thisExpression(locals) {
        return [locals, locals.__this__];
      };
    }
    function VariableExpression(node) {
      var name = node.id.name;
      return function variableExpression(locals, ctxdata) {
        if (locals.hasOwnProperty(name)) {
          // locals[name] is already a [locals, value] tuple on its own
          return locals[name];
        }
        if (!ctxdata || !ctxdata.hasOwnProperty(name)) {
          throw new RuntimeError('Reference to an unknown variable: ' + name);
        }
        return [locals, ctxdata[name]];
      };
    }
    function GlobalsExpression(node) {
      var name = node.id.name;
      return function globalsExpression(locals) {
        if (!_globals) {
          throw new RuntimeError('No globals set (tried @' + name + ')');
        }
        if (!_globals.hasOwnProperty(name)) {
          throw new RuntimeError('Reference to an unknown global: ' + name);
        }
        var value;
        try {
          value = _globals[name].get();
        } catch (e) {
          throw new RuntimeError('Cannot evaluate global ' + name);
        }
        _references.globals[name] = true;
        return [locals, value];
      };
    }
    function NumberLiteral(node) {
      return function numberLiteral(locals) {
        return [locals, node.value];
      };
    }
    function StringLiteral(node) {
      return function stringLiteral(locals, ctxdata, key) {
        // if a key was passed, throw;  checking arguments is more reliable 
        // than testing the value of key because if the key comes from context 
        // data it can be any type, also undefined
        if (key !== undefined) {
          throw new RuntimeError('Cannot get property of a string: ' + key);
        }
        return [locals, node.content];
      };
    }

    function ComplexString(node, entry) {
      var content = [];
      for (var i = 0; i < node.content.length; i++) {
        content.push(Expression(node.content[i], entry));
      }

      // Every complexString needs to have its own `dirty` flag whose state 
      // persists across multiple calls to the given complexString.  On the 
      // other hand, `dirty` must not be shared by all complexStrings.  Hence 
      // the need to define `dirty` as a variable available in the closure.  
      // Note that the anonymous function is a self-invoked one and it returns 
      // the closure immediately.
      return (function() {
        var dirty = false;
        return function complexString(locals, ctxdata, key) {
          if (key !== undefined) {
            throw new RuntimeError('Cannot get property of a string: ' + key);
          }
          if (dirty) {
            throw new RuntimeError('Cyclic reference detected');
          }
          dirty = true;
          var parts = [];
          try {
            for (var i = 0; i < content.length; i++) {
              var part = _resolve(content[i], locals, ctxdata);
              if (typeof part !== 'string' && typeof part !== 'number') {
                throw new RuntimeError('Placeables must be strings or ' +
                                       'numbers');
              }
              if (part.length > MAX_PLACEABLE_LENGTH) {
                throw new RuntimeError('Placeable has too many characters, ' +
                                       'maximum allowed is ' +
                                       MAX_PLACEABLE_LENGTH);
              }
              parts.push(part);
            }
          } catch (e) {
            requireCompilerError(e);
            // only throw, don't emit yet.  If the `ValueError` makes it to 
            // `getString()` it will be emitted there.  It might, however, be 
            // cought by `IndexExpression` and changed into a `IndexError`.  
            // See `IndexExpression` for more explanation.
            throw new ValueError(e.message, entry, node.source);
          } finally {
            dirty = false;
          }
          return [locals, parts.join('')];
        };
      })();
    }

    function IndexExpression(node, entry) {
      var expression = Expression(node, entry);

      // This is analogous to `ComplexString` in that an individual index can 
      // only be visited once during the resolution of an Entity.  `dirty` is 
      // set in a closure context of the returned function.
      return (function() {
        var dirty = false;
        return function indexExpression(locals, ctxdata) {
          if (dirty) {
            throw new RuntimeError('Cyclic reference detected');
          }
          dirty = true;
          var retval;
          try {
            // We need to resolve `expression` here so that we catch errors 
            // thrown deep within.  Without `_resolve` we might end up with an 
            // unresolved Entity object, and no "Cyclic reference detected" 
            // error would be thown.
            retval = _resolve(expression, locals, ctxdata);
          } catch (e) {
            // If it's an `IndexError` thrown deeper within `expression`, it 
            // has already been emitted by its `indexExpression`.  We can 
            // safely re-throw it here.
            if (e instanceof IndexError) {
              throw e;
            }

            // Otherwise, make sure it's a `RuntimeError` or a `ValueError` and 
            // throw and emit an `IndexError`.
            //
            // If it's a `ValueError` we want to replace it by an `IndexError` 
            // here so that `ValueErrors` from the index don't make their way 
            // up to the context.  The context only cares about ValueErrors 
            // thrown by the value of the entity it has requested, not entities 
            // used in the index.
            //
            // To illustrate this point with an example, consider the following 
            // two strings, where `foo` is a missing entity.
            //
            //     <prompt1["remove"] {
            //       remove: "Remove {{ foo }}?",
            //       keep: "Keep {{ foo }}?"
            //     }>
            //
            // `prompt1` will throw a `ValueError`.  The context can use it to 
            // display the source of the entity, i.e. `Remove {{ foo }}?`.  The 
            // index resolved properly, so at least we know that we're showing 
            // the right variant of the entity.
            //
            //     <prompt2["{{ foo }}"] {
            //       remove: "Remove file?",
            //       keep: "Keep file?"
            //     }>
            //
            // On the other hand, `prompt2` will throw an `IndexError`.  This 
            // is a more serious scenario for the context.  We should not 
            // assume that we know which variant to show to the user.  In fact, 
            // in the above (much contrived, but still) example, showing the 
            // incorrect variant will likely lead to data loss.  The context 
            // should be more strict in this case and should not try to recover 
            // from this error too hard.
            requireCompilerError(e);
            throw emit(IndexError, e.message, entry);
          } finally {
            dirty = false;
          }
          return [locals, retval];
        };
      })();
    }

    function HashLiteral(node, entry, index) {
      var content = {};
      // if absent, `defaultKey` and `defaultIndex` are undefined
      var defaultKey;
      var defaultIndex = index ? index.shift() : undefined;
      for (var i = 0; i < node.content.length; i++) {
        var elem = node.content[i];
        // use `elem.value` to skip `HashItem` and create the value right away
        content[elem.key.name] = Expression(elem.value, entry, index);
        if (elem.default) {
          defaultKey = elem.key.name;
        }
      }
      return function hashLiteral(locals, ctxdata, prop) {
        var keysToTry = [prop, defaultIndex, defaultKey];
        var keysTried = [];
        for (var i = 0; i < keysToTry.length; i++) {
          var key = _resolve(keysToTry[i], locals, ctxdata);
          if (key === undefined) {
            continue;
          }
          if (typeof key !== 'string') {
            throw emit(IndexError, 'Index must be a string', entry);
          }
          keysTried.push(key);
          if (content.hasOwnProperty(key)) {
            return [locals, content[key]];
          }
        }

        // If no valid key was found, throw an `IndexError`
        var message;
        if (keysTried.length) {
          message = 'Hash key lookup failed ' +
                        '(tried "' + keysTried.join('", "') + '").';
        } else {
          message = 'Hash key lookup failed.';
        }
        throw emit(IndexError, message, entry);
      };
    }


    function UnaryOperator(token, entry) {
      if (token === '-') return function negativeOperator(argument) {
        if (typeof argument !== 'number') {
          throw new RuntimeError('The unary - operator takes a number');
        }
        return -argument;
      };
      if (token === '+') return function positiveOperator(argument) {
        if (typeof argument !== 'number') {
          throw new RuntimeError('The unary + operator takes a number');
        }
        return +argument;
      };
      if (token === '!') return function notOperator(argument) {
        if (typeof argument !== 'boolean') {
          throw new RuntimeError('The ! operator takes a boolean');
        }
        return !argument;
      };
      throw emit(CompilationError, 'Unknown token: ' + token, entry);
    }
    function BinaryOperator(token, entry) {
      if (token === '==') return function equalOperator(left, right) {
        if ((typeof left !== 'number' || typeof right !== 'number') &&
            (typeof left !== 'string' || typeof right !== 'string')) {
          throw new RuntimeError('The == operator takes two numbers or ' +
                                 'two strings');
        }
        return left === right;
      };
      if (token === '!=') return function notEqualOperator(left, right) {
        if ((typeof left !== 'number' || typeof right !== 'number') &&
            (typeof left !== 'string' || typeof right !== 'string')) {
          throw new RuntimeError('The != operator takes two numbers or ' +
                                 'two strings');
        }
        return left !== right;
      };
      if (token === '<') return function lessThanOperator(left, right) {
        if (typeof left !== 'number' || typeof right !== 'number') {
          throw new RuntimeError('The < operator takes two numbers');
        }
        return left < right;
      };
      if (token === '<=') return function lessThanEqualOperator(left, right) {
        if (typeof left !== 'number' || typeof right !== 'number') {
          throw new RuntimeError('The <= operator takes two numbers');
        }
        return left <= right;
      };
      if (token === '>') return function greaterThanOperator(left, right) {
        if (typeof left !== 'number' || typeof right !== 'number') {
          throw new RuntimeError('The > operator takes two numbers');
        }
        return left > right;
      };
      if (token === '>=') {
        return function greaterThanEqualOperator(left, right) {
          if (typeof left !== 'number' || typeof right !== 'number') {
            throw new RuntimeError('The >= operator takes two numbers');
          }
          return left >= right;
        };
      }
      if (token === '+') return function addOperator(left, right) {
        if ((typeof left !== 'number' || typeof right !== 'number') &&
            (typeof left !== 'string' || typeof right !== 'string')) {
          throw new RuntimeError('The + operator takes two numbers or ' +
                                 'two strings');
        }
        return left + right;
      };
      if (token === '-') return function substractOperator(left, right) {
        if (typeof left !== 'number' || typeof right !== 'number') {
          throw new RuntimeError('The - operator takes two numbers');
        }
        return left - right;
      };
      if (token === '*') return function multiplyOperator(left, right) {
        if (typeof left !== 'number' || typeof right !== 'number') {
          throw new RuntimeError('The * operator takes two numbers');
        }
        return left * right;
      };
      if (token === '/') return function devideOperator(left, right) {
        if (typeof left !== 'number' || typeof right !== 'number') {
          throw new RuntimeError('The / operator takes two numbers');
        }
        if (right === 0) {
          throw new RuntimeError('Division by zero not allowed.');
        }
        return left / right;
      };
      if (token === '%') return function moduloOperator(left, right) {
        if (typeof left !== 'number' || typeof right !== 'number') {
          throw new RuntimeError('The % operator takes two numbers');
        }
        if (right === 0) {
          throw new RuntimeError('Modulo zero not allowed.');
        }
        return left % right;
      };
      throw emit(CompilationError, 'Unknown token: ' + token, entry);
    }
    function LogicalOperator(token, entry) {
      if (token === '&&') return function andOperator(left, right) {
        if (typeof left !== 'boolean' || typeof right !== 'boolean') {
          throw new RuntimeError('The && operator takes two booleans');
        }
        return left && right;
      };
      if (token === '||') return function orOperator(left, right) {
        if (typeof left !== 'boolean' || typeof right !== 'boolean') {
          throw new RuntimeError('The || operator takes two booleans');
        }
        return left || right;
      };
      throw emit(CompilationError, 'Unknown token: ' + token, entry);
    }
    function UnaryExpression(node, entry) {
      var operator = UnaryOperator(node.operator.token, entry);
      var argument = Expression(node.argument, entry);
      return function unaryExpression(locals, ctxdata) {
        return [locals, operator(_resolve(argument, locals, ctxdata))];
      };
    }
    function BinaryExpression(node, entry) {
      var left = Expression(node.left, entry);
      var operator = BinaryOperator(node.operator.token, entry);
      var right = Expression(node.right, entry);
      return function binaryExpression(locals, ctxdata) {
        return [locals, operator(
          _resolve(left, locals, ctxdata),
          _resolve(right, locals, ctxdata)
        )];
      };
    }
    function LogicalExpression(node, entry) {
      var left = Expression(node.left, entry);
      var operator = LogicalOperator(node.operator.token, entry);
      var right = Expression(node.right, entry);
      return function logicalExpression(locals, ctxdata) {
        return [locals, operator(
          _resolve(left, locals, ctxdata),
          _resolve(right, locals, ctxdata)
        )];
      };
    }
    function ConditionalExpression(node, entry) {
      var test = Expression(node.test, entry);
      var consequent = Expression(node.consequent, entry);
      var alternate = Expression(node.alternate, entry);
      return function conditionalExpression(locals, ctxdata) {
        var tested = _resolve(test, locals, ctxdata);
        if (typeof tested !== 'boolean') {
          throw new RuntimeError('Conditional expressions must test a ' +
                                 'boolean');
        }
        if (tested === true) {
          return consequent(locals, ctxdata);
        }
        return alternate(locals, ctxdata);
      };
    }

    function CallExpression(node, entry) {
      var callee = Expression(node.callee, entry);
      var args = [];
      for (var i = 0; i < node.arguments.length; i++) {
        args.push(Expression(node.arguments[i], entry));
      }
      return function callExpression(locals, ctxdata) {
        var evaluated_args = [];
        for (var i = 0; i < args.length; i++) {
          evaluated_args.push(args[i](locals, ctxdata));
        }
        // callee is an expression pointing to a macro, e.g. an identifier
        var macro = callee(locals, ctxdata);
        locals = macro[0];
        macro = macro[1];
        if (!macro.expression) {
          throw new RuntimeError('Expected a macro, got a non-callable.');
        }
        // Rely entirely on the platform implementation to detect recursion.
        // `Macro::_call` assigns `evaluated_args` to members of `locals`.
        return macro._call(evaluated_args, ctxdata);
      };
    }
    function PropertyExpression(node, entry) {
      var expression = Expression(node.expression, entry);
      var property = node.computed ?
        Expression(node.property, entry) :
        node.property.name;
      return function propertyExpression(locals, ctxdata) {
        var prop = _resolve(property, locals, ctxdata);
        if (typeof prop !== 'string') {
          throw new RuntimeError('Property name must evaluate to a string: ' +
                                 prop);
        }
        var parent = expression(locals, ctxdata);
        locals = parent[0];
        parent = parent[1];

        // At this point, `parent` can be anything and we need to do some 
        // type-checking to handle erros gracefully (bug 883664) and securely 
        // (bug 815962).

        // If `parent` is an Entity or an Attribute, `locals` has been 
        // correctly set up by Identifier
        if (parent && parent.value !== undefined) {
          if (typeof parent.value !== 'function') {
            throw new RuntimeError('Cannot get property of a ' +
                                   typeof parent.value + ': ' + prop);
          }
          return parent.value(locals, ctxdata, prop);
        }

        // If it's a hashLiteral or stringLiteral inside a hash, just call it
        if (typeof parent === 'function') {
          return parent(locals, ctxdata, prop);
        }
        if (parent && parent.expression) {
          throw new RuntimeError('Cannot get property of a macro: ' + prop);
        }

        // If `parent` is an object passed by the developer to the context 
        // (i.e., `expression` was a `VariableExpression`) or a global, return 
        // the member of the object corresponding to `prop`
        if (typeof parent === 'object') {
          if (parent === null) {
            throw new RuntimeError('Cannot get property of a null: ' + prop);
          }
          if (Array.isArray(parent)) {
            throw new RuntimeError('Cannot get property of an array: ' + prop);
          }
          if (!parent.hasOwnProperty(prop)) {
            throw new RuntimeError(prop + ' is not defined on the object.');
          }
          return [locals, parent[prop]];
        }

        // otherwise it's a primitive
        throw new RuntimeError('Cannot get property of a ' + typeof parent +
                               ': ' + prop);
      };
    }
    function AttributeExpression(node, entry) {
      var expression = Expression(node.expression, entry);
      var attribute = node.computed ?
        Expression(node.attribute, entry) :
        node.attribute.name;
      return function attributeExpression(locals, ctxdata) {
        var attr = _resolve(attribute, locals, ctxdata);
        var entity = expression(locals, ctxdata);
        locals = entity[0];
        entity = entity[1];
        if (!entity.attributes) {
          throw new RuntimeError('Cannot get attribute of a non-entity: ' +
                                 attr);
        }
        if (!entity.attributes.hasOwnProperty(attr)) {
          throw new RuntimeError(entity.id + ' has no attribute ' + attr);
        }
        return [locals, entity.attributes[attr]];
      };
    }
    function ParenthesisExpression(node, entry) {
      return Expression(node.expression, entry);
    }

  }

  Compiler.Error = CompilerError;
  Compiler.CompilationError = CompilationError;
  Compiler.RuntimeError = RuntimeError;
  Compiler.ValueError = ValueError;
  Compiler.IndexError = IndexError;


  // `CompilerError` is a general class of errors emitted by the Compiler.
  function CompilerError(message) {
    this.name = 'CompilerError';
    this.message = message;
  }
  CompilerError.prototype = Object.create(Error.prototype);
  CompilerError.prototype.constructor = CompilerError;

  // `CompilationError` extends `CompilerError`.  It's a class of errors 
  // which happen during compilation of the AST.
  function CompilationError(message, entry) {
    CompilerError.call(this, message);
    this.name = 'CompilationError';
    this.entry = entry.id;
  }
  CompilationError.prototype = Object.create(CompilerError.prototype);
  CompilationError.prototype.constructor = CompilationError;

  // `RuntimeError` extends `CompilerError`.  It's a class of errors which 
  // happen during the evaluation of entries, i.e. when you call 
  // `entity.toString()`.
  function RuntimeError(message) {
    CompilerError.call(this, message);
    this.name = 'RuntimeError';
  }
  RuntimeError.prototype = Object.create(CompilerError.prototype);
  RuntimeError.prototype.constructor = RuntimeError;

  // `ValueError` extends `RuntimeError`.  It's a class of errors which 
  // happen during the composition of a ComplexString value.  It's easier to 
  // recover from than an `IndexError` because at least we know that we're 
  // showing the correct member of the hash.
  function ValueError(message, entry, source) {
    RuntimeError.call(this, message);
    this.name = 'ValueError';
    this.entry = entry.id;
    this.source = source;
  }
  ValueError.prototype = Object.create(RuntimeError.prototype);
  ValueError.prototype.constructor = ValueError;

  // `IndexError` extends `RuntimeError`.  It's a class of errors which 
  // happen during the lookup of a hash member.  It's harder to recover 
  // from than `ValueError` because we en dup not knowing which variant of the 
  // entity value to show and in case the meanings are divergent, the 
  // consequences for the user can be serious.
  function IndexError(message, entry) {
    RuntimeError.call(this, message);
    this.name = 'IndexError';
    this.entry = entry.id;
  }
  IndexError.prototype = Object.create(RuntimeError.prototype);
  IndexError.prototype.constructor = IndexError;

  function requireCompilerError(e) {
    if (!(e instanceof CompilerError)) {
      throw e;
    }
  }

  exports.Compiler = Compiler;

});
define('l20n/retranslation', function(require, exports) {
  'use strict';

  function RetranslationManager() {
    var _usage = [];
    var _counter = {};
    var _callbacks = [];

    this.bindGet = bindGet;
    this.unbindGet = unbindGet;
    this.all = all;
    this.globals = {};

    RetranslationManager._constructors.forEach(function(ctor) {
      initGlobal.call(this, ctor);
    }, this);

    function initGlobal(GlobalCtor) {
      /* jshint validthis: true */
      var global = new GlobalCtor();
      this.globals[global.id] = global;
      if (!global.activate) {
        return;
      }
      _counter[global.id] = 0;
      global.addEventListener('change', function(id) {
        for (var i = 0; i < _usage.length; i++) {
          if (_usage[i] && _usage[i].globals.indexOf(id) !== -1) {
            // invoke the callback with the reason
            _usage[i].callback({
              global: global.id
            });
          }
        }
      });
    }

    function bindGet(get, isRebind) {
      /* jshint validthis: true */
      var i;
      // store the callback in case we want to retranslate the whole context
      var inCallbacks;
      for (i = 0; i < _callbacks.length; i++) {
        if (_callbacks[i].id === get.id) {
          inCallbacks = true;
          break;
        }
      }
      if (!inCallbacks) {
        _callbacks.push(get);
      } else if (isRebind) {
        _callbacks[i] = get;
      }

      // handle the global usage
      var bound;
      for (i = 0; i < _usage.length; i++) {
        if (_usage[i] && _usage[i].id === get.id) {
          bound = _usage[i];
          break;
        }
      }

      var added;
      if (!bound) {
        // it's the first time we see this get
        if (get.globals.length !== 0) {
          _usage.push(get);
          get.globals.forEach(function(id) {
            if (!this.globals[id].activate) {
              return;
            }
            _counter[id]++;
            this.globals[id].activate();
          }, this);
        }
      } else if (isRebind) {
        // if we rebinding the callback, don't remove globals
        // because we're just adding new entities to the bind
        bound.callback = get.callback;
        added = get.globals.filter(function(id) {
          return this.globals[id].activate && bound.globals.indexOf(id) === -1;
        }, this);
        added.forEach(function(id) {
          _counter[id]++;
          this.globals[id].activate();
        }, this);
        bound.globals = bound.globals.concat(added);
      } else if (get.globals.length === 0) {
        // after a retranslation, no globals were used; remove the callback
        delete _usage[i];
      } else {
        // see which globals were added and which ones were removed
        added = get.globals.filter(function(id) {
          return this.globals[id].activate && bound.globals.indexOf(id) === -1;
        }, this);
        added.forEach(function(id) {
          _counter[id]++;
          this.globals[id].activate();
        }, this);
        var removed = bound.globals.filter(function(id) {
          return this.globals[id].activate && get.globals.indexOf(id) === -1;
        }, this);
        removed.forEach(function(id) {
          _counter[id]--;
          if (_counter[id] === 0) {
            this.globals[id].deactivate();
          }
        }, this);
        bound.globals = get.globals;
      }
    }

    function unbindGet(id) {
      /* jshint validthis: true */
      var bound;
      var usagePos = -1;
      for (var i = 0; i < _usage.length; i++) {
        if (_usage[i] && _usage[i].id === id) {
          bound = _usage[i];
          usagePos = i;
          break;
        }
      }
      if (bound) {
        bound.globals.forEach(function(id) {
          if (this.globals[id].activate) {
            _counter[id]--;
            if (_counter[id] === 0) {
              this.globals[id].deactivate();
            }
          }
        }, this);
        _usage.splice(usagePos, 1);
        for (i = 0; i < _callbacks.length; i++) {
          if (_callbacks[i].id === id) {
            _callbacks.splice(i, 1);
            break;
          }
        }
      }
    }

    function all(locales) {
      for (var i = 0; i < _callbacks.length; i++) {
        // invoke the callback with the reason
        _callbacks[i].callback({
          locales: locales
        });
      }
    }
  }

  RetranslationManager._constructors = [];

  RetranslationManager.registerGlobal = function(ctor) {
    RetranslationManager._constructors.push(ctor);
  };

  RetranslationManager.deregisterGlobal = function(ctor) {
    var pos = RetranslationManager._constructors.indexOf(ctor);
    if (pos !== -1) {
      RetranslationManager._constructors.splice(pos, 1);
    }
  };

  exports.RetranslationManager = RetranslationManager;

});
define('l20n/platform/globals', function(require, exports) {
  'use strict';

  var EventEmitter = require('../events').EventEmitter;
  var RetranslationManager = require('../retranslation').RetranslationManager;

  function Global() {
    this.id = null;
    this._emitter = new EventEmitter();
    this.value = null;
    this.isActive = false;
  }

  Global.prototype._get = function _get() {
    throw new Error('Not implemented');
  };

  Global.prototype.get = function get() {
    // invalidate the cached value if the global is not active;  active 
    // globals handle `value` automatically in `onchange()`
    if (!this.value || !this.isActive) {
      this.value = this._get();
    }
    return this.value;
  };

  Global.prototype.addEventListener = function(type, listener) {
    if (type !== 'change') {
      throw 'Unknown event type';
    }
    this._emitter.addEventListener(type, listener);
  };


  // XXX: https://bugzilla.mozilla.org/show_bug.cgi?id=865226
  // We want to have @screen.width, but since we can't get it from compiler, we 
  // call it @screen and in order to keep API forward-compatible with 1.0 we 
  // return an object with key width to
  // make it callable as @screen.width
  function ScreenGlobal() {
    Global.call(this);
    this.id = 'screen';
    this._get = _get;

    this.activate = function activate() {
      if (!this.isActive) {
        window.addEventListener('resize', onchange);
        this.isActive = true;
      }
    };

    this.deactivate = function deactivate() {
      window.removeEventListener('resize', onchange);
      this.value = null;
      this.isActive = false;
    };

    function _get() {
      return {
        width: {
          px: document.body.clientWidth
        }
      };
    }

    var self = this;

    function onchange() {
      self.value = _get();
      self._emitter.emit('change', self.id);
    }
  }

  ScreenGlobal.prototype = Object.create(Global.prototype);
  ScreenGlobal.prototype.constructor = ScreenGlobal;


  function OSGlobal() {
    Global.call(this);
    this.id = 'os';
    this.get = get;

    function get() {
      if (/^MacIntel/.test(navigator.platform)) {
        return 'mac';
      }
      if (/^Linux/.test(navigator.platform)) {
        return 'linux';
      }
      if (/^Win/.test(navigator.platform)) {
        return 'win';
      }
      return 'unknown';
    }

  }

  OSGlobal.prototype = Object.create(Global.prototype);
  OSGlobal.prototype.constructor = OSGlobal;

  function HourGlobal() {
    Global.call(this);
    this.id = 'hour';
    this._get = _get;

    this.activate = function activate() {
      if (!this.isActive) {
        var time = new Date();
        I = setTimeout(function() {
          onchange();
          I = setInterval(onchange, interval);
        }, interval - (time.getTime() % interval));
        this.isActive = true;
      }
    };

    this.deactivate = function deactivate() {
      clearInterval(I);
      this.value = null;
      this.isActive = false;
    };

    function _get() {
      var time = new Date();
      return time.getHours();
    }

    var self = this;
    var interval = 60 * 60 * 1000;
    var I = null;



    function onchange() {
      var time = new Date();
      if (time.getHours() !== self.value) {
        self.value = time.getHours();
        self._emitter.emit('change', self.id);
      }
    }
  }

  HourGlobal.prototype = Object.create(Global.prototype);
  HourGlobal.prototype.constructor = HourGlobal;

  RetranslationManager.registerGlobal(ScreenGlobal);
  RetranslationManager.registerGlobal(OSGlobal);
  RetranslationManager.registerGlobal(HourGlobal);

  exports.Global = Global;

});
define('l20n/platform/io', function(require, exports) {
  'use strict';

  exports.load = function load(url, callback, sync) {
    var xhr = new XMLHttpRequest();
    if (xhr.overrideMimeType) {
      xhr.overrideMimeType('text/plain');
    }
    xhr.onreadystatechange = function() {
      if (xhr.readyState === 4) {
        if (xhr.status === 200 || xhr.status === 0) {
          callback(null, xhr.responseText);
        } else {
          var ex = new IOError('Not found: ' + url);
          callback(ex);
        }
      }
    };
    xhr.open('GET', url, !sync);
    xhr.send('');
  };

  function IOError(message) {
    this.name = 'IOError';
    this.message = message;
  }
  IOError.prototype = Object.create(Error.prototype);
  IOError.prototype.constructor = IOError;

  exports.Error = IOError;

});
define('l20n/intl', function(require, exports, module) {
  'use strict';

  if (!String.prototype.startsWith) {
    Object.defineProperty(String.prototype, 'startsWith', {
      enumerable: false,
      configurable: false,
      writable: false,
      value: function (searchString, position) {
        position = position || 0;
        return this.indexOf(searchString, position) === position;
      }
    });
  }

  var unicodeLocaleExtensionSequence = "-u(-[a-z0-9]{2,8})+";
  var unicodeLocaleExtensionSequenceRE = new RegExp(unicodeLocaleExtensionSequence);
  var unicodeLocaleExtensionSequenceGlobalRE = new RegExp(unicodeLocaleExtensionSequence, "g");
  var langTagMappings = {};
  var langSubtagMappings = {};
  var extlangMappings = {};

  /**
   * Regular expression defining BCP 47 language tags.
   *
   * Spec: RFC 5646 section 2.1.
   */
  var languageTagRE = (function () {
    // RFC 5234 section B.1
    // ALPHA          =  %x41-5A / %x61-7A   ; A-Z / a-z
    var ALPHA = "[a-zA-Z]";
    // DIGIT          =  %x30-39
    //                        ; 0-9
    var DIGIT = "[0-9]";

    // RFC 5646 section 2.1
    // alphanum      = (ALPHA / DIGIT)     ; letters and numbers
    var alphanum = "(?:" + ALPHA + "|" + DIGIT + ")";
    // regular       = "art-lojban"        ; these tags match the 'langtag'
    //               / "cel-gaulish"       ; production, but their subtags
    //               / "no-bok"            ; are not extended language
    //               / "no-nyn"            ; or variant subtags: their meaning
    //               / "zh-guoyu"          ; is defined by their registration
    //               / "zh-hakka"          ; and all of these are deprecated
    //               / "zh-min"            ; in favor of a more modern
    //               / "zh-min-nan"        ; subtag or sequence of subtags
    //               / "zh-xiang"
    var regular = "(?:art-lojban|cel-gaulish|no-bok|no-nyn|zh-guoyu|zh-hakka|zh-min|zh-min-nan|zh-xiang)";
    // irregular     = "en-GB-oed"         ; irregular tags do not match
    //                / "i-ami"             ; the 'langtag' production and
    //                / "i-bnn"             ; would not otherwise be
    //                / "i-default"         ; considered 'well-formed'
    //                / "i-enochian"        ; These tags are all valid,
    //                / "i-hak"             ; but most are deprecated
    //                / "i-klingon"         ; in favor of more modern
    //                / "i-lux"             ; subtags or subtag
    //                / "i-mingo"           ; combination
    //                / "i-navajo"
    //                / "i-pwn"
    //                / "i-tao"
    //                / "i-tay"
    //                / "i-tsu"
    //                / "sgn-BE-FR"
    //                / "sgn-BE-NL"
    //                / "sgn-CH-DE"
    var irregular = "(?:en-GB-oed|i-ami|i-bnn|i-default|i-enochian|i-hak|i-klingon|i-lux|i-mingo|i-navajo|i-pwn|i-tao|i-tay|i-tsu|sgn-BE-FR|sgn-BE-NL|sgn-CH-DE)";
    // grandfathered = irregular           ; non-redundant tags registered
    //               / regular             ; during the RFC 3066 era
    var grandfathered = "(?:" + irregular + "|" + regular + ")";
    // privateuse    = "x" 1*("-" (1*8alphanum))
    var privateuse = "(?:x(?:-[a-z0-9]{1,8})+)";
    // singleton     = DIGIT               ; 0 - 9
    //               / %x41-57             ; A - W
    //               / %x59-5A             ; Y - Z
    //               / %x61-77             ; a - w
    //               / %x79-7A             ; y - z
    var singleton = "(?:" + DIGIT + "|[A-WY-Za-wy-z])";
    // extension     = singleton 1*("-" (2*8alphanum))
    var extension = "(?:" + singleton + "(?:-" + alphanum + "{2,8})+)";
    // variant       = 5*8alphanum         ; registered variants
    //               / (DIGIT 3alphanum)
    var variant = "(?:" + alphanum + "{5,8}|(?:" + DIGIT + alphanum + "{3}))";
    // region        = 2ALPHA              ; ISO 3166-1 code
    //               / 3DIGIT              ; UN M.49 code
    var region = "(?:" + ALPHA + "{2}|" + DIGIT + "{3})";
    // script        = 4ALPHA              ; ISO 15924 code
    var script = "(?:" + ALPHA + "{4})";
    // extlang       = 3ALPHA              ; selected ISO 639 codes
    //                 *2("-" 3ALPHA)      ; permanently reserved
    var extlang = "(?:" + ALPHA + "{3}(?:-" + ALPHA + "{3}){0,2})";
    // language      = 2*3ALPHA            ; shortest ISO 639 code
    //                 ["-" extlang]       ; sometimes followed by
    //                                     ; extended language subtags
    //               / 4ALPHA              ; or reserved for future use
    //               / 5*8ALPHA            ; or registered language subtag
    var language = "(?:" + ALPHA + "{2,3}(?:-" + extlang + ")?|" + ALPHA + "{4}|" + ALPHA + "{5,8})";
    // langtag       = language
    //                 ["-" script]
    //                 ["-" region]
    //                 *("-" variant)
    //                 *("-" extension)
    //                 ["-" privateuse]
    var langtag = language + "(?:-" + script + ")?(?:-" + region + ")?(?:-" +
      variant + ")*(?:-" + extension + ")*(?:-" + privateuse + ")?";
    // Language-Tag  = langtag             ; normal language tags
    //               / privateuse          ; private use tag
    //               / grandfathered       ; grandfathered tags
    var languageTag = "^(?:" + langtag + "|" + privateuse + "|" + grandfathered + ")$";

    // Language tags are case insensitive (RFC 5646 section 2.1.1).
    return new RegExp(languageTag, "i");
  }());

  var duplicateVariantRE = (function () {
    // RFC 5234 section B.1
    // ALPHA          =  %x41-5A / %x61-7A   ; A-Z / a-z
    var ALPHA = "[a-zA-Z]";
    // DIGIT          =  %x30-39
    //                        ; 0-9
    var DIGIT = "[0-9]";

    // RFC 5646 section 2.1
    // alphanum      = (ALPHA / DIGIT)     ; letters and numbers
    var alphanum = "(?:" + ALPHA + "|" + DIGIT + ")";
    // variant       = 5*8alphanum         ; registered variants
    //               / (DIGIT 3alphanum)
    var variant = "(?:" + alphanum + "{5,8}|(?:" + DIGIT + alphanum + "{3}))";

    // Match a langtag that contains a duplicate variant.
    var duplicateVariant =
    // Match everything in a langtag prior to any variants, and maybe some
    // of the variants as well (which makes this pattern inefficient but
    // not wrong, for our purposes);
    "(?:" + alphanum + "{2,8}-)+" +
    // a variant, parenthesised so that we can refer back to it later;
    "(" + variant + ")-" +
    // zero or more subtags at least two characters long (thus stopping
    // before extension and privateuse components);
    "(?:" + alphanum + "{2,8}-)*" +
    // and the same variant again
    "\\1" +
    // ...but not followed by any characters that would turn it into a
    // different subtag.
    "(?!" + alphanum + ")";

  // Language tags are case insensitive (RFC 5646 section 2.1.1), but for
  // this regular expression that's covered by having its character classes
  // list both upper- and lower-case characters.
  return new RegExp(duplicateVariant);
  }());


  var duplicateSingletonRE = (function () {
    // RFC 5234 section B.1
    // ALPHA          =  %x41-5A / %x61-7A   ; A-Z / a-z
    var ALPHA = "[a-zA-Z]";
    // DIGIT          =  %x30-39
    //                        ; 0-9
    var DIGIT = "[0-9]";

    // RFC 5646 section 2.1
    // alphanum      = (ALPHA / DIGIT)     ; letters and numbers
    var alphanum = "(?:" + ALPHA + "|" + DIGIT + ")";
    // singleton     = DIGIT               ; 0 - 9
    //               / %x41-57             ; A - W
    //               / %x59-5A             ; Y - Z
    //               / %x61-77             ; a - w
    //               / %x79-7A             ; y - z
    var singleton = "(?:" + DIGIT + "|[A-WY-Za-wy-z])";

    // Match a langtag that contains a duplicate singleton.
    var duplicateSingleton =
    // Match a singleton subtag, parenthesised so that we can refer back to
    // it later;
      "-(" + singleton + ")-" +
      // then zero or more subtags;
      "(?:" + alphanum + "+-)*" +
      // and the same singleton again
      "\\1" +
      // ...but not followed by any characters that would turn it into a
      // different subtag.
      "(?!" + alphanum + ")";

  // Language tags are case insensitive (RFC 5646 section 2.1.1), but for
  // this regular expression that's covered by having its character classes
  // list both upper- and lower-case characters.
  return new RegExp(duplicateSingleton);
  }());

  /**
   * Verifies that the given string is a well-formed BCP 47 language tag
   * with no duplicate variant or singleton subtags.
   *
   * Spec: ECMAScript Internationalization API Specification, 6.2.2.
   */
  function IsStructurallyValidLanguageTag(locale) {
    if (!languageTagRE.test(locale))
      return false;

    // Before checking for duplicate variant or singleton subtags with
    // regular expressions, we have to get private use subtag sequences
    // out of the picture.
    if (locale.startsWith("x-"))
      return true;
    var pos = locale.indexOf("-x-");
    if (pos !== -1)
      locale = locale.substring(0, pos);

    // Check for duplicate variant or singleton subtags.
    return !duplicateVariantRE.test(locale) &&
      !duplicateSingletonRE.test(locale);
  }

  /**
   * Canonicalizes the given structurally valid BCP 47 language tag, including
   * regularized case of subtags. For example, the language tag
   * Zh-NAN-haNS-bu-variant2-Variant1-u-ca-chinese-t-Zh-laTN-x-PRIVATE, where
   *
   *     Zh             ; 2*3ALPHA
   *     -NAN           ; ["-" extlang]
   *     -haNS          ; ["-" script]
   *     -bu            ; ["-" region]
   *     -variant2      ; *("-" variant)
   *     -Variant1
   *     -u-ca-chinese  ; *("-" extension)
   *     -t-Zh-laTN
   *     -x-PRIVATE     ; ["-" privateuse]
   *
   * becomes nan-Hans-mm-variant2-variant1-t-zh-latn-u-ca-chinese-x-private
   *
   * Spec: ECMAScript Internationalization API Specification, 6.2.3.
   * Spec: RFC 5646, section 4.5.
   */
  function CanonicalizeLanguageTag(locale) {
    // The input
    // "Zh-NAN-haNS-bu-variant2-Variant1-u-ca-chinese-t-Zh-laTN-x-PRIVATE"
    // will be used throughout this method to illustrate how it works.

    // Language tags are compared and processed case-insensitively, so
    // technically it's not necessary to adjust case. But for easier processing,
    // and because the canonical form for most subtags is lower case, we start
    // with lower case for all.
    // "Zh-NAN-haNS-bu-variant2-Variant1-u-ca-chinese-t-Zh-laTN-x-PRIVATE" ->
    // "zh-nan-hans-bu-variant2-variant1-u-ca-chinese-t-zh-latn-x-private"
    locale = locale.toLowerCase();

    // Handle mappings for complete tags.
    if (langTagMappings && langTagMappings.hasOwnProperty(locale))
      return langTagMappings[locale];

    var subtags = locale.split("-");
    var i = 0;

    // Handle the standard part: All subtags before the first singleton or "x".
    // "zh-nan-hans-bu-variant2-variant1"
    while (i < subtags.length) {
      var subtag = subtags[i];

      // If we reach the start of an extension sequence or private use part,
      // we're done with this loop. We have to check for i > 0 because for
      // irregular language tags, such as i-klingon, the single-character
      // subtag "i" is not the start of an extension sequence.
      // In the example, we break at "u".
      if (subtag.length === 1 && (i > 0 || subtag === "x"))
        break;

      if (subtag.length === 4) {
        // 4-character subtags are script codes; their first character
        // needs to be capitalized. "hans" -> "Hans"
        subtag = subtag[0].toUpperCase() +
          subtag.substring(1);
      } else if (i !== 0 && subtag.length === 2) {
        // 2-character subtags that are not in initial position are region
        // codes; they need to be upper case. "bu" -> "BU"
        subtag = subtag.toUpperCase();
      }
      if (langSubtagMappings.hasOwnProperty(subtag)) {
        // Replace deprecated subtags with their preferred values.
        // "BU" -> "MM"
        // This has to come after we capitalize region codes because
        // otherwise some language and region codes could be confused.
        // For example, "in" is an obsolete language code for Indonesian,
        // but "IN" is the country code for India.
        // Note that the script generating langSubtagMappings makes sure
        // that no regular subtag mapping will replace an extlang code.
        subtag = langSubtagMappings[subtag];
      } else if (extlangMappings.hasOwnProperty(subtag)) {
        // Replace deprecated extlang subtags with their preferred values,
        // and remove the preceding subtag if it's a redundant prefix.
        // "zh-nan" -> "nan"
        // Note that the script generating extlangMappings makes sure that
        // no extlang mapping will replace a normal language code.
        subtag = extlangMappings[subtag].preferred;
        if (i === 1 && extlangMappings[subtag].prefix === subtags[0]) {
          subtags.shift();
          i--;
        }
      }
      subtags[i] = subtag;
      i++;
    }
    var normal = subtags.slice(0, i).join("-");

    // Extension sequences are sorted by their singleton characters.
    // "u-ca-chinese-t-zh-latn" -> "t-zh-latn-u-ca-chinese"
    var extensions = [];
    while (i < subtags.length && subtags[i] !== "x") {
      var extensionStart = i;
      i++;
      while (i < subtags.length && subtags[i].length > 1)
        i++;
      var extension = sybtags.slice(extensionStart, i).join("-");
      extensions.push(extension);
    }
    extensions.sort();

    // Private use sequences are left as is. "x-private"
    var privateUse = "";
    if (i < subtags.length)
      privateUse = subtags.slice(i).join("-");

    // Put everything back together.
    var canonical = normal;
    if (extensions.length > 0)
      canonical += "-" + extensions.join("-");
    if (privateUse.length > 0) {
      // Be careful of a Language-Tag that is entirely privateuse.
      if (canonical.length > 0)
        canonical += "-" + privateUse;
      else
        canonical = privateUse;
    }

    return canonical;
  }

  /**
   * Canonicalizes a locale list.
   *
   * Spec: ECMAScript Internationalization API Specification, 9.2.1.
   */
  function CanonicalizeLocaleList(locales) {
    if (locales === undefined)
      return [];
    var seen = [];
    if (typeof locales === "string")
      locales = [locales];
    var O = locales;
    var len = O.length;
    var k = 0;
    while (k < len) {
      // Don't call ToString(k) - SpiderMonkey is faster with integers.
      var kPresent = k in O;
      if (kPresent) {
        var kValue = O[k];
        if (!(typeof kValue === "string" || typeof kValue === "object"))
          ThrowError(JSMSG_INVALID_LOCALES_ELEMENT);
        var tag = kValue;
        if (!IsStructurallyValidLanguageTag(tag))
          ThrowError(JSMSG_INVALID_LANGUAGE_TAG, tag);
        tag = CanonicalizeLanguageTag(tag);
        if (seen.indexOf(tag) === -1)
          seen.push(tag);
      }
      k++;
    }
    return seen;
  }

  /**
   * Compares a BCP 47 language tag against the locales in availableLocales
   * and returns the best available match. Uses the fallback
   * mechanism of RFC 4647, section 3.4.
   *
   * Spec: ECMAScript Internationalization API Specification, 9.2.2.
   * Spec: RFC 4647, section 3.4.
   */
  function BestAvailableLocale(availableLocales, locale) {
    var candidate = locale;
    while (true) {
      if (availableLocales.indexOf(candidate) !== -1)
        return candidate;
      var pos = candidate.lastIndexOf('-');
      if (pos === -1)
        return undefined;
      if (pos >= 2 && candidate[pos - 2] === "-")
        pos -= 2;
      candidate = candidate.substring(0, pos);
    }
  }

  /**
   * Returns the subset of availableLocales for which requestedLocales has a
   * matching (possibly fallback) locale. Locales appear in the same order in the
   * returned list as in the input list.
   *
   * This function is a slight modification of the LookupSupprtedLocales algorithm
   * The difference is in step 4d where instead of adding requested locale,
   * we're adding availableLocale to the subset.
   *
   * This allows us to directly use returned subset to pool resources.
   *
   * Spec: ECMAScript Internationalization API Specification, 9.2.6.
   */
  function LookupAvailableLocales(availableLocales, requestedLocales) {
    // Steps 1-2.
    var len = requestedLocales.length;
    var subset = [];

    // Steps 3-4.
    var k = 0;
    while (k < len) {
      // Steps 4.a-b.
      var locale = requestedLocales[k];
      var noExtensionsLocale = locale.replace(unicodeLocaleExtensionSequenceGlobalRE, "");

      // Step 4.c-d.
      var availableLocale = BestAvailableLocale(availableLocales, noExtensionsLocale);
      if (availableLocale !== undefined)
        // in LookupSupportedLocales it pushes locale here
        subset.push(availableLocale);

      // Step 4.e.
      k++;
    }

    // Steps 5-6.
    return subset.slice(0);
  }

  function PrioritizeLocales(availableLocales,
                             requestedLocales,
                             defaultLocale) {
    availableLocales = CanonicalizeLocaleList(availableLocales);
    requestedLocales = CanonicalizeLocaleList(requestedLocales);

    var result = LookupAvailableLocales(availableLocales, requestedLocales);
    if (!defaultLocale) {
      return result;
    }

    // if default locale is not present in result,
    // add it to the end of fallback chain
    defaultLocale = CanonicalizeLanguageTag(defaultLocale);
    if (result.indexOf(defaultLocale) === -1) {
      result.push(defaultLocale);
    }
    return result;
  }

  exports.Intl = {
    prioritizeLocales: PrioritizeLocales
  };

});
// attach the L20n singleton to the global object
window.L20n = require('l20n');

// hook up the HTML bindings
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// close the function defined in build/prefix/microrequire.js
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