Fix all the things. And break most of the other things, in all likelihood.

46 files changed, 1812 insertions, 1521 deletions

diff --git a/common/content/abbreviations.js b/common/content/abbreviations.js
index f81b35a3..a3e351e8 100644
--- a/common/content/abbreviations.js
+++ b/common/content/abbreviations.js
@@ -116,7 +116,7 @@ var AbbrevHive = Class("AbbrevHive", Contexts.Hive, {
         if (!(abbr instanceof Abbreviation))
             abbr = Abbreviation.apply(null, arguments);
 
-        for (let [, mode] in Iterator(abbr.modes)) {
+        for (let mode of abbr.modes) {
             if (!this._store[mode])
                 this._store[mode] = {};
             this._store[mode][abbr.lhs] = abbr;
@@ -156,7 +156,7 @@ var AbbrevHive = Class("AbbrevHive", Contexts.Hive, {
      */
     remove: function (modes, lhs) {
         let result = false;
-        for (let [, mode] in Iterator(modes)) {
+        for (let mode of modes) {
             if ((mode in this._store) && (lhs in this._store[mode])) {
                 result = true;
                 this._store[mode][lhs].removeMode(mode);
@@ -172,8 +172,8 @@ var AbbrevHive = Class("AbbrevHive", Contexts.Hive, {
      * @param {Array} modes List of modes.
      */
     clear: function (modes) {
-        for (let mode in values(modes)) {
-            for (let abbr in values(this._store[mode]))
+        for (let mode of values(modes)) {
+            for (let abbr of values(this._store[mode]))
                 abbr.removeMode(mode);
             delete this._store[mode];
         }
@@ -276,15 +276,18 @@ var Abbreviations = Module("abbreviations", {
                     ["td", { style: "padding-right: 1em;" }, _("title.Abbrev")],
                     ["td", { style: "padding-right: 1em;" }, _("title.Replacement")]],
                 ["col", { style: "min-width: 6em; padding-right: 1em;" }],
-                hives.map(hive => let (i = 0) [
-                    ["tr", { style: "height: .5ex;" }],
-                    abbrevs(hive).map(abbrev =>
-                        ["tr", {},
-                            ["td", { highlight: "Title" }, !i++ ? String(hive.name) : ""],
-                            ["td", {}, abbrev.modeChar],
-                            ["td", {}, abbrev.lhs],
-                            ["td", {}, abbrev.rhs]]),
-                    ["tr", { style: "height: .5ex;" }]])];
+                hives.map(hive => {
+                    let i = 0;
+                    return [
+                        ["tr", { style: "height: .5ex;" }],
+                        abbrevs(hive).map(abbrev =>
+                            ["tr", {},
+                                ["td", { highlight: "Title" }, !i++ ? String(hive.name) : ""],
+                                ["td", {}, abbrev.modeChar],
+                                ["td", {}, abbrev.lhs],
+                                ["td", {}, abbrev.rhs]]),
+                        ["tr", { style: "height: .5ex;" }]];
+                })];
 
         // FIXME?
         // // TODO: Move this to an ItemList to show this automatically
@@ -361,7 +364,7 @@ var Abbreviations = Module("abbreviations", {
                                     "-javascript": callable(abbr.rhs) ? null : undefined
                                 }
                             }
-                            for ([, abbr] in Iterator(hive.merged))
+                            for (abbr of hive.merged)
                             if (abbr.modesEqual(modes))
                         ]).
                         flatten().array
diff --git a/common/content/autocommands.js b/common/content/autocommands.js
index 73cdd20c..7451689a 100644
--- a/common/content/autocommands.js
+++ b/common/content/autocommands.js
@@ -23,7 +23,7 @@ var AutoCmdHive = Class("AutoCmdHive", Contexts.Hive, {
         this._store = [];
     },
 
-    __iterator__: function () array.iterValues(this._store),
+    "@@iterator": function () array.iterValues(this._store),
 
     /**
      * Adds a new autocommand. *cmd* will be executed when one of the specified
@@ -38,7 +38,7 @@ var AutoCmdHive = Class("AutoCmdHive", Contexts.Hive, {
         if (!callable(pattern))
             pattern = Group.compileFilter(pattern);
 
-        for (let event in values(events))
+        for (let event of values(events))
             this._store.push(AutoCommand(event, pattern, cmd));
     },
 
@@ -134,7 +134,7 @@ var AutoCommands = Module("autocommands", {
         if (options.get("eventignore").has(event))
             return;
 
-        dactyl.echomsg(_("autocmd.executing", event, "*".quote()), 8);
+        dactyl.echomsg(_("autocmd.executing", event, '"*"'), 8);
 
         let lastPattern = null;
         var { url, doc } = args;
@@ -144,10 +144,10 @@ var AutoCommands = Module("autocommands", {
             var { uri, doc } = buffer;
 
         event = event.toLowerCase();
-        for (let hive in values(this.matchingHives(uri, doc))) {
+        for (let hive of values(this.matchingHives(uri, doc))) {
             let args = hive.makeArgs(doc, null, arguments[1]);
 
-            for (let autoCmd in values(hive._store))
+            for (let autoCmd of values(hive._store))
                 if (autoCmd.eventName === event && autoCmd.filter(uri, doc)) {
                     if (!lastPattern || lastPattern !== String(autoCmd.filter))
                         dactyl.echomsg(_("autocmd.executing", event, autoCmd.filter), 8);
diff --git a/common/content/bookmarks.js b/common/content/bookmarks.js
index 1754ac05..c755a6bf 100644
--- a/common/content/bookmarks.js
+++ b/common/content/bookmarks.js
@@ -76,7 +76,7 @@ var Bookmarks = Module("bookmarks", {
             if (keyword && hasOwnProperty(bookmarkcache.keywords, keyword))
                 bmark = bookmarkcache.keywords[keyword];
             else if (bookmarkcache.isBookmarked(uri))
-                for (bmark in bookmarkcache)
+                for (bmark of bookmarkcache)
                     if (bmark.url == uri.spec)
                         break;
         }
@@ -421,11 +421,11 @@ var Bookmarks = Module("bookmarks", {
             return dactyl.open(items.map(i => i.url), dactyl.NEW_TAB);
 
         if (filter.length > 0 && tags.length > 0)
-            dactyl.echoerr(_("bookmark.noMatching", tags.map(String.quote), filter.quote()));
+            dactyl.echoerr(_("bookmark.noMatching", tags.map(JSON.stringify), JSON.stringify(filter)));
         else if (filter.length > 0)
-            dactyl.echoerr(_("bookmark.noMatchingString", filter.quote()));
+            dactyl.echoerr(_("bookmark.noMatchingString", JSON.stringify(filter)));
         else if (tags.length > 0)
-            dactyl.echoerr(_("bookmark.noMatchingTags", tags.map(String.quote)));
+            dactyl.echoerr(_("bookmark.noMatchingTags", tags.map(JSON.stringify)));
         else
             dactyl.echoerr(_("bookmark.none"));
         return null;
@@ -455,7 +455,7 @@ var Bookmarks = Module("bookmarks", {
                 if (!args.bang)
                     return [
                         [win.document.title, frames.length == 1 ? /*L*/"Current Location" : /*L*/"Frame: " + win.location.href]
-                        for ([, win] in Iterator(frames))];
+                        for (win of frames)];
                 context.keys.text = "title";
                 context.keys.description = "url";
                 return bookmarks.get(args.join(" "), args["-tags"], null, { keyword: args["-keyword"], title: context.filter });
@@ -519,7 +519,7 @@ var Bookmarks = Module("bookmarks", {
                         let frames = buffer.allFrames();
                         context.completions = [
                             [win.document.documentURI, frames.length == 1 ? /*L*/"Current Location" : /*L*/"Frame: " + win.document.title]
-                            for ([, win] in Iterator(frames))];
+                            for (win of frames)];
                         return;
                     }
                     completion.bookmark(context, args["-tags"], { keyword: args["-keyword"], title: args["-title"] });
@@ -695,7 +695,7 @@ var Bookmarks = Module("bookmarks", {
                     context.generate = function () {
                         let [begin, end] = item.url.split("%s");
 
-                        let seen = RealSet();
+                        let seen = new RealSet;
                         return history.get({ uri: util.newURI(begin), uriIsPrefix: true }).map(function (item) {
                             let rest = item.url.length - end.length;
                             let query = item.url.substring(begin.length, rest);
diff --git a/common/content/browser.js b/common/content/browser.js
index 2db10105..4641d61d 100644
--- a/common/content/browser.js
+++ b/common/content/browser.js
@@ -160,7 +160,7 @@ var Browser = Module("browser", XPCOM(Ci.nsISupportsWeakReference, ModuleBase),
                 let oldURI = overlay.getData(win.document)["uri"];
                 if (overlay.getData(win.document)["load-idx"] === webProgress.loadedTransIndex
                     || !oldURI || uri.spec.replace(/#.*/, "") !== oldURI.replace(/#.*/, ""))
-                    for (let frame in values(buffer.allFrames(win)))
+                    for (let frame of values(buffer.allFrames(win)))
                         overlay.setData(frame.document, "focus-allowed", false);
 
                 overlay.setData(win.document, "uri", uri.spec);
diff --git a/common/content/commandline.js b/common/content/commandline.js
index 9cc34a02..f876e413 100644
--- a/common/content/commandline.js
+++ b/common/content/commandline.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -231,13 +231,13 @@ var CommandWidgets = Class("CommandWidgets", {
 
     updateVisibility: function updateVisibility() {
         let changed = 0;
-        for (let elem in values(this.elements))
+        for (let elem of values(this.elements))
             if (elem.getGroup) {
                 let value = elem.getValue ? elem.getValue.call(this)
                           : elem.noValue || this[elem.name];
 
                 let activeGroup = this.getGroup(elem.name, value);
-                for (let group in values([this.commandbar, this.statusbar])) {
+                for (let group of [this.commandbar, this.statusbar]) {
                     let meth, node = group[elem.name];
                     let visible = (value && group === activeGroup);
                     if (node && !node.collapsed == !visible) {
@@ -277,7 +277,7 @@ var CommandWidgets = Class("CommandWidgets", {
                ["viewable", "complete"].indexOf(elem.contentDocument.readyState) >= 0;
     },
 
-    _whenReady: function _whenReady(id, init) {
+    _whenReady: function* _whenReady(id, init) {
         let elem = document.getElementById(id);
         while (!this._ready(elem))
             yield 10;
@@ -502,11 +502,11 @@ var CommandLine = Module("commandline", {
 
         memoize(this, "_store", function () storage.newMap("command-history", { store: true, privateData: true }));
 
-        for (let name in values(["command", "search"]))
+        for (let name of ["command", "search"])
             if (storage.exists("history-" + name)) {
                 let ary = storage.newArray("history-" + name, { store: true, privateData: true });
 
-                this._store.set(name, [v for ([k, v] in ary)]);
+                this._store.set(name, [v for ([k, v] of ary)]);
                 ary.delete();
                 this._store.changed();
             }
@@ -632,7 +632,7 @@ var CommandLine = Module("commandline", {
     },
 
     hideCompletions: function hideCompletions() {
-        for (let nodeSet in values([this.widgets.statusbar, this.widgets.commandbar]))
+        for (let nodeSet of values([this.widgets.statusbar, this.widgets.commandbar]))
             if (nodeSet.commandline.completionList)
                 nodeSet.commandline.completionList.visible = false;
     },
@@ -1882,7 +1882,7 @@ var CommandLine = Module("commandline", {
             persistent: true,
             action: function (timespan, host) {
                 let store = commandline._store;
-                for (let [k, v] in store) {
+                for (let [k, v] of store) {
                     if (k == "command")
                         store.set(k, v.filter(item =>
                             !(timespan.contains(item.timestamp) && (!host || commands.hasDomain(item.value, host)))));
@@ -1974,8 +1974,11 @@ var ItemList = Class("ItemList", {
                            .filter(c => c.items.length || c.message || c.incomplete)
                            .map(this.getGroup, this),
 
-    get selected() let (g = this.selectedGroup) g && g.selectedIdx != null
-        ? [g.context, g.selectedIdx] : null,
+    get selected() {
+        let g = this.selectedGroup;
+        return g && g.selectedIdx != null ? [g.context, g.selectedIdx]
+                                           : null;
+    },
 
     getRelativeItem: function getRelativeItem(offset, tuple, noWrap) {
         let groups = this.activeGroups;
@@ -2021,7 +2024,11 @@ var ItemList = Class("ItemList", {
         if (start < 0 || start >= this.itemCount)
             return null;
 
-        group = groups.find(g => let (i = start - g.offsets.start) i >= 0 && i < g.itemCount);
+        group = groups.find(g => {
+            let i = start - g.offsets.start;
+            return i >= 0 && i < g.itemCount;
+        });
+
         return [group.context, start - group.offsets.start];
     },
 
@@ -2075,7 +2082,7 @@ var ItemList = Class("ItemList", {
     updateOffsets: function updateOffsets() {
         let total = this.itemCount;
         let count = 0;
-        for (let group in values(this.activeGroups)) {
+        for (let group of values(this.activeGroups)) {
             group.offsets = { start: count, end: total - count - group.itemCount };
             count += group.itemCount;
         }
@@ -2090,7 +2097,7 @@ var ItemList = Class("ItemList", {
 
         let container = DOM(this.nodes.completions);
         let groups = this.activeGroups;
-        for (let group in values(groups)) {
+        for (let group of values(groups)) {
             group.reset();
             container.append(group.nodes.root);
         }
@@ -2133,7 +2140,7 @@ var ItemList = Class("ItemList", {
      * @private
      */
     draw: function draw() {
-        for (let group in values(this.activeGroups))
+        for (let group of values(this.activeGroups))
             group.draw();
 
         // We need to collect all of the rescrolling functions in
@@ -2244,7 +2251,7 @@ var ItemList = Class("ItemList", {
             }
 
             let count = this.maxItems;
-            for (let group in values(groups)) {
+            for (let group of groups) {
                 let off = Math.max(0, start - group.offsets.start);
 
                 group.count = Math.constrain(group.itemCount - off, 0, count);
@@ -2379,7 +2386,7 @@ var ItemList = Class("ItemList", {
 
             if (!this.generatedRange.contains(this.range)) {
                 if (this.generatedRange.end == 0)
-                    var [start, end] = this.range;
+                    var [start, end] = Array.slice(this.range);
                 else {
                     start = this.range.start - (this.range.start <= this.generatedRange.start
                                                     ? this.maxItems / 2 : 0);
@@ -2391,19 +2398,20 @@ var ItemList = Class("ItemList", {
                                            Math.min(this.itemCount, end));
 
                 let first;
-                for (let [i, row] in this.context.getRows(this.generatedRange.start,
+                for (let [i, row] of this.context.getRows(this.generatedRange.start,
                                                           this.generatedRange.end,
-                                                          this.doc))
+                                                          this.doc)) {
                     if (!range.contains(i))
                         DOM(row).remove();
                     else if (!first)
                         first = row;
+                }
 
                 let container = DOM(this.nodes.items);
                 let before    = first ? DOM(first).bound.before
                                       : DOM(this.nodes.items).bound.append;
 
-                for (let [i, row] in this.context.getRows(range.start, range.end,
+                for (let [i, row] of this.context.getRows(range.start, range.end,
                                                           this.doc)) {
                     if (i < this.generatedRange.start)
                         before(row);
diff --git a/common/content/dactyl.js b/common/content/dactyl.js
index a9f93574..f98c9692 100644
--- a/common/content/dactyl.js
+++ b/common/content/dactyl.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -47,7 +47,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
     },
 
     cleanup: function () {
-        for (let cleanup in values(this.cleanups))
+        for (let cleanup of values(this.cleanups))
             cleanup.call(this);
 
         delete window.dactyl;
@@ -73,7 +73,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
     // has :set go= or something similar in his config
     hideGUI: function () {
         let guioptions = config.guioptions;
-        for (let option in guioptions) {
+        for (let option of guioptions) {
             guioptions[option].forEach(function (elem) {
                 try {
                     document.getElementById(elem).collapsed = true;
@@ -87,7 +87,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
         "dactyl-cleanup": function dactyl_cleanup(subject, reason) {
             let modules = dactyl.modules;
 
-            for (let mod in values(modules.moduleList.reverse())) {
+            for (let mod of values(modules.moduleList.reverse())) {
                 mod.stale = true;
                 if ("cleanup" in mod)
                     this.trapErrors("cleanup", mod, reason);
@@ -97,7 +97,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
 
             modules.moduleManager.initDependencies("cleanup");
 
-            for (let name in values(Object.getOwnPropertyNames(modules).reverse()))
+            for (let name of values(Object.getOwnPropertyNames(modules).reverse()))
                 try {
                     delete modules[name];
                 }
@@ -131,7 +131,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             if (~["menu", "menupopup"].indexOf(node.localName) && node.children.length)
                 DOM(node).popupshowing({ bubbles: false });
 
-            for (let [, item] in Iterator(node.childNodes)) {
+            for (let item of node.childNodes) {
                 if (item.childNodes.length == 0 && item.localName == "menuitem"
                     && !item.hidden
                     && !/rdf:http:/.test(item.getAttribute("label"))) { // FIXME
@@ -169,7 +169,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
     get forceOpen() ({ background: this.forceBackground,
                        target: this.forceTarget }),
     set forceOpen(val) {
-        for (let [k, v] in Iterator({ background: "forceBackground", target: "forceTarget" }))
+        for (let [k, v] of iter({ background: "forceBackground", target: "forceTarget" }))
             if (k in val)
                 this[v] = val[k];
     },
@@ -205,7 +205,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
     },
 
     registerObservers: function registerObservers(obj, prop) {
-        for (let [signal, func] in Iterator(obj[prop || "signals"]))
+        for (let [signal, func] of iter(obj[prop || "signals"]))
             this.registerObserver(signal, func.bind(obj), false);
     },
 
@@ -238,8 +238,11 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                 let results = array(params.iterate(args))
                     .sort((a, b) => String.localeCompare(a.name, b.name));
 
-                let filters = args.map(arg => let (re = util.regexp.escape(arg))
-                                        util.regexp("\\b" + re + "\\b|(?:^|[()\\s])" + re + "(?:$|[()\\s])", "i"));
+                let filters = args.map(arg => {
+                    let re = util.regexp.escape(arg);
+                    return util.regexp("\\b" + re + "\\b|(?:^|[()\\s])" + re + "(?:$|[()\\s])", "i");
+                });
+
                 if (filters.length)
                     results = results.filter(item => filters.every(re => keys(item).some(re.bound.test)));
 
@@ -254,7 +257,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                     context.ignoreCase = true;
                     let seen = {};
                     context.completions = array(keys(item).join(" ").toLowerCase().split(/[()\s]+/)
-                                                for (item in params.iterate(args)))
+                                                for (item of params.iterate(args)))
                         .flatten()
                         .map(function (k) {
                             seen[k] = (seen[k] || 0) + 1;
@@ -265,11 +268,11 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             });
 
         if (params.index)
-            this.indices[params.index] = function () {
+            this.indices[params.index] = function* () {
                 let results = array((params.iterateIndex || params.iterate).call(params, commands.get(name).newArgs()))
                         .array.sort((a, b) => String.localeCompare(a.name, b.name));
 
-                for (let obj in values(results)) {
+                for (let obj of values(results)) {
                     let res = dactyl.generateHelp(obj, null, null, true);
                     if (!hasOwnProperty(help.tags, obj.helpTag))
                         res[0][1].tag = obj.helpTag;
@@ -536,7 +539,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
         if (!silent)
             commands.lastCommand = str.replace(/^\s*:\s*/, "");
         let res = true;
-        for (let [command, args] in commands.parseCommands(str.replace(/^'(.*)'$/, "$1"))) {
+        for (let [command, args] of commands.parseCommands(str.replace(/^'(.*)'$/, "$1"))) {
             if (command === null)
                 throw FailedAssertion(_("dactyl.notCommand", config.appName, args.commandString));
 
@@ -667,10 +670,12 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
         else if (obj instanceof Map) {
             spec = map => (obj.count ? [["oa", {}, "count"], map]
                                      : DOM.DOMString(map));
-            tag = map => [
-                let (c = obj.modes[0].char) c ? c + "_" : "",
-                map
-            ];
+            tag = map => {
+                let c = obj.modes[0].char;
+                return [c ? c + "_" : "",
+                        map];
+            };
+
             link = map => {
                 let [, mode, name, extra] = /^(?:(.)_)?(?:<([^>]+)>)?(.*)$/.exec(map);
                 let k = ["k", {}, extra];
@@ -700,17 +705,16 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             extraHelp ? extraHelp : "",
             !(extraHelp || obj.description) ? ["p", {}, /*L*/ "Sorry, no help available."] : ""];
 
+        let name = (obj.specs || obj.names)[0];
         res.push(
             ["item", {},
                 ["tags", {}, template.map(obj.names.slice().reverse(),
                                           tag,
                                           " ").join("")],
-                ["spec", {},
-                    let (name = (obj.specs || obj.names)[0])
-                          spec(template.highlightRegexp(tag(name),
-                               /\[(.*?)\]/g,
-                               (m, n0) => ["oa", {}, n0]),
-                               name)],
+                ["spec", {}, spec(template.highlightRegexp(tag(name),
+                                                           /\[(.*?)\]/g,
+                                                           (m, n0) => ["oa", {}, n0]),
+                                  name)],
                 !obj.type ? "" : [
                     ["type", {}, obj.type],
                     ["default", {}, obj.stringDefaultValue]],
@@ -790,13 +794,14 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
 
         dactyl.echomsg(
             _("plugin.searchingForIn",
-                ("plugins/**/*.{js," + config.fileExtension + "}").quote(),
-                [dir.path.replace(/.plugins$/, "") for ([, dir] in Iterator(dirs))]
-                    .join(",").quote()),
+                JSON.stringify("plugins/**/*.{js," + config.fileExtension + "}"),
+                JSON.stringify([dir.path.replace(/.plugins$/, "")
+                               for (dir of dirs)]
+                                   .join(","))),
             2);
 
         dirs.forEach(function (dir) {
-            dactyl.echomsg(_("plugin.searchingFor", (dir.path + "/**/*.{js," + config.fileExtension + "}").quote()), 3);
+            dactyl.echomsg(_("plugin.searchingFor", JSON.stringify(dir.path + "/**/*.{js," + config.fileExtension + "}")), 3);
             sourceDirectory(dir);
         });
     },
@@ -909,7 +914,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             params = { where: params };
 
         let flags = 0;
-        for (let [opt, flag] in Iterator({ replace: "REPLACE_HISTORY", hide: "BYPASS_HISTORY" }))
+        for (let [opt, flag] of iter({ replace: "REPLACE_HISTORY", hide: "BYPASS_HISTORY" }))
             flags |= params[opt] && Ci.nsIWebNavigation["LOAD_FLAGS_" + flag];
 
         let where = params.where || dactyl.CURRENT_TAB;
@@ -1220,7 +1225,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             // Process plugin help entries.
 
             let body = [];
-            for (let [, context] in Iterator(plugins.contexts))
+            for (let context of values(plugins.contexts))
                 try {
                     let info = contexts.getDocs(context);
                     if (DOM.isJSONXML(info)) {
@@ -1371,7 +1376,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                     N: ["Tab number over icon", highlight.selector("TabIconNumber")]
                 },
                 setter: function (opts) {
-                    let classes = [v[1] for ([k, v] in Iterator(this.opts)) if (opts.indexOf(k) < 0)];
+                    let classes = [v[1] for ([k, v] of iter(this.opts)) if (opts.indexOf(k) < 0)];
 
                     styles.system.add("taboptions", "chrome://*",
                                       classes.length ? classes.join(",") + "{ display: none; }" : "");
@@ -1392,14 +1397,14 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
 
                 // FIXME: cleanup
                 cleanupValue: config.cleanups.guioptions ||
-                    "rb" + [k for ([k, v] in iter(groups[1].opts))
+                    "rb" + [k for ([k, v] of iter(groups[1].opts))
                             if (!Dactyl.toolbarHidden(document.getElementById(v[1][0])))].join(""),
 
-                values: array(groups).map(g => [[k, v[0]] for ([k, v] in Iterator(g.opts))])
+                values: array(groups).map(g => [[k, v[0]] for ([k, v] of iter(g.opts))])
                                      .flatten(),
 
                 setter: function (value) {
-                    for (let group in values(groups))
+                    for (let group of values(groups))
                         group.setter(value);
                     events.checkFocus();
                     return value;
@@ -1494,7 +1499,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                     config.dialogs[dialog][1]();
                 }
                 catch (e) {
-                    dactyl.echoerr(_("error.cantOpen", dialog.quote(), e.message || e));
+                    dactyl.echoerr(_("error.cantOpen", JSON.stringify(dialog), e.message || e));
                 }
             }, {
                 argCount: "1",
@@ -1513,7 +1518,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                 dactyl.assert(items.some(i => i.dactylPath == arg),
                               _("emenu.notFound", arg));
 
-                for (let [, item] in Iterator(items)) {
+                for (let item of items) {
                     if (item.dactylPath == arg) {
                         dactyl.assert(!item.disabled, _("error.disabled", item.dactylPath));
                         item.doCommand();
@@ -1716,7 +1721,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                         let each, eachUnits, totalUnits;
                         let total = 0;
 
-                        for (let i in util.interruptibleRange(0, count, 500)) {
+                        for (let i of util.interruptibleRange(0, count, 500)) {
                             let now = Date.now();
                             func();
                             total += Date.now() - now;
@@ -1843,7 +1848,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
         completion.dialog = function dialog(context) {
             context.title = ["Dialog"];
             context.filters.push(({ item }) => !item[2] || item[2]());
-            context.completions = [[k, v[0], v[2]] for ([k, v] in Iterator(config.dialogs))];
+            context.completions = [[k, v[0], v[2]] for ([k, v] of iter(config.dialogs))];
         };
 
         completion.menuItem = function menuItem(context) {
@@ -1988,7 +1993,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             // after sourcing the initialization files, this function will set
             // all gui options to their default values, if they have not been
             // set before by any RC file
-            for (let option in values(options.needInit))
+            for (let option of values(options.needInit))
                 option.initValue();
 
             if (dactyl.commandLineOptions.postCommands)
diff --git a/common/content/editor.js b/common/content/editor.js
index 0bad993c..8344b7ed 100644
--- a/common/content/editor.js
+++ b/common/content/editor.js
@@ -245,7 +245,7 @@ var Editor = Module("editor", XPCOM(Ci.nsIEditActionListener, ModuleBase), {
                                           range[container]);
 
             let delta = 0;
-            for (let node in Editor.TextsIterator(range)) {
+            for (let node of Editor.TextsIterator(range)) {
                 let text = node.textContent;
                 let start = 0, end = text.length;
                 if (node == range.startContainer)
@@ -427,7 +427,7 @@ var Editor = Module("editor", XPCOM(Ci.nsIEditActionListener, ModuleBase), {
         column = 1 + pre.replace(/[^]*\n/, "").length;
 
         let origGroup = DOM(textBox).highlight.toString();
-        let cleanup = promises.task(function cleanup(error) {
+        let cleanup = promises.task(function* cleanup(error) {
             if (timer)
                 timer.cancel();
 
@@ -447,7 +447,7 @@ var Editor = Module("editor", XPCOM(Ci.nsIEditActionListener, ModuleBase), {
                 if (!keepFocus)
                     dactyl.focus(textBox);
 
-                for (let group in values(blink.concat(blink, ""))) {
+                for (let group of values(blink.concat(blink, ""))) {
                     highlight.highlightNode(textBox, origGroup + " " + group);
 
                     yield promises.sleep(100);
@@ -548,7 +548,7 @@ var Editor = Module("editor", XPCOM(Ci.nsIEditActionListener, ModuleBase), {
             this.range = range;
         },
 
-        __iterator__: function __iterator__() {
+        "@@iterator": function* __iterator__() {
             while (this.nextNode())
                 yield this.context;
         },
@@ -1122,14 +1122,15 @@ var Editor = Module("editor", XPCOM(Ci.nsIEditActionListener, ModuleBase), {
         bind(["<C-t>"], "Edit text field in Text Edit mode",
              function () {
                  dactyl.assert(!editor.isTextEdit && editor.editor);
-                 dactyl.assert(dactyl.focusedElement ||
-                               // Sites like Google like to use a
-                               // hidden, editable window for keyboard
-                               // focus and use their own WYSIWYG editor
-                               // implementations for the visible area,
-                               // which we can't handle.
-                               let (f = document.commandDispatcher.focusedWindow.frameElement)
-                                    f && Hints.isVisible(f, true));
+                 if (!dactyl.focusedElement) {
+                     // Sites like Google like to use a
+                     // hidden, editable window for keyboard
+                     // focus and use their own WYSIWYG editor
+                     // implementations for the visible area,
+                     // which we can't handle.
+                     let f = document.commandDispatcher.focusedWindow.frameElement;
+                     dactyl.assert(f && Hints.isVisible(f, true));
+                 }
 
                  modes.push(modes.TEXT_EDIT);
              });
@@ -1371,7 +1372,7 @@ var Editor = Module("editor", XPCOM(Ci.nsIEditActionListener, ModuleBase), {
                 has: function (key) util.compileMacro(this.value).seen.has(key),
                 validator: function (value) {
                     this.format({}, value);
-                    let allowed = RealSet(["column", "file", "line"]);
+                    let allowed = new RealSet(["column", "file", "line"]);
                     return [k for (k of util.compileMacro(value).seen)]
                                 .every(k => allowed.has(k));
                 }
@@ -1409,7 +1410,7 @@ var Editor = Module("editor", XPCOM(Ci.nsIEditActionListener, ModuleBase), {
             persistent: true,
             action: function (timespan, host) {
                 if (!host) {
-                    for (let [k, v] in editor.registers)
+                    for (let [k, v] of editor.registers)
                         if (timespan.contains(v.timestamp))
                             editor.registers.remove(k);
                     editor.registerRing.truncate(0);
diff --git a/common/content/events.js b/common/content/events.js
index 844a5b51..80599821 100644
--- a/common/content/events.js
+++ b/common/content/events.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -49,7 +49,7 @@ var EventHive = Class("EventHive", Contexts.Hive, {
     listen: function (target, event, callback, capture, allowUntrusted) {
         var [self, events] = this._events(event, callback);
 
-        for (let [event, callback] in Iterator(events)) {
+        for (let [event, callback] of iter(events)) {
             let args = [util.weakReference(target),
                         util.weakReference(self),
                         event,
@@ -119,7 +119,7 @@ var Events = Module("events", {
 
         this._macros = storage.newMap("registers", { privateData: true, store: true });
         if (storage.exists("macros")) {
-            for (let [k, m] in storage.newMap("macros", { store: true }))
+            for (let [k, m] of storage.newMap("macros", { store: true }))
                 this._macros.set(k, { text: m.keys, timestamp: m.timeRecorded * 1000 });
             storage.remove("macros");
         }
@@ -308,7 +308,7 @@ var Events = Module("events", {
      */
     getMacros: function (filter) {
         let re = RegExp(filter || "");
-        return ([k, m.text] for ([k, m] in editor.registers) if (re.test(k)));
+        return ([k, m.text] for ([k, m] of editor.registers) if (re.test(k)));
     },
 
     /**
@@ -319,7 +319,7 @@ var Events = Module("events", {
      */
     deleteMacros: function (filter) {
         let re = RegExp(filter || "");
-        for (let [item, ] in editor.registers) {
+        for (let [item, ] of editor.registers) {
             if (!filter || re.test(item))
                 editor.registers.remove(item);
         }
@@ -373,10 +373,10 @@ var Events = Module("events", {
             if (quiet)
                 commandline.quiet = quiet;
 
-            for (let [, evt_obj] in Iterator(DOM.Event.parse(keys))) {
+            for (let evt_obj of DOM.Event.parse(keys)) {
                 let now = Date.now();
                 let key = DOM.Event.stringify(evt_obj);
-                for (let type in values(["keydown", "keypress", "keyup"])) {
+                for (let type of values(["keydown", "keypress", "keyup"])) {
                     let evt = update({}, evt_obj, { type: type });
                     if (type !== "keypress" && !evt.keyCode)
                         evt.keyCode = evt._keyCode || 0;
@@ -475,13 +475,13 @@ var Events = Module("events", {
                         .toObject();
 
     outer:
-        for (let [, key] in iter(elements))
+        for (let [, key] of iter(elements))
             if (filters.some(([k, v]) => key.getAttribute(k) == v)) {
                 let keys = { ctrlKey: false, altKey: false, shiftKey: false, metaKey: false };
                 let needed = { ctrlKey: event.ctrlKey, altKey: event.altKey, shiftKey: event.shiftKey, metaKey: event.metaKey };
 
                 let modifiers = (key.getAttribute("modifiers") || "").trim().split(/[\s,]+/);
-                for (let modifier in values(modifiers))
+                for (let modifier of values(modifiers))
                     switch (modifier) {
                     case "access": update(keys, access); break;
                     case "accel":  keys[accel] = true; break;
@@ -489,7 +489,7 @@ var Events = Module("events", {
                     case "any":
                         if (!iter.some(keys, ([k, v]) => v && needed[k]))
                             continue outer;
-                        for (let [k, v] in iter(keys)) {
+                        for (let [k, v] of iter(keys)) {
                             if (v)
                                 needed[k] = false;
                             keys[k] = false;
@@ -677,7 +677,7 @@ var Events = Module("events", {
                 let ourEvent = DOM.Event.feedingEvent;
                 DOM.Event.feedingEvent = null;
                 if (ourEvent)
-                    for (let [k, v] in Iterator(ourEvent))
+                    for (let [k, v] of iter(ourEvent))
                         if (!(k in event))
                             event[k] = v;
 
@@ -781,7 +781,7 @@ var Events = Module("events", {
                 if (this.feedingKeys)
                     this.duringFeed = this.duringFeed.concat(duringFeed);
                 else
-                    for (let event in values(duringFeed))
+                    for (let event of values(duringFeed))
                         try {
                             DOM.Event.dispatch(event.originalTarget, event, event);
                         }
@@ -797,6 +797,8 @@ var Events = Module("events", {
             else if (!this.processor)
                 this.keyEvents = [];
 
+            let key = DOM.Event.stringify(event);
+
             let pass = this.passing && !event.isMacro ||
                     DOM.Event.feedingEvent && DOM.Event.feedingEvent.isReplay ||
                     event.isReplay ||
@@ -807,14 +809,13 @@ var Events = Module("events", {
                     !modes.passThrough && this.shouldPass(event) ||
                     !this.processor && event.type === "keydown"
                         && options.get("passunknown").getKey(modes.main.allBases)
-                        && let (key = DOM.Event.stringify(event))
-                            !(modes.main.count && /^\d$/.test(key) ||
-                              modes.main.allBases.some(
-                                mode => mappings.hives
-                                                .some(hive => hive.get(mode, key)
-                                                           || hive.getCandidates(mode, key))));
-
-            events.dbg("ON " + event.type.toUpperCase() + " " + DOM.Event.stringify(event) +
+                        && !(modes.main.count && /^\d$/.test(key) ||
+                             modes.main.allBases.some(
+                               mode => mappings.hives
+                                               .some(hive => hive.get(mode, key)
+                                                          || hive.getCandidates(mode, key))));
+
+            events.dbg("ON " + event.type.toUpperCase() + " " + key +
                        " passing: " + this.passing + " " +
                        " pass: " + pass +
                        " replay: " + event.isReplay +
@@ -924,12 +925,18 @@ var Events = Module("events", {
             if (elem == null && urlbar && urlbar.inputField == this._lastFocus.get())
                 util.threadYield(true); // Why? --Kris
 
-            while (modes.main.ownsFocus
-                    && let ({ ownsFocus } = modes.topOfStack.params)
-                         (!ownsFocus ||
-                             ownsFocus.get() != elem &&
-                             ownsFocus.get() != win)
-                    && !modes.topOfStack.params.holdFocus)
+            let ownsFocus = () => {
+                if (!modes.main.ownsFocus)
+                    return false;
+
+                let { ownsFocus } = modes.topOfStack.params;
+                if (ownsFocus && ~[elem, win].indexOf(ownsFocus.get()))
+                    return false;
+
+                return !modes.topOfStack.params.holdFocus;
+            };
+
+            while (ownsFocus())
                  modes.pop(null, { fromFocus: true });
         }
         finally {
@@ -966,9 +973,10 @@ var Events = Module("events", {
     PASS_THROUGH: {},
     WAIT: null,
 
-    isEscape: function isEscape(event)
-        let (key = isString(event) ? event : DOM.Event.stringify(event))
-            key === "<Esc>" || key === "<C-[>",
+    isEscape: function isEscape(event) {
+        let key = isString(event) ? event : DOM.Event.stringify(event);
+        return key === "<Esc>" || key === "<C-[>";
+    },
 
     isHidden: function isHidden(elem, aggressive) {
         if (DOM(elem).style.visibility !== "visible")
@@ -1033,7 +1041,7 @@ var Events = Module("events", {
     completion: function initCompletion() {
         completion.macro = function macro(context) {
             context.title = ["Macro", "Keys"];
-            context.completions = [item for (item in events.getMacros())];
+            context.completions = [item for (item of events.getMacros())];
         };
     },
     mappings: function initMappings() {
@@ -1140,7 +1148,7 @@ var Events = Module("events", {
             "sitemap", "", {
                 flush: function flush() {
                     memoize(this, "filters", function () this.value.filter(function (f) f(buffer.documentURI)));
-                    memoize(this, "pass", function () RealSet(array.flatten(this.filters.map(function (f) f.keys))));
+                    memoize(this, "pass", function () new RealSet(array.flatten(this.filters.map(function (f) f.keys))));
                     memoize(this, "commandHive", function hive() Hive(this.filters, "command"));
                     memoize(this, "inputHive", function hive() Hive(this.filters, "input"));
                 },
diff --git a/common/content/hints.js b/common/content/hints.js
index 4a39252a..781f06e5 100644
--- a/common/content/hints.js
+++ b/common/content/hints.js
@@ -179,7 +179,7 @@ var HintSession = Class("HintSession", CommandMode, {
     getHintNumber: function getHintNumber(str) {
         let base = this.hintKeys.length;
         let res = 0;
-        for (let char in values(str))
+        for (let char of values(str))
             res = res * base + this.hintKeys.indexOf(char);
         return res;
     },
@@ -286,7 +286,7 @@ var HintSession = Class("HintSession", CommandMode, {
 
         memoize(doc, "dactylLabels", () =>
             iter([l.getAttribute("for"), l]
-                 for (l in array.iterValues(doc.querySelectorAll("label[for]"))))
+                 for (l of array.iterValues(doc.querySelectorAll("label[for]"))))
              .toObject());
 
         let [offsetX, offsetY] = this.getContainerOffsets(doc);
@@ -330,7 +330,7 @@ var HintSession = Class("HintSession", CommandMode, {
 
             let start = this.pageHints.length;
             let _hints = [];
-            for (let elem in res)
+            for (let elem of res)
                 if (isVisible(elem) && (!mode.filter || mode.filter(elem)))
                     _hints.push({
                         elem: elem,
@@ -545,14 +545,14 @@ var HintSession = Class("HintSession", CommandMode, {
      *     hint disappears.
      */
     removeHints: function _removeHints(timeout) {
-        for (let { doc, start, end } in values(this.docs)) {
+        for (let { doc, start, end } of values(this.docs)) {
             DOM(doc.documentElement).highlight.remove("Hinting");
             // Goddamn stupid fucking Gecko 1.x security manager bullshit.
             try { delete doc.dactylLabels; } catch (e) { doc.dactylLabels = undefined; }
 
-            for (let elem in DOM.XPath("//*[@dactyl:highlight='hints']", doc))
+            for (let elem of DOM.XPath("//*[@dactyl:highlight='hints']", doc))
                 elem.parentNode.removeChild(elem);
-            for (let i in util.range(start, end + 1)) {
+            for (let i of util.range(start, end + 1)) {
                 this.pageHints[i].ambiguous = false;
                 this.pageHints[i].valid = false;
             }
@@ -590,12 +590,12 @@ var HintSession = Class("HintSession", CommandMode, {
         let activeHint = this.hintNumber || 1;
         this.validHints = [];
 
-        for (let { doc, start, end } in values(this.docs)) {
+        for (let { doc, start, end } of values(this.docs)) {
             DOM(doc.documentElement).highlight.add("Hinting");
             let [offsetX, offsetY] = this.getContainerOffsets(doc);
 
         inner:
-            for (let i in (util.interruptibleRange(start, end + 1, 500))) {
+            for (let i of util.interruptibleRange(start, end + 1, 500)) {
                 if (this.showCount != count)
                     return;
 
@@ -644,13 +644,13 @@ var HintSession = Class("HintSession", CommandMode, {
         }
 
         let base = this.hintKeys.length;
-        for (let [i, hint] in Iterator(this.validHints))
+        for (let [i, hint] of iter(this.validHints))
             hint.ambiguous = (i + 1) * base <= this.validHints.length;
 
         if (options["usermode"]) {
             let css = [];
-            for (let hint in values(this.pageHints)) {
-                let selector = highlight.selector("Hint") + "[number=" + hint.span.getAttribute("number").quote() + "]";
+            for (let hint of values(this.pageHints)) {
+                let selector = highlight.selector("Hint") + "[number=" + JSON.stringify(hint.span.getAttribute("number")) + "]";
                 let imgSpan = "[dactyl|hl=HintImage]";
                 css.push(selector + ":not(" + imgSpan + ") { " + hint.span.style.cssText + " }");
                 if (hint.imgSpan)
@@ -699,7 +699,7 @@ var HintSession = Class("HintSession", CommandMode, {
 
     updateValidNumbers: function updateValidNumbers(always) {
         let string = this.getHintString(this.hintNumber);
-        for (let hint in values(this.validHints))
+        for (let hint of values(this.validHints))
             hint.valid = always || hint.span.getAttribute("number").startsWith(string);
     },
 
@@ -866,7 +866,7 @@ var Hints = Module("hints", {
         if (DOM(elem).isInput)
             return [elem.value, false];
         else {
-            for (let [, option] in Iterator(options["hintinputs"])) {
+            for (let option of options["hintinputs"]) {
                 if (option == "value") {
                     if (elem instanceof Ci.nsIDOMHTMLSelectElement) {
                         if (elem.selectedIndex >= 0)
@@ -1022,7 +1022,7 @@ var Hints = Module("hints", {
              */
             function stringsAtBeginningOfWords(strings, words, allowWordOverleaping) {
                 let strIdx = 0;
-                for (let [, word] in Iterator(words)) {
+                for (let word of words) {
                     if (word.length == 0)
                         continue;
 
@@ -1077,7 +1077,8 @@ var Hints = Module("hints", {
             autocomplete: false,
             completer: function (context) {
                 context.compare = () => 0;
-                context.completions = [[k, v.prompt] for ([k, v] in Iterator(hints.modes))];
+                context.completions = [[k, v.prompt]
+                                       for ([k, v] of iter(hints.modes))];
             },
             onCancel: mappings.bound.popCommand,
             onSubmit: function (arg) {
@@ -1315,14 +1316,18 @@ var Hints = Module("hints", {
             {
                 keepQuotes: true,
 
-                getKey: function (val, default_)
-                    let (res = this.value.find(re => let (match = re.exec(val)) match && match[0] == val))
-                        res ? res.matcher
-                            : default_,
+                getKey: function (val, default_) {
+                    let res = this.value.find(re => {
+                        let match = re.exec(val);
+                        return match && match[0] == val;
+                    });
+                    return res ? res.matcher
+                               : default_;
+                },
 
                 parse: function parse(val) {
                     let vals = parse.supercall(this, val);
-                    for (let value in values(vals))
+                    for (let value of values(vals))
                         value.matcher = DOM.compileMatcher(Option.splitList(value.result));
                     return vals;
                 },
diff --git a/common/content/history.js b/common/content/history.js
index 5b2c6d3f..0e2883e6 100644
--- a/common/content/history.js
+++ b/common/content/history.js
@@ -21,7 +21,7 @@ var History = Module("history", {
         let query = services.history.getNewQuery();
         let options = services.history.getNewQueryOptions();
 
-        for (let [k, v] in Iterator(filter))
+        for (let [k, v] of iter(filter))
             query[k] = v;
 
         let res = /^([+-])(.+)/.exec(sort);
@@ -65,9 +65,9 @@ var History = Module("history", {
         let obj = [];
         obj.__defineGetter__("index", () => sh.index);
         obj.__defineSetter__("index", function (val) { webNav.gotoIndex(val); });
-        obj.__iterator__ = function () array.iterItems(this);
+        obj[Symbol.iterator] = function () array.iterItems(this);
 
-        for (let item in iter(sh.SHistoryEnumerator, Ci.nsISHEntry))
+        for (let item of iter(sh.SHistoryEnumerator, Ci.nsISHEntry))
             obj.push(update(Object.create(item), {
                 index: obj.length,
                 icon: Class.Memoize(function () services.favicon.getFaviconImageForPage(this.URI).spec)
@@ -166,7 +166,7 @@ var History = Module("history", {
             return dactyl.open(items.map(i => i.url), dactyl.NEW_TAB);
 
         if (filter.length > 0)
-            dactyl.echoerr(_("history.noMatching", filter.quote()));
+            dactyl.echoerr(_("history.noMatching", JSON.stringify(filter)));
         else
             dactyl.echoerr(_("history.none"));
         return null;
@@ -187,7 +187,7 @@ var History = Module("history", {
                         if (/^\d+(:|$)/.test(url) && sh.index - parseInt(url) in sh)
                             return void window.getWebNavigation().gotoIndex(sh.index - parseInt(url));
 
-                        for (let [i, ent] in Iterator(sh.slice(0, sh.index).reverse()))
+                        for (let [i, ent] of iter(sh.slice(0, sh.index).reverse()))
                             if (ent.URI.spec == url)
                                 return void window.getWebNavigation().gotoIndex(i);
                         dactyl.echoerr(_("history.noURL"));
@@ -229,7 +229,7 @@ var History = Module("history", {
                         if (/^\d+(:|$)/.test(url) && sh.index + parseInt(url) in sh)
                             return void window.getWebNavigation().gotoIndex(sh.index + parseInt(url));
 
-                        for (let [i, ent] in Iterator(sh.slice(sh.index + 1)))
+                        for (let [i, ent] of iter(sh.slice(sh.index + 1)))
                             if (ent.URI.spec == url)
                                 return void window.getWebNavigation().gotoIndex(i);
                         dactyl.echoerr(_("history.noURL"));
@@ -333,7 +333,7 @@ var History = Module("history", {
             // FIXME: Schema-specific
             context.generate = () => [
                 Array.slice(row.rev_host).reverse().join("").slice(1)
-                for (row in iter(services.history.DBConnection
+                for (row of iter(services.history.DBConnection
                                          .createStatement("SELECT DISTINCT rev_host FROM moz_places WHERE rev_host IS NOT NULL;")))
             ].slice(2);
         };
diff --git a/common/content/key-processors.js b/common/content/key-processors.js
index d1a51d21..5487d7cf 100644
--- a/common/content/key-processors.js
+++ b/common/content/key-processors.js
@@ -26,7 +26,7 @@ var ProcessorStack = Class("ProcessorStack", {
                                     .flatten().array;
         this.ownsBuffer = !this.processors.some(p => p.main.ownsBuffer);
 
-        for (let [i, input] in Iterator(this.processors)) {
+        for (let input of this.processors) {
             let params = input.main.params;
 
             if (params.preExecute)
@@ -82,7 +82,7 @@ var ProcessorStack = Class("ProcessorStack", {
             // those waiting on further arguments. Execute actions as
             // long as they continue to return PASS.
 
-            for (var action in values(this.actions)) {
+            for (var action of values(this.actions)) {
                 while (callable(action)) {
                     length = action.eventLength;
                     action = dactyl.trapErrors(action);
@@ -171,7 +171,7 @@ var ProcessorStack = Class("ProcessorStack", {
 
         events.dbg("PROCESS(" + key + ") skipmap: " + event.skipmap + " macro: " + event.isMacro + " replay: " + event.isReplay);
 
-        for (let [i, input] in Iterator(this.processors)) {
+        for (let input of this.processors) {
             let res = input.process(event);
             if (res !== Events.ABORT)
                 var result = res;
@@ -197,14 +197,14 @@ var ProcessorStack = Class("ProcessorStack", {
         this._actions = actions;
         this.actions = actions.concat(this.actions);
 
-        for (let action in values(actions))
+        for (let action of values(actions))
             if (!("eventLength" in action))
                 action.eventLength = this.events.length;
 
         if (result === Events.KILL)
             this.actions = [];
         else if (!this.actions.length && !processors.length)
-            for (let input in values(this.processors))
+            for (let input of values(this.processors))
                 if (input.fallthrough) {
                     if (result === Events.KILL)
                         break;
diff --git a/common/content/mappings.js b/common/content/mappings.js
index 5a1d6b26..11d73c9b 100644
--- a/common/content/mappings.js
+++ b/common/content/mappings.js
@@ -197,11 +197,11 @@ var MapHive = Class("MapHive", Contexts.Hive, {
         map.hive = this;
 
         if (this.name !== "builtin")
-            for (let [, name] in Iterator(map.names))
-                for (let [, mode] in Iterator(map.modes))
+            for (let name of map.names)
+                for (let mode of map.modes)
                     this.remove(mode, name);
 
-        for (let mode in values(map.modes))
+        for (let mode of values(map.modes))
             this.getStack(mode).add(map);
         return map;
     },
@@ -255,13 +255,13 @@ var MapHive = Class("MapHive", Contexts.Hive, {
      */
     remove: function (mode, cmd) {
         let stack = this.getStack(mode);
-        for (let [i, map] in array.iterItems(stack)) {
+        for (let map of stack) {
             let j = map.names.indexOf(cmd);
             if (j >= 0) {
                 delete stack.states;
                 map.names.splice(j, 1);
                 if (map.names.length == 0) // FIX ME.
-                    for (let [mode, stack] in Iterator(this.stacks))
+                    for (let [mode, stack] of iter(this.stacks))
                         this.stacks[mode] = MapHive.Stack(stack.filter(m => m != map));
                 return;
             }
@@ -284,7 +284,7 @@ var MapHive = Class("MapHive", Contexts.Hive, {
             return self;
         },
 
-        __iterator__: function () array.iterValues(this),
+        "@@iterator": function () array.iterValues(this),
 
         get candidates() this.states.candidates,
         get mappings() this.states.mappings,
@@ -300,11 +300,11 @@ var MapHive = Class("MapHive", Contexts.Hive, {
                 mappings: {}
             };
 
-            for (let map in this)
-                for (let name in values(map.keys)) {
+            for (let map of this)
+                for (let name of values(map.keys)) {
                     states.mappings[name] = map;
                     let state = "";
-                    for (let key in DOM.Event.iterKeys(name)) {
+                    for (let key of DOM.Event.iterKeys(name)) {
                         state += key;
                         if (state !== name)
                             states.candidates[state] = (states.candidates[state] || 0) + 1;
@@ -379,17 +379,17 @@ var Mappings = Module("mappings", {
         return keys;
     },
 
-    iterate: function (mode) {
-        let seen = RealSet();
-        for (let hive in this.hives.iterValues())
-            for (let map in array(hive.getStack(mode)).iterValues())
+    iterate: function* (mode) {
+        let seen = new RealSet;
+        for (let hive of this.hives.iterValues())
+            for (let map of array(hive.getStack(mode)).iterValues())
                 if (!seen.add(map.name))
                     yield map;
     },
 
     // NOTE: just normal mode for now
     /** @property {Iterator(Map)} */
-    __iterator__: function () this.iterate(modes.NORMAL),
+    "@@iterator": function () this.iterate(modes.NORMAL),
 
     getDefault: deprecated("mappings.builtin.get", function getDefault(mode, cmd) this.builtin.get(mode, cmd)),
     getUserIterator: deprecated("mappings.user.iterator", function getUserIterator(modes) this.user.iterator(modes)),
@@ -488,16 +488,19 @@ var Mappings = Module("mappings", {
                     ["td", { style: "padding-right: 1em;" }, _("title.Command")],
                     ["td", { style: "padding-right: 1em;" }, _("title.Action")]],
                 ["col", { style: "min-width: 6em; padding-right: 1em;" }],
-                hives.map(([hive, maps]) => let (i = 0) [
-                    ["tr", { style: "height: .5ex;" }],
-                    maps.map(map =>
-                        map.names.map(name =>
-                        ["tr", {},
-                            ["td", { highlight: "Title" }, !i++ ? hive.name : ""],
-                            ["td", {}, modeSign],
-                            ["td", {}, name],
-                            ["td", {}, map.rhs || map.action.toSource()]])),
-                    ["tr", { style: "height: .5ex;" }]])];
+                hives.map(([hive, maps]) => {
+                    let i = 0;
+                    return [
+                        ["tr", { style: "height: .5ex;" }],
+                        maps.map(map =>
+                            map.names.map(name =>
+                            ["tr", {},
+                                ["td", { highlight: "Title" }, !i++ ? hive.name : ""],
+                                ["td", {}, modeSign],
+                                ["td", {}, name],
+                                ["td", {}, map.rhs || map.action.toSource()]])),
+                        ["tr", { style: "height: .5ex;" }]];
+                })];
 
         // E4X-FIXME
         // // TODO: Move this to an ItemList to show this automatically
@@ -631,16 +634,16 @@ var Mappings = Module("mappings", {
                                     literalArg: map.rhs,
                                     ignoreDefaults: true
                                 }
-                                for (map in userMappings(hive))
+                                for (map of userMappings(hive))
                                 if (map.persist)
                             ])
                             .flatten().array;
                 }
             };
-            function userMappings(hive) {
-                let seen = RealSet();
-                for (let stack in values(hive.stacks))
-                    for (let map in array.iterValues(stack))
+            function* userMappings(hive) {
+                let seen = new RealSet;
+                for (let stack of values(hive.stacks))
+                    for (let map of array.iterValues(stack))
                         if (!seen.add(map.id))
                             yield map;
             }
@@ -666,7 +669,7 @@ var Mappings = Module("mappings", {
                     let mapmodes = array.uniq(args["-modes"].map(findMode));
 
                     let found = 0;
-                    for (let mode in values(mapmodes))
+                    for (let mode of values(mapmodes))
                         if (args.bang)
                             args["-group"].clear(mode);
                         else if (args["-group"].has(mode, args[0])) {
@@ -699,20 +702,20 @@ var Mappings = Module("mappings", {
             type: CommandOption.STRING,
             validator: function (value) Array.concat(value).every(findMode),
             completer: function () [[array.compact([mode.name.toLowerCase().replace(/_/g, "-"), mode.char]), mode.description]
-                                    for (mode in values(modes.all))
+                                    for (mode of values(modes.all))
                                     if (!mode.hidden)]
         };
 
         function findMode(name) {
             if (name)
-                for (let mode in values(modes.all))
+                for (let mode of values(modes.all))
                     if (name == mode || name == mode.char
                         || String.toLowerCase(name).replace(/-/g, "_") == mode.name.toLowerCase())
                         return mode;
             return null;
         }
         function uniqueModes(modes) {
-            let chars = [k for ([k, v] in Iterator(modules.modes.modeChars))
+            let chars = [k for ([k, v] of iter(modules.modes.modeChars))
                          if (v.every(mode => modes.indexOf(mode) >= 0))];
 
             return array.uniq(modes.filter(m => chars.indexOf(m.char) < 0)
@@ -736,25 +739,25 @@ var Mappings = Module("mappings", {
 
         addMapCommands("", [modes.NORMAL, modes.VISUAL], "");
 
-        for (let mode in modes.mainModes)
+        for (let mode of modes.mainModes)
             if (mode.char && !commands.get(mode.char + "map", true))
                 addMapCommands(mode.char,
-                               [m.mask for (m in modes.mainModes) if (m.char == mode.char)],
+                               [m.mask for (m of modes.mainModes) if (m.char == mode.char)],
                                mode.displayName);
 
         let args = {
             getMode: function (args) findMode(args["-mode"]),
-            iterate: function (args, mainOnly) {
+            iterate: function* (args, mainOnly) {
                 let modes = [this.getMode(args)];
                 if (!mainOnly)
                     modes = modes[0].allBases;
 
-                let seen = RealSet();
+                let seen = new RealSet;
                 // Bloody hell. --Kris
-                for (let [i, mode] in Iterator(modes))
-                    for (let hive in mappings.hives.iterValues())
-                        for (let map in array.iterValues(hive.getStack(mode)))
-                            for (let name in values(map.names))
+                for (let [i, mode] of iter(modes))
+                    for (let hive of mappings.hives.iterValues())
+                        for (let map of array.iterValues(hive.getStack(mode)))
+                            for (let name of values(map.names))
                                 if (!seen.add(name))
                                     yield {
                                         name: name,
@@ -775,8 +778,10 @@ var Mappings = Module("mappings", {
                             : [],
                         template.linkifyHelp(map.description + (map.rhs ? ": " + map.rhs : ""))
                 ],
-                help: function (map) let (char = array.compact(map.modes.map(m => m.char))[0])
-                    char === "n" ? map.name : char ? char + "_" + map.name : "",
+                help: function (map) {
+                    let char = array.compact(map.modes.map(m => m.char))[0];
+                    return char === "n" ? map.name : char ? char + "_" + map.name : "";
+                },
                 headings: ["Command", "Mode", "Group", "Description"]
             }
         };
@@ -798,12 +803,15 @@ var Mappings = Module("mappings", {
                 dactyl.addUsageCommand({
                     __proto__: args,
                     name: [mode.char + "listk[eys]", mode.char + "lk"],
-                    iterateIndex: function (args)
-                            let (self = this, prefix = /^[bCmn]$/.test(mode.char) ? "" : mode.char + "_",
-                                 haveTag = k => hasOwnProperty(help.tags, k))
-                                    ({ helpTag: prefix + map.name, __proto__: map }
-                                     for (map in self.iterate(args, true))
-                                     if (map.hive === mappings.builtin || haveTag(prefix + map.name))),
+                    iterateIndex: function (args) {
+                        let self = this;
+                        let prefix = /^[bCmn]$/.test(mode.char) ? "" : mode.char + "_";
+                        let haveTag = k => hasOwnProperty(help.tags, k);
+
+                        return ({ helpTag: prefix + map.name, __proto__: map }
+                                for (map of self.iterate(args, true))
+                                if (map.hive === mappings.builtin || haveTag(prefix + map.name)));
+                    },
                     description: "List all " + mode.displayName + " mode mappings along with their short descriptions",
                     index: mode.char + "-map",
                     getMode: function (args) mode,
@@ -823,7 +831,7 @@ var Mappings = Module("mappings", {
             [
                 null,
                 function (context, obj, args) [[m.names, m.description]
-                                               for (m in this.iterate(args[0]))]
+                                               for (m of this.iterate(args[0]))]
             ]);
     },
     mappings: function initMappings(dactyl, modules, window) {
diff --git a/common/content/marks.js b/common/content/marks.js
index 7f6e256e..2d87bb50 100644
--- a/common/content/marks.js
+++ b/common/content/marks.js
@@ -181,7 +181,7 @@ var Marks = Module("marks", {
 
             let tab = mark.tab && mark.tab.get();
             if (!tab || !tab.linkedBrowser || tabs.allTabs.indexOf(tab) == -1)
-                for ([, tab] in iter(tabs.visibleTabs, tabs.allTabs)) {
+                for ([, tab] of iter(tabs.visibleTabs, tabs.allTabs)) {
                     if (tab.linkedBrowser.contentDocument.documentURI.replace(/#.*/, "") === mark.location)
                         break;
                     tab = null;
@@ -205,7 +205,7 @@ var Marks = Module("marks", {
                     a.length = b.length = Math.max(a.length, b.length);
                     items = array(a).zip(b).flatten().compact();
 
-                    for (let i in items.iterValues()) {
+                    for (let i of items.iterValues()) {
                         let entry = sh.getEntryAtIndex(i, false);
                         if (entry.URI.spec.replace(/#.*/, "") == mark.location)
                             return void tab.linkedBrowser.webNavigation.gotoIndex(i);
@@ -234,7 +234,7 @@ var Marks = Module("marks", {
         if (!mark.path)
             var node = buffer.findScrollable(0, (mark.offset || mark.position).x);
         else
-            for (node in DOM.XPath(mark.path, buffer.focusedFrame.document))
+            for (node of DOM.XPath(mark.path, buffer.focusedFrame.document))
                 break;
 
         util.assert(node);
@@ -260,7 +260,7 @@ var Marks = Module("marks", {
         if (filter.length > 0) {
             let pattern = util.charListToRegexp(filter, "a-zA-Z");
             marks = marks.filter(([k]) => (pattern.test(k)));
-            dactyl.assert(marks.length > 0, _("mark.noMatching", filter.quote()));
+            dactyl.assert(marks.length > 0, _("mark.noMatching", JSON.stringify(filter)));
         }
 
         commandline.commandOutput(
@@ -273,7 +273,7 @@ var Marks = Module("marks", {
                   mark.offset ? Math.round(mark.offset.y)
                               : Math.round(mark.position.y * 100) + "%",
                   mark.location]
-                  for ([, [name, mark]] in Iterator(marks)))));
+                  for ([name, mark] of marks))));
     },
 
     _onPageLoad: function _onPageLoad(event) {
@@ -388,18 +388,20 @@ var Marks = Module("marks", {
             contains: ["history"],
             action: function (timespan, host) {
                 function matchhost(url) !host || util.isDomainURL(url, host);
-                function match(marks) (k for ([k, v] in Iterator(marks)) if (timespan.contains(v.timestamp) && matchhost(v.location)));
+                function match(marks) (k
+                                       for ([k, v] in iter(marks))
+                                       if (timespan.contains(v.timestamp) && matchhost(v.location)));
 
-                for (let [url, local] in marks._localMarks)
+                for (let [url, local] of marks._localMarks)
                     if (matchhost(url)) {
-                        for (let key in match(local))
+                        for (let key of match(local))
                             delete local[key];
                         if (!Object.keys(local).length)
                             marks._localMarks.remove(url);
                     }
                 marks._localMarks.changed();
 
-                for (let key in match(marks._urlMarks))
+                for (let key of match(marks._urlMarks))
                     marks._urlMarks.remove(key);
             }
         });
diff --git a/common/content/modes.js b/common/content/modes.js
index d4cd2739..bd534030 100644
--- a/common/content/modes.js
+++ b/common/content/modes.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -150,7 +150,7 @@ var Modes = Module("modes", {
                     dactyl.focusContent(true);
                 if (prev.main == modes.NORMAL) {
                     dactyl.focusContent(true);
-                    for (let frame in values(buffer.allFrames())) {
+                    for (let frame of values(buffer.allFrames())) {
                         // clear any selection made
                         let selection = frame.getSelection();
                         if (selection && !selection.isCollapsed)
@@ -194,11 +194,13 @@ var Modes = Module("modes", {
 
     NONE: 0,
 
-    __iterator__: function __iterator__() array.iterValues(this.all),
+    "@@iterator": function __iterator__() array.iterValues(this.all),
 
     get all() this._modes.slice(),
 
-    get mainModes() (mode for ([k, mode] in Iterator(modes._modeMap)) if (!mode.extended && mode.name == k)),
+    get mainModes() (mode
+                     for ([k, mode] of iter(modes._modeMap))
+                     if (!mode.extended && mode.name == k)),
 
     get mainMode() this._modeMap[this._main],
 
@@ -236,7 +238,7 @@ var Modes = Module("modes", {
 
     dumpStack: function dumpStack() {
         util.dump("Mode stack:");
-        for (let [i, mode] in array.iterItems(this._modeStack))
+        for (let [i, mode] of array.iterItems(this._modeStack))
             util.dump("    " + i + ": " + mode);
     },
 
@@ -283,7 +285,7 @@ var Modes = Module("modes", {
 
     save: function save(id, obj, prop, test) {
         if (!(id in this.boundProperties))
-            for (let elem in array.iterValues(this._modeStack))
+            for (let elem of array.iterValues(this._modeStack))
                 elem.saved[id] = { obj: obj, prop: prop, value: obj[prop], test: test };
         this.boundProperties[id] = { obj: util.weakReference(obj), prop: prop, test: test };
     },
@@ -328,7 +330,7 @@ var Modes = Module("modes", {
                     dactyl.trapErrors("leave", this.topOfStack.params,
                                       { push: push }, push);
 
-                for (let [id, { obj, prop, test }] in Iterator(this.boundProperties)) {
+                for (let [id, { obj, prop, test }] of iter(this.boundProperties)) {
                     obj = obj.get();
                     if (!obj)
                         delete this.boundProperties[id];
@@ -346,7 +348,7 @@ var Modes = Module("modes", {
         });
 
         if (stack && stack.pop)
-            for (let { obj, prop, value, test } in values(this.topOfStack.saved))
+            for (let { obj, prop, value, test } of values(this.topOfStack.saved))
                 if (!test || !test(stack, prev))
                     dactyl.trapErrors(function () { obj[prop] = value });
 
@@ -442,10 +444,10 @@ var Modes = Module("modes", {
             this.allBases.indexOf(obj) >= 0 || callable(obj) && this instanceof obj,
 
         allBases: Class.Memoize(function () {
-            let seen = RealSet(),
+            let seen = new RealSet,
                 res = [],
                 queue = [this].concat(this.bases);
-            for (let mode in array.iterValues(queue))
+            for (let mode of array.iterValues(queue))
                 if (!seen.add(mode)) {
                     res.push(mode);
                     queue.push.apply(queue, mode.bases);
@@ -537,15 +539,15 @@ var Modes = Module("modes", {
 
             let tree = {};
 
-            for (let mode in values(list))
+            for (let mode of values(list))
                 tree[mode.name] = {};
 
-            for (let mode in values(list))
-                for (let base in values(mode.bases))
+            for (let mode of values(list))
+                for (let base of values(mode.bases))
                     tree[base.name][mode.name] = tree[mode.name];
 
             let roots = iter([m.name, tree[m.name]]
-                             for (m in values(list))
+                             for (m of values(list))
                              if (!m.bases.length)).toObject();
 
             function rec(obj) {
@@ -632,7 +634,7 @@ var Modes = Module("modes", {
                                                     .every(k => hasOwnProperty(this.values, k)),
 
             get values() array.toObject([[m.name.toLowerCase(), m.description]
-                                         for (m in values(modes._modes)) if (!m.hidden)])
+                                         for (m of values(modes._modes)) if (!m.hidden)])
         };
 
         options.add(["passunknown", "pu"],
diff --git a/common/content/mow.js b/common/content/mow.js
index d3889916..fa30fc22 100644
--- a/common/content/mow.js
+++ b/common/content/mow.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -69,6 +69,7 @@ var MOW = Module("mow", {
     __noSuchMethod__: function (meth, args) Buffer[meth].apply(Buffer, [this.body].concat(args)),
 
     get widget() this.widgets.multilineOutput,
+
     widgets: Class.Memoize(function widgets() commandline.widgets),
 
     body: Class.Memoize(function body() this.widget.contentDocument.documentElement),
@@ -94,7 +95,7 @@ var MOW = Module("mow", {
 
                 leave: stack => {
                     if (stack.pop)
-                        for (let message in values(this.messages))
+                        for (let message of values(this.messages))
                             if (message.leave)
                                 message.leave(stack);
                 },
@@ -198,7 +199,7 @@ var MOW = Module("mow", {
                 selection: !window.document.commandDispatcher.focusedWindow.getSelection().isCollapsed
             };
 
-            for (let node in array.iterValues(menu.children)) {
+            for (let node of array.iterValues(menu.children)) {
                 let group = node.getAttributeNS(NS, "group");
                 node.hidden = group && !group.split(/\s+/).every(g => enabled[g]);
             }
@@ -228,7 +229,7 @@ var MOW = Module("mow", {
         if (!(open || this.visible))
             return;
 
-        let doc = this.widget.contentDocument;
+        let doc = this.document;
 
         let trim = this.spaceNeeded;
         let availableHeight = config.outputHeight - trim;
@@ -270,7 +271,7 @@ var MOW = Module("mow", {
         if (!this.visible || !isinstance(modes.main, modes.OUTPUT_MULTILINE))
             return this.widgets.message = null;
 
-        let elem = this.widget.contentDocument.documentElement;
+        let elem = this.document.documentElement;
 
         if (showHelp)
             this.widgets.message = ["MoreMsg", _("mow.moreHelp")];
diff --git a/common/content/quickmarks.js b/common/content/quickmarks.js
index 0fc4dc3d..9073b994 100644
--- a/common/content/quickmarks.js
+++ b/common/content/quickmarks.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2013 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -39,7 +39,7 @@ var QuickMarks = Module("quickmarks", {
      */
     find: function find(url) {
         let res = [];
-        for (let [k, v] in this._qmarks)
+        for (let [k, v] of this._qmarks)
             if (dactyl.parseURLs(v).some(u => String.replace(u, /#.*/, "") == url))
                 res.push(k);
         return res;
@@ -63,7 +63,7 @@ var QuickMarks = Module("quickmarks", {
     remove: function remove(filter) {
         let pattern = util.charListToRegexp(filter, "a-zA-Z0-9");
 
-        for (let [qmark, ] in this._qmarks) {
+        for (let [qmark, ] of this._qmarks) {
             if (pattern.test(qmark))
                 this._qmarks.remove(qmark);
         }
@@ -98,7 +98,7 @@ var QuickMarks = Module("quickmarks", {
      * @param {string} filter The list of quickmarks to display, e.g. "a-c i O-X".
      */
     list: function list(filter) {
-        let marks = [k for ([k, v] in this._qmarks)];
+        let marks = [k for ([k, v] of this._qmarks)];
         let lowercaseMarks = marks.filter(bind("test", /[a-z]/)).sort();
         let uppercaseMarks = marks.filter(bind("test", /[A-Z]/)).sort();
         let numberMarks    = marks.filter(bind("test", /[0-9]/)).sort();
@@ -110,11 +110,11 @@ var QuickMarks = Module("quickmarks", {
         if (filter.length > 0) {
             let pattern = util.charListToRegexp(filter, "a-zA-Z0-9");
             marks = marks.filter(qmark => pattern.test(qmark));
-            dactyl.assert(marks.length >= 0, _("quickmark.noMatching", filter.quote()));
+            dactyl.assert(marks.length >= 0, _("quickmark.noMatching", JSON.stringify(filter)));
         }
 
         commandline.commandOutput(template.tabular(["QuickMark", "URL"], [],
-            ([mark, quickmarks._qmarks.get(mark)] for ([k, mark] in Iterator(marks)))));
+            ([mark, quickmarks._qmarks.get(mark)] for (mark of marks))));
     }
 }, {
 }, {
diff --git a/common/content/statusline.js b/common/content/statusline.js
index 20ecf1cd..c83a98db 100644
--- a/common/content/statusline.js
+++ b/common/content/statusline.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
diff --git a/common/content/tabs.js b/common/content/tabs.js
index 308ca377..4bc436cc 100644
--- a/common/content/tabs.js
+++ b/common/content/tabs.js
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -42,7 +42,7 @@ var Tabs = Module("tabs", {
             false, true);
 
         this.timeout(function () {
-            for (let { linkedBrowser: { contentDocument } } in values(this.allTabs))
+            for (let { linkedBrowser: { contentDocument } } of this.allTabs)
                 if (contentDocument.readyState === "complete")
                     dactyl.initDocument(contentDocument);
         }, 1000);
@@ -61,9 +61,9 @@ var Tabs = Module("tabs", {
     _alternates: Class.Memoize(() => [config.tabbrowser.mCurrentTab, null]),
 
     cleanup: function cleanup() {
-        for (let [i, tab] in Iterator(this.allTabs)) {
+        for (let tab of this.allTabs) {
             let node = function node(class_) document.getAnonymousElementByAttribute(tab, "class", class_);
-            for (let elem in values(["dactyl-tab-icon-number", "dactyl-tab-number"].map(node)))
+            for (let elem of values(["dactyl-tab-icon-number", "dactyl-tab-number"].map(node)))
                 if (elem)
                     elem.parentNode.parentNode.removeChild(elem.parentNode);
 
@@ -73,7 +73,7 @@ var Tabs = Module("tabs", {
     },
 
     updateTabCount: function updateTabCount() {
-        for (let [i, tab] in Iterator(this.visibleTabs)) {
+        for (let [i, tab] of iter(this.visibleTabs)) {
             let node = function node(class_) document.getAnonymousElementByAttribute(tab, "class", class_);
             if (!node("dactyl-tab-number")) {
                 let img = node("tab-icon-image");
@@ -101,7 +101,7 @@ var Tabs = Module("tabs", {
         statusline.updateTabCount(true);
     },
 
-    _onTabSelect: function _onTabSelect() {
+    _onTabSelect: function* _onTabSelect() {
         // TODO: is all of that necessary?
         //       I vote no. --Kris
         modes.reset();
@@ -214,7 +214,7 @@ var Tabs = Module("tabs", {
      */
     // FIXME: Only called once...necessary?
     getContentIndex: function getContentIndex(content) {
-        for (let [i, browser] in this.browsers) {
+        for (let browser of this.browsers) {
             if (browser.contentWindow == content || browser.contentDocument == content)
                 return i;
         }
@@ -353,7 +353,7 @@ var Tabs = Module("tabs", {
      * @param {boolean} all If true, match against all tabs. If
      *      false, match only tabs in the current tab group.
      */
-    match: function match(filter, count, regexp, all) {
+    match: function* match(filter, count, regexp, all) {
         if (!filter && count == null)
             yield tabs.getTab();
         else if (!filter)
@@ -369,7 +369,7 @@ var Tabs = Module("tabs", {
                 else
                     var matcher = Styles.matchFilter(filter);
 
-                for (let tab in values(tabs[all ? "allTabs" : "visibleTabs"])) {
+                for (let tab of values(tabs[all ? "allTabs" : "visibleTabs"])) {
                     let browser = tab.linkedBrowser;
                     let uri = browser.currentURI;
                     let title;
@@ -510,7 +510,7 @@ var Tabs = Module("tabs", {
      * Stops loading all tabs.
      */
     stopAll: function stopAll() {
-        for (let [, browser] in this.browsers)
+        for (let browser of this.browsers)
             browser.stop();
     },
 
@@ -620,7 +620,7 @@ var Tabs = Module("tabs", {
             commands.add(params.name, params.description,
                 function (args) {
                     let removed = 0;
-                    for (let tab in tabs.match(args[0], args.count, args.bang, !params.visible)) {
+                    for (let tab of tabs.match(args[0], args.count, args.bang, !params.visible)) {
                         config.removeTab(tab);
                         removed++;
                     }
@@ -643,7 +643,7 @@ var Tabs = Module("tabs", {
         commands.add(["pin[tab]"],
             "Pin tab as an application tab",
             function (args) {
-                for (let tab in tabs.match(args[0], args.count))
+                for (let tab of tabs.match(args[0], args.count))
                     config.browser[!args.bang || !tab.pinned ? "pinTab" : "unpinTab"](tab);
             },
             {
@@ -660,7 +660,7 @@ var Tabs = Module("tabs", {
         commands.add(["unpin[tab]"],
             "Unpin tab as an application tab",
             function (args) {
-                for (let tab in tabs.match(args[0], args.count))
+                for (let tab of tabs.match(args[0], args.count))
                     config.browser.unpinTab(tab);
             },
             {
@@ -719,7 +719,7 @@ var Tabs = Module("tabs", {
         commands.add(["tabd[o]", "bufd[o]"],
             "Execute a command in each tab",
             function (args) {
-                for (let tab in values(tabs.visibleTabs)) {
+                for (let tab of values(tabs.visibleTabs)) {
                     tabs.select(tab);
                     dactyl.execute(args[0], null, true);
                 }
@@ -841,7 +841,7 @@ var Tabs = Module("tabs", {
                     let arg = args[0];
 
                     if (tabs.indexFromSpec(arg) == -1) {
-                        let list = [tab for (tab in tabs.match(args[0], args.count, true))];
+                        let list = [tab for (tab of tabs.match(args[0], args.count, true))];
                         dactyl.assert(list.length, _("error.invalidArgument", arg));
                         dactyl.assert(list.length == 1, _("buffer.multipleMatching", arg));
                         arg = list[0];
@@ -886,7 +886,7 @@ var Tabs = Module("tabs", {
                     if (options.get("activate").has("tabopen"))
                         activate = !activate;
 
-                    for (let i in util.range(0, Math.max(1, args.count)))
+                    for (let i of util.range(0, Math.max(1, args.count)))
                         tabs.cloneTab(tab, activate);
                 }, {
                     argCount: "0",
@@ -982,7 +982,7 @@ var Tabs = Module("tabs", {
                     if (m)
                         window.undoCloseTab(Number(m[1]) - 1);
                     else if (args) {
-                        for (let [i, item] in Iterator(tabs.closedTabs))
+                        for (let [i, item] of iter(tabs.closedTabs))
                             if (item.state.entries[item.state.index - 1].url == args) {
                                 window.undoCloseTab(i);
                                 return;
@@ -1009,7 +1009,7 @@ var Tabs = Module("tabs", {
             commands.add(["undoa[ll]"],
                 "Undo closing of all closed tabs",
                 function (args) {
-                    for (let i in Iterator(tabs.closedTabs))
+                    for (let i of iter(tabs.closedTabs))
                         window.undoCloseTab(0);
 
                 },
@@ -1064,7 +1064,7 @@ var Tabs = Module("tabs", {
             context.compare = CompletionContext.Sort.number;
             context.filters[0] = CompletionContext.Filter.textDescription;
 
-            for (let [id, vals] in Iterator(tabGroups))
+            for (let [id, vals] of iter(tabGroups))
                 context.fork(id, 0, this, function (context, [name, browsers]) {
                     context.title = [name || "Buffers"];
                     context.generate = () =>
@@ -1111,7 +1111,7 @@ var Tabs = Module("tabs", {
         function callback() {
             tabs.timeout(function () { this.updateTabCount(); });
         }
-        for (let event in values(["TabMove", "TabOpen", "TabClose"]))
+        for (let event of ["TabMove", "TabOpen", "TabClose"])
             events.listen(tabContainer, event, callback, false);
         events.listen(tabContainer, "TabSelect", tabs.bound._onTabSelect, false);
     },
@@ -1257,13 +1257,13 @@ var Tabs = Module("tabs", {
             ];
             options.add(["activate", "act"],
                 "Define when newly created tabs are automatically activated",
-                "stringlist", [g[0] for (g in values(activateGroups.slice(1))) if (!g[2] || !prefs.get("browser.tabs." + g[2]))].join(","),
+                "stringlist", [g[0] for (g of values(activateGroups.slice(1))) if (!g[2] || !prefs.get("browser.tabs." + g[2]))].join(","),
                 {
                     values: activateGroups,
                     has: Option.has.toggleAll,
                     setter: function (newValues) {
-                        let valueSet = RealSet(newValues);
-                        for (let group in values(activateGroups))
+                        let valueSet = new RealSet(newValues);
+                        for (let group of values(activateGroups))
                             if (group[2])
                                 prefs.safeSet("browser.tabs." + group[2],
                                               !(valueSet.has("all") ^ valueSet.has(group[0])),
@@ -1292,7 +1292,7 @@ var Tabs = Module("tabs", {
                 {
                     setter: function (values) {
                         let open = 1, restriction = 0;
-                        for (let [, opt] in Iterator(values)) {
+                        for (let opt of values) {
                             if (opt == "tab")
                                 open = 3;
                             else if (opt == "window")
diff --git a/common/modules/addons.jsm b/common/modules/addons.jsm
index b42db8d7..60973dd7 100644
--- a/common/modules/addons.jsm
+++ b/common/modules/addons.jsm
@@ -54,7 +54,7 @@ var updateAddons = Class("UpgradeListener", AddonListener, {
         this.remaining = addons;
         this.upgrade = [];
         this.dactyl.echomsg(_("addon.check", addons.map(a => a.name).join(", ")));
-        for (let addon in values(addons))
+        for (let addon of values(addons))
             addon.findUpdates(this, AddonManager.UPDATE_WHEN_USER_REQUESTED, null, null);
 
     },
@@ -226,7 +226,7 @@ var Addon = Class("Addon", {
         this.nodes.description.textContent = this.description;
         DOM(this.nodes.row).attr("active", this.isActive || null);
 
-        for (let node in values(this.nodes))
+        for (let node of values(this.nodes))
             if (node.update && node.update !== callee)
                 node.update();
 
@@ -394,7 +394,7 @@ var Addons = Module("addons", {
                 else if (file.isReadable() && file.isFile())
                     AddonManager.getInstallForFile(file.file, install, "application/x-xpinstall");
                 else if (file.isDirectory())
-                    dactyl.echoerr(_("addon.cantInstallDir", file.path.quote()));
+                    dactyl.echoerr(_("addon.cantInstallDir", JSON.stringify(file.path)));
                 else
                     dactyl.echoerr(_("io.notReadable", file.path));
             }, {
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index 024be9d9..7e5de80c 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2009-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2009-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -36,7 +36,7 @@ if (!("find" in Array.prototype))
         configurable: true,
         writable: true,
         value: function Array_find(pred, self) {
-            for (let [i, elem] in Iterator(this))
+            for (let [i, elem] of this.entries())
                 if (pred.call(self, elem, i, this))
                     return elem;
         }
@@ -47,7 +47,7 @@ if (!("findIndex" in Array.prototype))
         configurable: true,
         writable: true,
         value: function Array_findIndex(pred, self) {
-            for (let [i, elem] in Iterator(this))
+            for (let [i, elem] of this.entries())
                 if (pred.call(self, elem, i, this))
                     return i;
             return -1;
@@ -86,7 +86,7 @@ function defineModule(name, params, module) {
     defineModule.loadLog.push("[Begin " + name + "]");
     defineModule.prefix += "  ";
 
-    for (let [, mod] in Iterator(params.require || []))
+    for (let mod of (params.require || []))
         require(mod, module);
 
     module._lastModule = currentModule;
@@ -105,13 +105,20 @@ Object.defineProperty(defineModule.loadLog, "push", {
 });
 defineModule.prefix = "";
 defineModule.dump = function dump_(...args) {
-    let msg = args.map(function (msg) {
-        if (loaded.util && typeof msg == "object")
-            msg = util.objectToString(msg);
-        return msg;
-    }).join(", ");
-    dump(String.replace(msg, /\n?$/, "\n")
-               .replace(/^./gm, JSMLoader.name + ": $&"));
+    try {
+        let msg = args.map(function (msg) {
+            if (loaded.util && typeof msg == "object")
+                msg = util.objectToString(msg);
+            return msg;
+        }).join(", ");
+        dump(String.replace(msg, /\n?$/, "\n")
+                   .replace(/^./gm, JSMLoader.name + ": $&"));
+    }
+    catch (e) {
+        let msg = "Error dumping object: " + e + "\n" + (e && e.stack || Error.stack);
+        dump(String.replace(msg, /\n?$/, "\n")
+                   .replace(/^./gm, JSMLoader.name + ": $&"));
+    }
 }
 defineModule.modules = [];
 defineModule.time = function time(major, minor, func, self, ...args) {
@@ -175,6 +182,7 @@ defineModule("base", {
         "Cr",
         "Cs",
         "Cu",
+        "DOMPromise",
         "ErrorBase",
         "Finished",
         "JSMLoader",
@@ -184,6 +192,7 @@ defineModule("base", {
         "Set",
         "Struct",
         "StructBase",
+        "Symbol",
         "TextEncoder",
         "TextDecoder",
         "Timer",
@@ -191,6 +200,7 @@ defineModule("base", {
         "XPCOM",
         "XPCOMShim",
         "XPCOMUtils",
+        "apply",
         "array",
         "bind",
         "call",
@@ -200,7 +210,6 @@ defineModule("base", {
         "defineModule",
         "deprecated",
         "endModule",
-        "forEach",
         "hasOwnProperty",
         "isArray",
         "isGenerator",
@@ -209,12 +218,11 @@ defineModule("base", {
         "isSubclass",
         "isinstance",
         "iter",
-        "iterAll",
         "iterOwnProperties",
         "keys",
         "literal",
         "memoize",
-        "modujle",
+        "module",
         "octal",
         "properties",
         "require",
@@ -232,6 +240,11 @@ this.lazyRequire("services", ["services"]);
 this.lazyRequire("storage", ["File"]);
 this.lazyRequire("util", ["FailedAssertion", "util"]);
 
+if (typeof Symbol == "undefined")
+    this.Symbol = {
+        iterator: "@@iterator",
+    };
+
 literal.files = {};
 literal.locations = {};
 function literal(comment) {
@@ -254,6 +267,12 @@ function literal(comment) {
     });
 }
 
+function apply(obj, meth, args) {
+    // The function's own apply method breaks in strange ways
+    // when using CPOWs.
+    Function.prototype.apply.call(obj[meth], obj, args);
+}
+
 /**
  * Iterates over the names of all of the top-level properties of an
  * object or, if prototypes is given, all of the properties in the
@@ -269,13 +288,13 @@ function prototype(obj)
     XPCNativeWrapper.unwrap(obj).__proto__ ||
     Object.getPrototypeOf(XPCNativeWrapper.unwrap(obj));
 
-function properties(obj, prototypes) {
+function* properties(obj, prototypes) {
     let orig = obj;
-    let seen = RealSet(["dactylPropertyNames"]);
+    let seen = new RealSet(["dactylPropertyNames"]);
 
     try {
         if ("dactylPropertyNames" in obj && !prototypes)
-            for (let key in values(obj.dactylPropertyNames))
+            for (let key of obj.dactylPropertyNames)
                 if (key in obj && !seen.add(key))
                     yield key;
     }
@@ -321,8 +340,8 @@ function properties(obj, prototypes) {
     }
 }
 
-function iterOwnProperties(obj) {
-    for (let prop in properties(obj))
+function* iterOwnProperties(obj) {
+    for (let prop of properties(obj))
         yield [prop, Object.getOwnPropertyDescriptor(obj, prop)];
 }
 
@@ -358,7 +377,7 @@ function deprecated(alternative, fn) {
 }
 deprecated.warn = function warn(func, name, alternative, frame) {
     if (!func.seenCaller)
-        func.seenCaller = RealSet([
+        func.seenCaller = new RealSet([
             "resource://dactyl/javascript.jsm",
             "resource://dactyl/util.jsm"
         ]);
@@ -383,15 +402,13 @@ deprecated.warn = function warn(func, name, alternative, frame) {
  * @param {object} obj The object to inspect.
  * @returns {Generator}
  */
-function keys(obj) iter(function keys() {
+function keys(obj) {
     if (isinstance(obj, ["Map"]))
-        for (let [k, v] of obj)
-            yield k;
-    else
-        for (var k in obj)
-            if (hasOwnProperty(obj, k))
-                yield k;
-}());
+        return iter(obj.keys());
+
+    return iter(k for (k in obj)
+                if (hasOwnProperty(obj, k)));
+}
 
 /**
  * Iterates over all of the top-level, iterable property values of an
@@ -400,24 +417,19 @@ function keys(obj) iter(function keys() {
  * @param {object} obj The object to inspect.
  * @returns {Generator}
  */
-function values(obj) iter(function values() {
+function values(obj)  {
     if (isinstance(obj, ["Map"]))
-        for (let [k, v] of obj)
-            yield v;
-    else if (isinstance(obj, ["Generator", "Iterator", Iter]))
-        for (let k in obj)
-            yield k;
-    else if (iter.iteratorProp in obj)
-        for (let v of obj)
-            yield v;
-    else
-        for (var k in obj)
-            if (hasOwnProperty(obj, k))
-                yield obj[k];
-}());
-
-var forEach = deprecated("iter.forEach", function forEach() iter.forEach.apply(iter, arguments));
-var iterAll = deprecated("iter", function iterAll() iter.apply(null, arguments));
+        return iter(obj.values());
+
+    if (isinstance(obj, ["Generator", "Iterator", Iter]))
+        return iter(k for (k of obj));
+
+    if (Symbol.iterator in obj)
+        return iter(obj[Symbol.iterator]());
+
+    return iter(obj[k] for (k in obj)
+                if (hasOwnProperty(obj, k)));
+}
 
 var RealSet = Set;
 let Set_add = RealSet.prototype.add;
@@ -436,7 +448,7 @@ Object.defineProperty(RealSet.prototype, "difference", {
     configurable: true,
     writable: true,
     value: function RealSet_difference(set) {
-        return RealSet(i for (i of this) if (!set.has(i)));
+        return new RealSet(i for (i of this) if (!set.has(i)));
     },
 });
 
@@ -444,7 +456,7 @@ Object.defineProperty(RealSet.prototype, "intersection", {
     configurable: true,
     writable: true,
     value: function RealSet_intersection(set) {
-        return RealSet(i for (i of this) if (set.has(i)));
+        return new RealSet(i for (i of this) if (set.has(i)));
     },
 });
 
@@ -452,7 +464,7 @@ Object.defineProperty(RealSet.prototype, "union", {
     configurable: true,
     writable: true,
     value: function RealSet_union(set) {
-        let res = RealSet(this);
+        let res = new RealSet(this);
         for (let item of set)
             res.add(item);
         return res;
@@ -469,7 +481,7 @@ Object.defineProperty(RealSet.prototype, "union", {
 this.Set = deprecated("RealSet", function Set(ary) {
     let obj = {};
     if (ary)
-        for (let val in values(ary))
+        for (let val of values(ary))
             obj[val] = true;
     return obj;
 });
@@ -519,7 +531,7 @@ Set.subtract = deprecated("RealSet#difference",
     function set_subtract(set) {
         set = update({}, set);
         for (let i = 1; i < arguments.length; i++)
-            for (let k in keys(arguments[i]))
+            for (let k of keys(arguments[i]))
                 delete set[k];
         return set;
     });
@@ -602,9 +614,11 @@ function curry(fn, length, self, acc) {
     return curried;
 }
 
-var bind = function bind(meth, self, ...args)
-    let (func = callable(meth) ? meth : self[meth])
-        func.bind.apply(func, [self].concat(args));
+var bind = function bind(meth, self, ...args) {
+    let func = callable(meth) ? meth : self[meth];
+
+    return func.bind.apply(func, [self].concat(args));
+}
 
 /**
  * Returns true if both arguments are functions and
@@ -748,12 +762,11 @@ function memoize(obj, key, getter) {
     }
 }
 
-
 let sandbox = Cu.Sandbox(Cc["@mozilla.org/systemprincipal;1"].createInstance(),
-                         { wantGlobalProperties: ["TextDecoder", "TextEncoder"] });
-sandbox.__proto__ = this;
+                         { wantGlobalProperties: ["TextDecoder", "TextEncoder"],
+                           sandboxPrototype: this });
 
-var { TextEncoder, TextDecoder } = sandbox;
+var { TextEncoder, TextDecoder, Promise: DOMPromise } = sandbox;
 
 /**
  * Updates an object with the properties of another object. Getters
@@ -787,13 +800,21 @@ function update(target) {
                     let func = desc.value.wrapped || desc.value;
                     if (!func.superapply) {
                         func.__defineGetter__("super", function get_super() Object.getPrototypeOf(target)[k]);
-                        func.superapply = function superapply(self, args)
-                            let (meth = Object.getPrototypeOf(target)[k])
-                                meth && meth.apply(self, args);
-                        func.supercall = function supercall(self, ...args)
-                            func.superapply(self, args);
+
+                        func.superapply = function superapply(self, args) {
+                            let meth = Object.getPrototypeOf(target)[k];
+                            return meth && meth.apply(self, args);
+                        }
+
+                        func.supercall = function supercall(self, ...args) {
+                            return func.superapply(self, args);
+                        }
                     }
                 }
+
+                if (k.startsWith("@@") && k.slice(2) in Symbol)
+                    k = Symbol[k.slice(2)];
+
                 Object.defineProperty(target, k, desc);
             }
             catch (e) {}
@@ -952,9 +973,9 @@ Class.Memoize = function Memoize(getter, wait)
                         }
                     });
 
-                    Task.spawn(function () {
+                    Task.spawn(function* () {
                         let wait;
-                        for (var res in getter.call(obj)) {
+                        for (var res of getter.call(obj)) {
                             if (wait !== undefined)
                                 yield promises.sleep(wait);
                             wait = res;
@@ -981,8 +1002,6 @@ Class.Memoize = function Memoize(getter, wait)
         }
     });
 
-Class.memoize = deprecated("Class.Memoize", function memoize() Class.Memoize.apply(this, arguments));
-
 /**
  * Updates the given object with the object in the target class's
  * prototype.
@@ -1025,7 +1044,7 @@ Class.prototype = {
     toString: function C_toString() {
         if (this.toStringParams)
             var params = "(" + this.toStringParams.map(m => (isArray(m)  ? "[" + m + "]" :
-                                                             isString(m) ? m.quote() : String(m)))
+                                                             isString(m) ? JSON.stringify(m) : String(m)))
                                    .join(", ") + ")";
         return "[instance " + this.constructor.className + (params || "") + "]";
     },
@@ -1077,6 +1096,9 @@ Class.prototype = {
         for (let i = 0; i < arguments.length; i++) {
             let src = arguments[i];
             Object.getOwnPropertyNames(src || {}).forEach((k) => {
+                if (k.startsWith("@@") && k.slice(2) in Symbol)
+                    k = Symbol[k.slice(2)];
+
                 let desc = Object.getOwnPropertyDescriptor(src, k);
                 if (desc.value instanceof Class.Property)
                     desc = desc.value.init(k, this) || desc.value;
@@ -1098,6 +1120,9 @@ Class.prototype = {
                 }
 
                 try {
+                    if (k.startsWith("@@") && k.slice(2) in Symbol)
+                        k = Symbol[k.slice(2)];
+
                     if ("value" in desc && (this.localizedProperties.has(k) || this.magicalProperties.has(k)))
                         this[k] = desc.value;
                     else
@@ -1109,10 +1134,19 @@ Class.prototype = {
         return this;
     },
 
-    localizedProperties: RealSet(),
-    magicalProperties: RealSet()
+    localizedProperties: new RealSet,
+    magicalProperties: new RealSet
 };
-for (let name in properties(Class.prototype)) {
+
+/*
+Object.defineProperty(Class.prototype, Symbol.iterator, {
+    get: function () this.__iterator__,
+    set: function (val) { this.__iterator__ = val },
+    configurable: true
+});
+*/
+
+for (let name of properties(Class.prototype)) {
     let desc = Object.getOwnPropertyDescriptor(Class.prototype, name);
     desc.enumerable = false;
     Object.defineProperty(Class.prototype, name, desc);
@@ -1165,14 +1199,22 @@ function XPCOM(interfaces, superClass) {
 
     let shim = XPCOMShim(interfaces);
 
-    let res = Class("XPCOM(" + interfaces + ")", superClass || Class,
-        update(iter([k,
-                     v === undefined || callable(v) ? stub : v]
-                     for ([k, v] in Iterator(shim))).toObject(),
-               { QueryInterface: XPCOMUtils.generateQI(interfaces) }));
+    let base = { QueryInterface: XPCOMUtils.generateQI(interfaces) };
+
+    for (let [k, v] of iter(shim)) {
+        if (v === undefined || callable(v))
+            base[k] = stub;
+        else
+            base[k] = v;
+    }
+
+    let res = Class("XPCOM(" + interfaces + ")",
+                    superClass || Class,
+                    base);
 
     return res;
 }
+
 function XPCOMShim(interfaces) {
     let ip = services.InterfacePointer({
         QueryInterface: function (iid) {
@@ -1336,9 +1378,9 @@ var StructBase = Class("StructBase", Array, {
     toString: function struct_toString() Class.prototype.toString.apply(this, arguments),
 
     // Iterator over our named members
-    __iterator__: function struct__iterator__() {
-        let self = this;
-        return ([k, self[k]] for (k in keys(self.members)))
+    "@@iterator": function* struct__iterator__() {
+        for (let k of keys(this.members))
+            yield [k, this[k]];
     }
 }, {
     fromArray: function fromArray(ary) {
@@ -1486,59 +1528,60 @@ var octal = deprecated("octal integer literals", function octal(decimal) parseIn
  * @param {nsIJSIID} iface The interface to which to query all elements.
  * @returns {Generator}
  */
-iter.iteratorProp = "@@iterator" in [] ? "@@iterator" : "iterator";
 function iter(obj, iface) {
     if (arguments.length == 2 && iface instanceof Ci.nsIJSIID)
         return iter(obj).map(item => item.QueryInterface(iface));
 
     let args = arguments;
-    let res = Iterator(obj);
+    let res;
 
     if (args.length > 1)
-        res = (function () {
+        res = (function* () {
             for (let i = 0; i < args.length; i++)
-                for (let j in iter(args[i]))
+                for (let j of iter(args[i]))
                     yield j;
         })();
-    else if (isinstance(obj, ["Iterator", "Generator", "Array"]))
-        ;
+    else if (isinstance(obj, ["Array"]))
+        res = obj.entries();
+    else if (Symbol.iterator in obj)
+        res = obj[Symbol.iterator]();
     else if (isinstance(obj, [Ci.nsIDOMHTMLCollection, Ci.nsIDOMNodeList]))
         res = array.iterItems(obj);
-    else if (iter.iteratorProp in obj && callable(obj[iter.iteratorProp]) && !("__iterator__" in obj))
-        res = (x for (x of obj));
     else if (ctypes && ctypes.CData && obj instanceof ctypes.CData) {
         while (obj.constructor instanceof ctypes.PointerType)
             obj = obj.contents;
         if (obj.constructor instanceof ctypes.ArrayType)
             res = array.iterItems(obj);
         else if (obj.constructor instanceof ctypes.StructType)
-            res = (function () {
-                for (let prop in values(obj.constructor.fields))
-                    yield let ([name, type] = Iterator(prop).next()) [name, obj[name]];
+            res = (function* () {
+                for (let prop of values(obj.constructor.fields)) {
+                    let [name, type] = Iterator(prop).next();
+                    yield [name, obj[name]];
+                }
             })();
         else
             return iter({});
     }
     else if (Ci.nsIDOMNamedNodeMap && obj instanceof Ci.nsIDOMNamedNodeMap ||
              Ci.nsIDOMMozNamedAttrMap && obj instanceof Ci.nsIDOMMozNamedAttrMap)
-        res = (function () {
+        res = (function* () {
             for (let i = 0; i < obj.length; i++)
                 yield [obj.name, obj];
         })();
     else if (obj instanceof Ci.mozIStorageStatement)
-        res = (function (obj) {
+        res = (function* (obj) {
             while (obj.executeStep())
                 yield obj.row;
             obj.reset();
         })(obj);
     else if ("getNext" in obj) {
         if ("hasMoreElements" in obj)
-            res = (function () {
+            res = (function* () {
                 while (obj.hasMoreElements())
                     yield obj.getNext();
             })();
         else if ("hasMore" in obj)
-            res = (function () {
+            res = (function* () {
                 while (obj.hasMore())
                     yield obj.getNext();
             })();
@@ -1548,6 +1591,10 @@ function iter(obj, iface) {
             return iter(obj.enumerator());
         return iter(obj.enumerator);
     }
+
+    if (res === undefined)
+        res = Iterator(obj)[Symbol.iterator]();
+
     return Iter(res);
 }
 update(iter, {
@@ -1556,7 +1603,7 @@ update(iter, {
     // See array.prototype for API docs.
     toObject: function toObject(iter) {
         let obj = {};
-        for (let [k, v] in iter)
+        for (let [k, v] of iter)
             if (v instanceof Class.Property)
                 Object.defineProperty(obj, k, v.init(k, obj) || v);
             else
@@ -1564,7 +1611,7 @@ update(iter, {
         return obj;
     },
 
-    compact: function compact(iter) (item for (item in iter) if (item != null)),
+    compact: function compact(iter) (item for (item of iter) if (item != null)),
 
     every: function every(iter, pred, self) {
         pred = pred || util.identity;
@@ -1581,7 +1628,7 @@ update(iter, {
         return false;
     },
 
-    filter: function filter(iter, pred, self) {
+    filter: function* filter(iter, pred, self) {
         for (let elem of iter)
             if (pred.call(self, elem))
                 yield elem;
@@ -1618,7 +1665,7 @@ update(iter, {
      * @param {function} func
      * @returns {Array}
      */
-    map: function map(iter, func, self) {
+    map: function* map(iter, func, self) {
         for (let i of iter)
             yield func.call(self, i);
     },
@@ -1651,8 +1698,8 @@ update(iter, {
     sort: function sort(iter, fn, self)
         array(this.toArray(iter).sort(fn, self)),
 
-    uniq: function uniq(iter) {
-        let seen = RealSet();
+    uniq: function* uniq(iter) {
+        let seen = new RealSet;
         for (let item of iter)
             if (!seen.add(item))
                 yield item;
@@ -1666,7 +1713,7 @@ update(iter, {
      * @param {Array} ary2
      * @returns {Array}
      */
-    zip: function zip(iter1, iter2) {
+    zip: function* zip(iter1, iter2) {
         try {
             yield [iter1.next(), iter2.next()];
         }
@@ -1688,7 +1735,7 @@ const Iter = Class("Iter", {
 
     send: function send() this.iter.send.apply(this.iter, arguments),
 
-    __iterator__: function () this.iter
+    "@@iterator": function () this.iter,
 });
 iter.Iter = Iter;
 
@@ -1710,8 +1757,10 @@ function arrayWrap(fn) {
  */
 var array = Class("array", Array, {
     init: function (ary) {
-        if (isinstance(ary, ["Iterator", "Generator"]) || "__iterator__" in ary)
-            ary = [k for (k in ary)];
+        if (Symbol.iterator in ary)
+            ary = [k for (k of ary)];
+        else if (isinstance(ary, ["Iterator", "Generator"]) || Symbol.iterator in ary)
+            ary = [k for (k of ary)];
         else if (ary.length)
             ary = Array.slice(ary);
 
@@ -1793,7 +1842,7 @@ var array = Class("array", Array, {
      * @param {Array} ary
      * @returns {Iterator(Object)}
      */
-    iterValues: function iterValues(ary) {
+    iterValues: function* iterValues(ary) {
         for (let i = 0; i < ary.length; i++)
             yield ary[i];
     },
@@ -1804,7 +1853,7 @@ var array = Class("array", Array, {
      * @param {Array} ary
      * @returns {Iterator([{number}, {Object}])}
      */
-    iterItems: function iterItems(ary) {
+    iterItems: function* iterItems(ary) {
         let length = ary.length;
         for (let i = 0; i < length; i++)
             yield [i, ary[i]];
@@ -1815,7 +1864,7 @@ var array = Class("array", Array, {
      * given predicate.
      */
     nth: function nth(ary, pred, n, self) {
-        for (let elem in values(ary))
+        for (let elem of values(ary))
             if (pred.call(self, elem) && n-- === 0)
                 return elem;
         return undefined;
@@ -1832,12 +1881,12 @@ var array = Class("array", Array, {
     uniq: function uniq(ary, unsorted) {
         let res = [];
         if (unsorted) {
-            for (let item in values(ary))
+            for (let item of ary)
                 if (res.indexOf(item) == -1)
                     res.push(item);
         }
         else {
-            for (let [, item] in Iterator(ary.sort())) {
+            for (let item of ary.sort()) {
                 if (item != last || !res.length)
                     res.push(item);
                 var last = item;
@@ -1856,7 +1905,7 @@ var array = Class("array", Array, {
      */
     zip: function zip(ary1, ary2) {
         let res = [];
-        for (let [i, item] in Iterator(ary1))
+        for (let [i, item] of iter(ary1))
             res.push([item, i in ary2 ? ary2[i] : ""]);
         return res;
     }
diff --git a/common/modules/bookmarkcache.jsm b/common/modules/bookmarkcache.jsm
index 66d056c8..b5f6613c 100644
--- a/common/modules/bookmarkcache.jsm
+++ b/common/modules/bookmarkcache.jsm
@@ -1,4 +1,4 @@
-// Copyright ©2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright ©2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -83,11 +83,13 @@ var BookmarkCache = Module("BookmarkCache", XPCOM(Ci.nsINavBookmarkObserver), {
         services.bookmarks.removeObserver(this);
     },
 
-    __iterator__: function () (val for ([, val] in Iterator(bookmarkcache.bookmarks))),
+    "@@iterator": function () values(bookmarkcache.bookmarks),
 
     bookmarks: Class.Memoize(function () this.load()),
 
-    keywords: Class.Memoize(function () array.toObject([[b.keyword, b] for (b in this) if (b.keyword)])),
+    keywords: Class.Memoize(function () array.toObject([[b.keyword, b]
+                                                        for (b of this)
+                                                        if (b.keyword)])),
 
     rootFolders: ["toolbarFolder", "bookmarksMenuFolder", "unfiledBookmarksFolder"]
         .map(s => services.bookmarks[s]),
@@ -123,7 +125,7 @@ var BookmarkCache = Module("BookmarkCache", XPCOM(Ci.nsINavBookmarkObserver), {
 
     get: function (url) {
         let ids = services.bookmarks.getBookmarkIdsForURI(newURI(url), {});
-        for (let id in values(ids))
+        for (let id of values(ids))
             if (id in this.bookmarks)
                 return this.bookmarks[id];
         return null;
diff --git a/common/modules/buffer.jsm b/common/modules/buffer.jsm
index 839a7f7d..79c44281 100644
--- a/common/modules/buffer.jsm
+++ b/common/modules/buffer.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -77,8 +77,9 @@ var Buffer = Module("Buffer", {
     /**
      * Content preference methods.
      */
-    prefs: Class.Memoize(function ()
-        let (self = this) ({
+    prefs: Class.Memoize(function () {
+        let self = this;
+        return {
             /**
              * Returns a promise for the given preference name.
              *
@@ -132,7 +133,8 @@ var Buffer = Module("Buffer", {
                       handleResult: resolve,
                       handleError: reject });
             })
-        })),
+        };
+    }),
 
     /**
      * Gets a content preference for the given buffer.
@@ -495,15 +497,15 @@ var Buffer = Module("Buffer", {
         let relRev = ["next", "prev"];
         let rev = relRev[1 - relRev.indexOf(rel)];
 
-        function followFrame(frame) {
-            function iter(elems) {
+        function* followFrame(frame) {
+            function* iter(elems) {
                 for (let i = 0; i < elems.length; i++)
                     if (elems[i].rel.toLowerCase() === rel || elems[i].rev.toLowerCase() === rev)
                         yield elems[i];
             }
 
             let elems = frame.document.getElementsByTagName("link");
-            for (let elem in iter(elems))
+            for (let elem of iter(elems))
                 yield elem;
 
             function a(regexp, elem) regexp.test(elem.textContent) === regexp.result ||
@@ -516,14 +518,14 @@ var Buffer = Module("Buffer", {
                                    Hints.isVisible);
 
             for (let test of [a, b])
-                for (let regexp in values(regexps))
-                    for (let i in util.range(res.length, 0, -1))
+                for (let regexp of values(regexps))
+                    for (let i of util.range(res.length, 0, -1))
                         if (test(regexp, res[i]))
                             yield res[i];
         }
 
-        for (let frame in values(this.allFrames(null, true)))
-            for (let elem in followFrame(frame))
+        for (let frame of values(this.allFrames(null, true)))
+            for (let elem of followFrame(frame))
                 if (count-- === 0) {
                     if (follow)
                         this.followLink(elem, dactyl.CURRENT_TAB);
@@ -936,7 +938,7 @@ var Buffer = Module("Buffer", {
 
         if (!elem) {
             let area = -1;
-            for (let e in DOM(Buffer.SCROLLABLE_SEARCH_SELECTOR,
+            for (let e of DOM(Buffer.SCROLLABLE_SEARCH_SELECTOR,
                               this.focusedFrame.document)) {
                 if (Buffer.isScrollable(e, dir, horizontal)) {
                     let r = DOM(e).rect;
@@ -980,7 +982,7 @@ var Buffer = Module("Buffer", {
         if (win.scrollMaxX > 0 || win.scrollMaxY > 0)
             return win;
 
-        for (let frame in array.iterValues(win.frames))
+        for (let frame of array.iterValues(win.frames))
             if (frame.scrollMaxX > 0 || frame.scrollMaxY > 0)
                 return frame;
 
@@ -1011,7 +1013,7 @@ var Buffer = Module("Buffer", {
                                : rect => rect.top;
 
         let elems = [[e, distance(e.getBoundingClientRect())]
-                     for (e in path.matcher(this.focusedFrame.document))]
+                     for (e of path.matcher(this.focusedFrame.document))]
                         .filter(e => e[1] > FUDGE)
                         .sort((a, b) => a[1] - b[1]);
 
@@ -1048,9 +1050,12 @@ var Buffer = Module("Buffer", {
 
         // remove all hidden frames
         frames = frames.filter(frame => !(frame.document.body instanceof Ci.nsIDOMHTMLFrameSetElement))
-                       .filter(frame => !frame.frameElement ||
-            let (rect = frame.frameElement.getBoundingClientRect())
-                rect.width && rect.height);
+                       .filter(frame => {
+            if (!frame.frameElement)
+                return false;
+            let rect = frame.frameElement.getBoundingClientRect();
+            return rect.width && rect.height;
+        });
 
         // find the currently focused frame index
         let current = Math.max(0, frames.indexOf(this.focusedFrame));
@@ -1115,7 +1120,7 @@ var Buffer = Module("Buffer", {
             if (bookmarkcache.isBookmarked(this.URL))
                 info += ", " + _("buffer.bookmarked");
 
-            let pageInfoText = [file.quote(), " [", info, "] ", title].join("");
+            let pageInfoText = [JSON.stringify(file), " [", info, "] ", title].join("");
             dactyl.echo(pageInfoText, commandline.FORCE_SINGLELINE);
             return;
         }
@@ -1357,7 +1362,7 @@ var Buffer = Module("Buffer", {
     /**
      * Updates the zoom level of this buffer from a content preference.
      */
-    updateZoom: promises.task(function updateZoom() {
+    updateZoom: promises.task(function* updateZoom() {
         let uri = this.uri;
 
         if (prefs.get("browser.zoom.siteSpecific")) {
@@ -1482,10 +1487,10 @@ var Buffer = Module("Buffer", {
     get ZOOM_MIN() prefs.get("zoom.minPercent"),
     get ZOOM_MAX() prefs.get("zoom.maxPercent"),
 
-    setZoom: deprecated("buffer.setZoom", function setZoom()
-                        let ({ buffer } = overlay.activeModules) buffer.setZoom.apply(buffer, arguments)),
-    bumpZoomLevel: deprecated("buffer.bumpZoomLevel", function bumpZoomLevel()
-                              let ({ buffer } = overlay.activeModules) buffer.bumpZoomLevel.apply(buffer, arguments)),
+    setZoom: deprecated("buffer.setZoom",
+                        function setZoom(...args) apply(overlay.activeModules.buffer, "setZoom", args)),
+    bumpZoomLevel: deprecated("buffer.bumpZoomLevel",
+                              function bumpZoomLevel(...args) apply(overlay.activeModules.buffer, "bumpZoomLevel", args)),
 
     /**
      * Returns the currently selected word in *win*. If the selection is
@@ -1554,10 +1559,10 @@ var Buffer = Module("Buffer", {
                                                  .replace(re, ext), title]);
     },
 
-    findScrollableWindow: deprecated("buffer.findScrollableWindow", function findScrollableWindow()
-                                     let ({ buffer } = overlay.activeModules) buffer.findScrollableWindow.apply(buffer, arguments)),
-    findScrollable: deprecated("buffer.findScrollable", function findScrollable()
-                               let ({ buffer } = overlay.activeModules) buffer.findScrollable.apply(buffer, arguments)),
+    findScrollableWindow: deprecated("buffer.findScrollableWindow",
+                                     function findScrollableWindow() apply(overlay.activeModules, "findScrollableWindow", arguments)),
+    findScrollable: deprecated("buffer.findScrollable",
+                               function findScrollable() apply(overlay.activeModules, "findScrollable", arguments)),
 
     isScrollable: function isScrollable(elem, dir, horizontal) {
         if (!DOM(elem).isScrollable(horizontal ? "horizontal" : "vertical"))
@@ -1632,40 +1637,43 @@ var Buffer = Module("Buffer", {
      * Like scrollTo, but scrolls more smoothly and does not update
      * marks.
      */
-    smoothScrollTo: let (timers = WeakMap())
-                    function smoothScrollTo(node, x, y) {
-        let { options } = overlay.activeModules;
+    smoothScrollTo: new function () {
+        let timers = new WeakMap;
 
-        let time = options["scrolltime"];
-        let steps = options["scrollsteps"];
+        return function smoothScrollTo(node, x, y) {
+            let { options } = overlay.activeModules;
 
-        let elem = Buffer.Scrollable(node);
+            let time = options["scrolltime"];
+            let steps = options["scrollsteps"];
 
-        if (timers.has(node))
-            timers.get(node).cancel();
-
-        if (x == null)
-            x = elem.scrollLeft;
-        if (y == null)
-            y = elem.scrollTop;
-
-        x = node.dactylScrollDestX = Math.min(x, elem.scrollWidth  - elem.clientWidth);
-        y = node.dactylScrollDestY = Math.min(y, elem.scrollHeight - elem.clientHeight);
-        let [startX, startY] = [elem.scrollLeft, elem.scrollTop];
-        let n = 0;
-        (function next() {
-            if (n++ === steps) {
-                elem.scrollLeft = x;
-                elem.scrollTop  = y;
-                delete node.dactylScrollDestX;
-                delete node.dactylScrollDestY;
-            }
-            else {
-                elem.scrollLeft = startX + (x - startX) / steps * n;
-                elem.scrollTop  = startY + (y - startY) / steps * n;
-                timers.set(node, util.timeout(next, time / steps));
-            }
-        }).call(this);
+            let elem = Buffer.Scrollable(node);
+
+            if (timers.has(node))
+                timers.get(node).cancel();
+
+            if (x == null)
+                x = elem.scrollLeft;
+            if (y == null)
+                y = elem.scrollTop;
+
+            x = node.dactylScrollDestX = Math.min(x, elem.scrollWidth  - elem.clientWidth);
+            y = node.dactylScrollDestY = Math.min(y, elem.scrollHeight - elem.clientHeight);
+            let [startX, startY] = [elem.scrollLeft, elem.scrollTop];
+            let n = 0;
+            (function next() {
+                if (n++ === steps) {
+                    elem.scrollLeft = x;
+                    elem.scrollTop  = y;
+                    delete node.dactylScrollDestX;
+                    delete node.dactylScrollDestY;
+                }
+                else {
+                    elem.scrollLeft = startX + (x - startX) / steps * n;
+                    elem.scrollTop  = startY + (y - startY) / steps * n;
+                    timers.set(node, util.timeout(next, time / steps));
+                }
+            }).call(this);
+        };
     },
 
     /**
@@ -1946,7 +1954,7 @@ var Buffer = Module("Buffer", {
                     if (/^>>/.test(filename)) {
                         let file = io.File(filename.replace(/^>>\s*/, ""));
                         dactyl.assert(args.bang || file.exists() && file.isWritable(),
-                                      _("io.notWriteable", file.path.quote()));
+                                      _("io.notWriteable", JSON.stringify(file.path)));
 
                         return buffer.viewSourceExternally(buffer.focusedFrame.document,
                             function (tmpFile) {
@@ -1954,7 +1962,7 @@ var Buffer = Module("Buffer", {
                                     file.write(tmpFile, ">>");
                                 }
                                 catch (e) {
-                                    dactyl.echoerr(_("io.notWriteable", file.path.quote()));
+                                    dactyl.echoerr(_("io.notWriteable", JSON.stringify(file.path)));
                                 }
                             });
                     }
@@ -2046,13 +2054,13 @@ var Buffer = Module("Buffer", {
             context.title = ["Stylesheet", "Location"];
 
             // unify split style sheets
-            let styles = iter([s.title, []] for (s in values(buffer.alternateStyleSheets))).toObject();
+            let styles = iter([s.title, []] for (s of values(buffer.alternateStyleSheets))).toObject();
 
             buffer.alternateStyleSheets.forEach(function (style) {
                 styles[style.title].push(style.href || _("style.inline"));
             });
 
-            context.completions = [[title, href.join(", ")] for ([title, href] in Iterator(styles))];
+            context.completions = [[title, href.join(", ")] for ([title, href] of iter(styles))];
         };
 
         completion.savePage = function savePage(context, node) {
@@ -2131,7 +2139,7 @@ var Buffer = Module("Buffer", {
             "Repeat the last key event",
             function ({ count }) {
                 if (mappings.repeat) {
-                    for (let i in util.interruptibleRange(0, Math.max(count, 1), 100))
+                    for (let i of util.interruptibleRange(0, Math.max(count, 1), 100))
                         mappings.repeat();
                 }
             },
@@ -2304,7 +2312,7 @@ var Buffer = Module("Buffer", {
 
                     let frames = buffer.allFrames(null, true);
 
-                    let elements = array.flatten(frames.map(win => [m for (m in DOM.XPath(xpath, win.document))]))
+                    let elements = array.flatten(frames.map(win => [m for (m of DOM.XPath(xpath, win.document))]))
                                         .filter(function (elem) {
                         if (isinstance(elem, [Ci.nsIDOMHTMLFrameElement,
                                               Ci.nsIDOMHTMLIFrameElement]))
@@ -2450,7 +2458,7 @@ var Buffer = Module("Buffer", {
                         return val;
 
                     // Stolen from browser.jar/content/browser/browser.js, more or less.
-                    Task.spawn(function () {
+                    Task.spawn(function* () {
                         try {
                             buffer.docShell.QueryInterface(Ci.nsIDocCharset).charset = val;
                             yield window.PlacesUtils.setCharsetForURI(buffer.uri, val);
@@ -2483,7 +2491,7 @@ var Buffer = Module("Buffer", {
             {
                 keepQuotes: true,
                 setter: function (vals) {
-                    for (let [k, v] in Iterator(vals))
+                    for (let [k, v] of iter(vals))
                         vals[k] = update(new String(v), { matcher: DOM.compileMatcher(Option.splitList(v)) });
                     return vals;
                 },
@@ -2507,7 +2515,7 @@ var Buffer = Module("Buffer", {
             {
                 getLine: function getLine(doc, line) {
                     let uri = util.newURI(doc.documentURI);
-                    for (let filter in values(this.value))
+                    for (let filter of values(this.value))
                         if (filter(uri, doc)) {
                             if (/^func:/.test(filter.result))
                                 var res = dactyl.userEval("(" + Option.dequote(filter.result.substr(5)) + ")")(doc, line);
@@ -2526,7 +2534,7 @@ var Buffer = Module("Buffer", {
                 keepQuotes: true,
 
                 setter: function (vals) {
-                    for (let value in values(vals))
+                    for (let value of values(vals))
                         if (!/^func:/.test(value.result))
                             value.matcher = DOM.compileMatcher(Option.splitList(value.result));
                     return vals;
@@ -2610,16 +2618,16 @@ var Buffer = Module("Buffer", {
     }
 });
 
-Buffer.addPageInfoSection("e", "Search Engines", function (verbose) {
+Buffer.addPageInfoSection("e", "Search Engines", function* (verbose) {
     let n = 1;
     let nEngines = 0;
 
-    for (let { document: doc } in values(this.allFrames())) {
+    for (let { document: doc } of values(this.allFrames())) {
         let engines = DOM("link[href][rel=search][type='application/opensearchdescription+xml']", doc);
         nEngines += engines.length;
 
         if (verbose)
-            for (let link in engines)
+            for (let link of engines)
                 yield [link.title || /*L*/ "Engine " + n++,
                        ["a", { href: link.href, highlight: "URL",
                                onclick: "if (event.button == 0) { window.external.AddSearchProvider(this.href); return false; }" },
@@ -2630,7 +2638,7 @@ Buffer.addPageInfoSection("e", "Search Engines", function (verbose) {
         yield nEngines + /*L*/" engine" + (nEngines > 1 ? "s" : "");
 });
 
-Buffer.addPageInfoSection("f", "Feeds", function (verbose) {
+Buffer.addPageInfoSection("f", "Feeds", function* (verbose) {
     const feedTypes = {
         "application/rss+xml": "RSS",
         "application/atom+xml": "Atom",
@@ -2669,10 +2677,10 @@ Buffer.addPageInfoSection("f", "Feeds", function (verbose) {
     }
 
     let nFeed = 0;
-    for (let [i, win] in Iterator(this.allFrames())) {
+    for (let win of this.allFrames()) {
         let doc = win.document;
 
-        for (let link in DOM("link[href][rel=feed], link[href][rel=alternate][type]", doc)) {
+        for (let link of DOM("link[href][rel=feed], link[href][rel=alternate][type]", doc)) {
             let rel = link.rel.toLowerCase();
             let feed = { title: link.title, href: link.href, type: link.type || "" };
             if (isValidFeed(feed, doc.nodePrincipal, rel == "feed")) {
@@ -2690,7 +2698,7 @@ Buffer.addPageInfoSection("f", "Feeds", function (verbose) {
         yield nFeed + /*L*/" feed" + (nFeed > 1 ? "s" : "");
 });
 
-Buffer.addPageInfoSection("g", "General Info", function (verbose) {
+Buffer.addPageInfoSection("g", "General Info", function* (verbose) {
     let doc = this.focusedFrame.document;
 
     // get file size
@@ -2758,7 +2766,7 @@ Buffer.addPageInfoSection("m", "Meta Tags", function (verbose) {
                 .sort((a, b) => util.compareIgnoreCase(a[0], b[0]));
 });
 
-Buffer.addPageInfoSection("s", "Security", function (verbose) {
+Buffer.addPageInfoSection("s", "Security", function* (verbose) {
     let { statusline } = this.modules;
 
     let identity = this.topWindow.gIdentityHandler;
diff --git a/common/modules/cache.jsm b/common/modules/cache.jsm
index 398d3c9d..fbb8013d 100644
--- a/common/modules/cache.jsm
+++ b/common/modules/cache.jsm
@@ -18,8 +18,8 @@ var Cache = Module("Cache", XPCOM(Ci.nsIRequestObserver), {
         this.storage = storage.newMap("cache", { store: true });
         this.providers = {};
         this.globalProviders = this.providers;
-        this.providing = RealSet();
-        this.localProviders = RealSet();
+        this.providing = new RealSet;
+        this.localProviders = new RealSet;
 
         if (JSMLoader.cacheFlush)
             this.flush();
diff --git a/common/modules/commands.jsm b/common/modules/commands.jsm
index 0e58b6b0..297bd0e1 100644
--- a/common/modules/commands.jsm
+++ b/common/modules/commands.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -172,7 +172,7 @@ var Command = Class("Command", {
         return !dactyl.trapErrors(function exec() {
             let extra = this.hive.argsExtra(args);
 
-            for (let k in properties(extra))
+            for (let k of properties(extra))
                 if (!(k in args))
                     Object.defineProperty(args, k, Object.getOwnPropertyDescriptor(extra, k));
 
@@ -204,13 +204,14 @@ var Command = Class("Command", {
      * @returns {Args}
      * @see Commands#parseArgs
      */
-    parseArgs: function parseArgs(args, complete, extra) this.modules.commands.parseArgs(args, {
-        __proto__: this,
-        complete: complete,
-        extra: extra
-    }),
+    parseArgs: function parseArgs(args, complete, extra)
+        this.modules.commands.parseArgs(args, {
+            __proto__: this,
+            complete: complete,
+            extra: extra
+        }),
 
-    complained: Class.Memoize(function () RealSet()),
+    complained: Class.Memoize(() => new RealSet),
 
     /**
      * @property {[string]} All of this command's name specs. e.g., "com[mand]"
@@ -311,16 +312,13 @@ var Command = Class("Command", {
                 .flatten().toObject()),
 
     newArgs: function newArgs(base) {
-        let res = [];
+        let res = Object.create(this.argsPrototype);
         update(res, base);
-        res.__proto__ = this.argsPrototype;
         return res;
     },
 
     argsPrototype: Class.Memoize(function argsPrototype() {
         let res = update([], {
-                __iterator__: function AP__iterator__() array.iterItems(this),
-
                 command: this,
 
                 explicitOpts: Class.Memoize(function () ({})),
@@ -442,7 +440,7 @@ var Ex = Module("Ex", {
 
         let res = cmd.newArgs({ context: this.context });
         if (isObject(args[0]))
-            for (let [k, v] in Iterator(args.shift()))
+            for (let [k, v] of iter(args.shift()))
                 if (k == "!")
                     res.bang = v;
                 else if (k == "#")
@@ -457,18 +455,19 @@ var Ex = Module("Ex", {
                     Class.replaceProperty(res, opt.names[0], val);
                     res.explicitOpts[opt.names[0]] = val;
                 }
-        for (let [i, val] in array.iterItems(args))
+        for (let [i, val] of array.iterItems(args))
             res[i] = String(val);
         return res;
     },
 
-    _complete: function E_complete(cmd) let (self = this)
-        function _complete(context, func, obj, args) {
-            args = self._args(cmd, args);
+    _complete: function E_complete(cmd) {
+        return (context, func, obj, args) => {
+            args = this._args(cmd, args);
             args.completeArg = args.length - 1;
             if (cmd.completer && args.length)
                 return cmd.completer(context, args);
-        },
+        };
+    },
 
     _run: function E_run(name) {
         const self = this;
@@ -509,7 +508,7 @@ var CommandHive = Class("CommandHive", Contexts.Hive, {
             this.modules.moduleManager.initDependencies("commands");
 
             let map = {};
-            for (let [name, cmd] in Iterator(this._map))
+            for (let [name, cmd] of iter(this._map))
                 if (cmd.sourceModule)
                     map[name] = { sourceModule: cmd.sourceModule, isPlaceholder: true };
 
@@ -524,7 +523,7 @@ var CommandHive = Class("CommandHive", Contexts.Hive, {
         cached = cache.get(this.cacheKey);
         if (this.cached) {
             this._specs = cached.specs;
-            for (let [k, v] in Iterator(cached.map))
+            for (let [k, v] of iter(cached.map))
                 this._map[k] = v;
         }
     },
@@ -532,7 +531,7 @@ var CommandHive = Class("CommandHive", Contexts.Hive, {
     get cacheKey() "commands/hives/" + this.name + ".json",
 
     /** @property {Iterator(Command)} @private */
-    __iterator__: function __iterator__() {
+    "@@iterator": function __iterator__() {
         if (this.cached)
             this.modules.initDependencies("commands");
         this.cached = false;
@@ -577,7 +576,7 @@ var CommandHive = Class("CommandHive", Contexts.Hive, {
                         _("command.wontReplace", name));
         }
 
-        for (let name in values(names)) {
+        for (let name of values(names)) {
             ex.__defineGetter__(name, function () this._run(name));
             if (name in this._map && !this._map[name].isPlaceholder)
                 this.remove(name);
@@ -588,7 +587,7 @@ var CommandHive = Class("CommandHive", Contexts.Hive, {
         memoize(this._map, name, () => commands.Command(specs, description, action, extra));
         if (!extra.hidden)
             memoize(this._list, this._list.length, closure);
-        for (let alias in values(names.slice(1)))
+        for (let alias of values(names.slice(1)))
             memoize(this._map, alias, closure);
 
         return name;
@@ -648,7 +647,7 @@ var CommandHive = Class("CommandHive", Contexts.Hive, {
 
         let cmd = this.get(name);
         this._list = this._list.filter(c => c !== cmd);
-        for (let name in values(cmd.names))
+        for (let name of values(cmd.names))
             delete this._map[name];
     }
 });
@@ -660,144 +659,153 @@ var Commands = Module("commands", {
     lazyInit: true,
     lazyDepends: true,
 
-    Local: function Local(dactyl, modules, window) let ({ Group, contexts } = modules) ({
-        init: function init() {
-            this.Command = Class("Command", Command, { modules: modules });
-            update(this, {
-                hives: contexts.Hives("commands", Class("CommandHive", CommandHive, { modules: modules })),
-                user: contexts.hives.commands.user,
-                builtin: contexts.hives.commands.builtin
-            });
-        },
+    Local: function Local(dactyl, modules, window) {
+        let { Group, contexts } = modules;
+        return {
+            init: function init() {
+                this.Command = Class("Command", Command, { modules: modules });
+                update(this, {
+                    hives: contexts.Hives("commands", Class("CommandHive", CommandHive, { modules: modules })),
+                    user: contexts.hives.commands.user,
+                    builtin: contexts.hives.commands.builtin
+                });
+            },
 
-        reallyInit: function reallyInit() {
-            if (false)
-                this.builtin.cache();
-            else
-                this.modules.moduleManager.initDependencies("commands");
-        },
-
-        get context() contexts.context,
-
-        get readHeredoc() modules.io.readHeredoc,
-
-        get allHives() contexts.allGroups.commands,
-
-        get userHives() this.allHives.filter(h => h !== this.builtin),
-
-        /**
-         * Executes an Ex command script.
-         *
-         * @param {string} string A string containing the commands to execute.
-         * @param {object} tokens An optional object containing tokens to be
-         *      interpolated into the command string.
-         * @param {object} args Optional arguments object to be passed to
-         *      command actions.
-         * @param {object} context An object containing information about
-         *      the file that is being or has been sourced to obtain the
-         *      command string.
-         */
-        execute: function execute(string, tokens, silent, args, context) {
-            contexts.withContext(context || this.context || { file: "[Command Line]", line: 1 },
-                                 function (context) {
-                modules.io.withSavedValues(["readHeredoc"], function () {
-                    this.readHeredoc = function readHeredoc(end) {
-                        let res = [];
-                        contexts.context.line++;
-                        while (++i < lines.length) {
-                            if (lines[i] === end)
-                                return res.join("\n");
-                            res.push(lines[i]);
-                        }
-                        util.assert(false, _("command.eof", end));
-                    };
+            reallyInit: function reallyInit() {
+                if (false)
+                    this.builtin.cache();
+                else
+                    this.modules.moduleManager.initDependencies("commands");
+            },
 
-                    args = update({}, args || {});
+            get context() contexts.context,
+
+            get readHeredoc() modules.io.readHeredoc,
+
+            get allHives() contexts.allGroups.commands,
+
+            get userHives() this.allHives.filter(h => h !== this.builtin),
+
+            /**
+             * Executes an Ex command script.
+             *
+             * @param {string} string A string containing the commands to execute.
+             * @param {object} tokens An optional object containing tokens to be
+             *      interpolated into the command string.
+             * @param {object} args Optional arguments object to be passed to
+             *      command actions.
+             * @param {object} context An object containing information about
+             *      the file that is being or has been sourced to obtain the
+             *      command string.
+             */
+            execute: function execute(string, tokens, silent, args, context) {
+                contexts.withContext(context || this.context || { file: "[Command Line]", line: 1 },
+                                     function (context) {
+                    modules.io.withSavedValues(["readHeredoc"], function () {
+                        this.readHeredoc = function readHeredoc(end) {
+                            let res = [];
+                            contexts.context.line++;
+                            while (++i < lines.length) {
+                                if (lines[i] === end)
+                                    return res.join("\n");
+                                res.push(lines[i]);
+                            }
+                            util.assert(false, _("command.eof", end));
+                        };
 
-                    if (tokens && !callable(string))
-                        string = util.compileMacro(string, true);
-                    if (callable(string))
-                        string = string(tokens || {});
+                        args = update({}, args || {});
 
-                    let lines = string.split(/\r\n|[\r\n]/);
-                    let startLine = context.line;
+                        if (tokens && !callable(string))
+                            string = util.compileMacro(string, true);
+                        if (callable(string))
+                            string = string(tokens || {});
 
-                    for (var i = 0; i < lines.length && !context.finished; i++) {
-                        // Deal with editors from Silly OSs.
-                        let line = lines[i].replace(/\r$/, "");
+                        let lines = string.split(/\r\n|[\r\n]/);
+                        let startLine = context.line;
 
-                        context.line = startLine + i;
+                        for (var i = 0; i < lines.length && !context.finished; i++) {
+                            // Deal with editors from Silly OSs.
+                            let line = lines[i].replace(/\r$/, "");
 
-                        // Process escaped new lines
-                        while (i < lines.length && /^\s*\\/.test(lines[i + 1]))
-                            line += "\n" + lines[++i].replace(/^\s*\\/, "");
+                            context.line = startLine + i;
 
-                        try {
-                            dactyl.execute(line, args);
-                        }
-                        catch (e) {
-                            if (!silent) {
-                                e.message = context.file + ":" + context.line + ": " + e.message;
-                                dactyl.reportError(e, true);
+                            // Process escaped new lines
+                            while (i < lines.length && /^\s*\\/.test(lines[i + 1]))
+                                line += "\n" + lines[++i].replace(/^\s*\\/, "");
+
+                            try {
+                                dactyl.execute(line, args);
+                            }
+                            catch (e) {
+                                if (!silent) {
+                                    e.message = context.file + ":" + context.line + ": " + e.message;
+                                    dactyl.reportError(e, true);
+                                }
                             }
                         }
-                    }
+                    });
                 });
-            });
-        },
-
-        /**
-         * Lists all user-defined commands matching *filter* and optionally
-         * *hives*.
-         *
-         * @param {string} filter Limits the list to those commands with a name
-         *     matching this anchored substring.
-         * @param {[Hive]} hives List of hives.
-         * @optional
-         */
-        list: function list(filter, hives) {
-            const { commandline, completion } = this.modules;
-            function completerToString(completer) {
-                if (completer)
-                    return [k for ([k, v] in Iterator(config.completers)) if (completer == completion.bound[v])][0] || "custom";
-                return "";
+            },
+
+            /**
+             * Lists all user-defined commands matching *filter* and optionally
+             * *hives*.
+             *
+             * @param {string} filter Limits the list to those commands with a name
+             *     matching this anchored substring.
+             * @param {[Hive]} hives List of hives.
+             * @optional
+             */
+            list: function list(filter, hives) {
+                const { commandline, completion } = this.modules;
+                function completerToString(completer) {
+                    if (completer)
+                        return [k
+                                for ([k, v] of iter(config.completers))
+                                if (completer == completion.bound[v])][0] || "custom";
+
+                    return "";
+                }
+                // TODO: allow matching of aliases?
+                function cmds(hive) hive._list.filter(cmd => cmd.name.startsWith(filter || ""))
+
+                hives = (hives || this.userHives).map(h => [h, cmds(h)])
+                                                 .filter(([h, c]) => c.length);
+
+                let list = ["table", {},
+                    ["tr", { highlight: "Title" },
+                        ["td"],
+                        ["td", { style: "padding-right: 1em;" }],
+                        ["td", { style: "padding-right: 1ex;" }, _("title.Name")],
+                        ["td", { style: "padding-right: 1ex;" }, _("title.Args")],
+                        ["td", { style: "padding-right: 1ex;" }, _("title.Range")],
+                        ["td", { style: "padding-right: 1ex;" }, _("title.Complete")],
+                        ["td", { style: "padding-right: 1ex;" }, _("title.Definition")]],
+                    ["col", { style: "min-width: 6em; padding-right: 1em;" }],
+                    hives.map(([hive, cmds]) => {
+                        let i = 0;
+                        return [
+                            ["tr", { style: "height: .5ex;" }],
+                            cmds.map(cmd =>
+                                ["tr", {},
+                                    ["td", { highlight: "Title" }, !i++ ? hive.name : ""],
+                                    ["td", {}, cmd.bang ? "!" : " "],
+                                    ["td", {}, cmd.name],
+                                    ["td", {}, cmd.argCount],
+                                    ["td", {}, cmd.count ? "0c" : ""],
+                                    ["td", {}, completerToString(cmd.completer)],
+                                    ["td", {}, cmd.replacementText || "function () { ... }"]]),
+                            ["tr", { style: "height: .5ex;" }]];
+                    })];
+
+                // E4X-FIXME
+                // if (list.*.length() === list.text().length() + 2)
+                //     dactyl.echomsg(_("command.none"));
+                // else
+                commandline.commandOutput(list);
             }
-            // TODO: allow matching of aliases?
-            function cmds(hive) hive._list.filter(cmd => cmd.name.startsWith(filter || ""))
-
-            hives = (hives || this.userHives).map(h => [h, cmds(h)])
-                                             .filter(([h, c]) => c.length);
-
-            let list = ["table", {},
-                ["tr", { highlight: "Title" },
-                    ["td"],
-                    ["td", { style: "padding-right: 1em;" }],
-                    ["td", { style: "padding-right: 1ex;" }, _("title.Name")],
-                    ["td", { style: "padding-right: 1ex;" }, _("title.Args")],
-                    ["td", { style: "padding-right: 1ex;" }, _("title.Range")],
-                    ["td", { style: "padding-right: 1ex;" }, _("title.Complete")],
-                    ["td", { style: "padding-right: 1ex;" }, _("title.Definition")]],
-                ["col", { style: "min-width: 6em; padding-right: 1em;" }],
-                hives.map(([hive, cmds]) => let (i = 0) [
-                    ["tr", { style: "height: .5ex;" }],
-                    cmds.map(cmd =>
-                        ["tr", {},
-                            ["td", { highlight: "Title" }, !i++ ? hive.name : ""],
-                            ["td", {}, cmd.bang ? "!" : " "],
-                            ["td", {}, cmd.name],
-                            ["td", {}, cmd.argCount],
-                            ["td", {}, cmd.count ? "0c" : ""],
-                            ["td", {}, completerToString(cmd.completer)],
-                            ["td", {}, cmd.replacementText || "function () { ... }"]]),
-                    ["tr", { style: "height: .5ex;" }]])];
-
-            // E4X-FIXME
-            // if (list.*.length() === list.text().length() + 2)
-            //     dactyl.echomsg(_("command.none"));
-            // else
-            commandline.commandOutput(list);
-        }
-    }),
+        };
+    },
 
     /**
      * @property Indicates that no count was specified for this
@@ -850,7 +858,7 @@ var Commands = Module("commands", {
             defaults = array(this.options).map(opt => [opt.names[0], opt.default])
                                           .toObject();
 
-        for (let [opt, val] in Iterator(args.options || {})) {
+        for (let [opt, val] of iter(args.options || {})) {
             if (val === undefined)
                 continue;
             if (val != null && defaults[opt] === val)
@@ -864,7 +872,7 @@ var Commands = Module("commands", {
             res.push(opt);
         }
 
-        for (let [, arg] in Iterator(args.arguments || []))
+        for (let arg of (args.arguments || []))
             res.push(Commands.quote(arg));
 
         let str = args.literalArg;
@@ -895,7 +903,7 @@ var Commands = Module("commands", {
      */
     hasDomain: function hasDomain(command, host) {
         try {
-            for (let [cmd, args] in this.subCommands(command))
+            for (let [cmd, args] of this.subCommands(command))
                 if (Array.concat(cmd.domains(args)).some(domain => util.isSubdomain(domain, host)))
                     return true;
         }
@@ -913,7 +921,7 @@ var Commands = Module("commands", {
      * @returns {boolean}
      */
     hasPrivateData: function hasPrivateData(command) {
-        for (let [cmd, args] in this.subCommands(command))
+        for (let [cmd, args] of this.subCommands(command))
             if (cmd.privateData)
                 return !callable(cmd.privateData) ? cmd.privateData
                                                   : cmd.privateData(args);
@@ -1002,7 +1010,7 @@ var Commands = Module("commands", {
             args.string = str; // for access to the unparsed string
 
             // FIXME!
-            for (let [k, v] in Iterator(extra || []))
+            for (let [k, v] of iter(extra || {}))
                 args[k] = v;
 
             // FIXME: best way to specify these requirements?
@@ -1065,8 +1073,8 @@ var Commands = Module("commands", {
 
                 var optname = "";
                 if (!onlyArgumentsRemaining) {
-                    for (let [, opt] in Iterator(options)) {
-                        for (let [, optname] in Iterator(opt.names)) {
+                    for (let opt of options) {
+                        for (let optname of opt.names) {
                             if (sub.startsWith(optname)) {
                                 let count = 0;
                                 let invalid = false;
@@ -1166,10 +1174,10 @@ var Commands = Module("commands", {
                     sub = re.exec(str)[1];
 
                     // Hack.
-                    if (sub.substr(0, 2) === "<<" && hereDoc)
-                        let ([count, arg] = getNextArg(sub)) {
-                            sub = arg + sub.substr(count);
-                        };
+                    if (sub.substr(0, 2) === "<<" && hereDoc) {
+                        let [count, arg] = getNextArg(sub);
+                        sub = arg + sub.substr(count);
+                    }
 
                     args.push(sub);
                     args.quote = null;
@@ -1333,7 +1341,7 @@ var Commands = Module("commands", {
         return [count, cmd, !!bang, args || "", spec.length, group];
     },
 
-    parseCommands: function parseCommands(str, complete) {
+    parseCommands: function* parseCommands(str, complete) {
         const { contexts } = this.modules;
         do {
             let [count, cmd, bang, args, len, group] = commands.parseCommand(str);
@@ -1365,11 +1373,11 @@ var Commands = Module("commands", {
         while (str);
     },
 
-    subCommands: function subCommands(command) {
+    subCommands: function* subCommands(command) {
         let commands = [command];
         while (command = commands.shift())
             try {
-                for (let [command, args] in this.parseCommands(command)) {
+                for (let [command, args] of this.parseCommands(command)) {
                     if (command) {
                         yield [command, args];
                         if (command.subCommand && args[command.subCommand])
@@ -1447,7 +1455,7 @@ var Commands = Module("commands", {
 
             // if there is no space between the command name and the cursor
             // then get completions of the command name
-            for (var [command, args] in commands.parseCommands(context.filter, context))
+            for (var [command, args] of commands.parseCommands(context.filter, context))
                 if (args.trailing)
                     context.advance(args.commandString.length + 1);
             if (!args)
@@ -1622,7 +1630,7 @@ var Commands = Module("commands", {
                         // TODO: "E180: invalid complete value: " + arg
                         names: ["-complete", "-C"],
                         description: "The argument completion function",
-                        completer: function (context) [[k, ""] for ([k, v] in Iterator(config.completers))],
+                        completer: function (context) [[k, ""] for ([k, v] of iter(config.completers))],
                         type: CommandOption.STRING,
                         validator: function (arg) arg in config.completers || /^custom,/.test(arg),
                     },
@@ -1669,7 +1677,7 @@ var Commands = Module("commands", {
                             bang: true,
                             options: iter([v, typeof cmd[k] == "boolean" ? null : cmd[k]]
                                           // FIXME: this map is expressed multiple times
-                                          for ([k, v] in Iterator({
+                                          for ([k, v] of iter({
                                               argCount: "-nargs",
                                               bang: "-bang",
                                               count: "-count",
@@ -1680,7 +1688,7 @@ var Commands = Module("commands", {
                             literalArg: cmd.action,
                             ignoreDefaults: true
                         }
-                        for (cmd in hive) if (cmd.persist)
+                        for (cmd of hive) if (cmd.persist)
                     ])
                     .flatten().array
             });
@@ -1724,8 +1732,11 @@ var Commands = Module("commands", {
                                                             cmd.hive.name]
                 ]
             })),
-            iterateIndex: function (args) let (tags = help.tags)
-                this.iterate(args).filter(cmd => (cmd.hive === commands.builtin || hasOwnProperty(tags, cmd.helpTag))),
+            iterateIndex: function (args) {
+                let tags = help.tags;
+                return this.iterate(args).filter(cmd => (cmd.hive === commands.builtin ||
+                                                         hasOwnProperty(tags, cmd.helpTag)));
+            },
             format: {
                 headings: ["Command", "Group", "Description"],
                 description: function (cmd) template.linkifyHelp(cmd.description + (cmd.replacementText ? ": " + cmd.action : "")),
@@ -1755,9 +1766,9 @@ var Commands = Module("commands", {
         const { JavaScript, commands } = modules;
 
         JavaScript.setCompleter([CommandHive.prototype.get, CommandHive.prototype.remove],
-                                [function () [[c.names, c.description] for (c in this)]]);
+                                [function () [[c.names, c.description] for (c of this)]]);
         JavaScript.setCompleter([Commands.prototype.get],
-                                [function () [[c.names, c.description] for (c in this.iterator())]]);
+                                [function () [[c.names, c.description] for (c of this.iterator())]]);
     },
     mappings: function initMappings(dactyl, modules, window) {
         const { commands, mappings, modes } = modules;
@@ -1766,7 +1777,7 @@ var Commands = Module("commands", {
             ["@:"], "Repeat the last Ex command",
             function ({ count }) {
                 if (commands.repeat) {
-                    for (let i in util.interruptibleRange(0, Math.max(count, 1), 100))
+                    for (let i of util.interruptibleRange(0, Math.max(count, 1), 100))
                         dactyl.execute(commands.repeat);
                 }
                 else
diff --git a/common/modules/completion.jsm b/common/modules/completion.jsm
index 6840b231..fe96ce6b 100644
--- a/common/modules/completion.jsm
+++ b/common/modules/completion.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -304,7 +304,7 @@ var CompletionContext = Class("CompletionContext", {
             items = items.array;
         // Accept a generator
         if (!isArray(items))
-            items = [x for (x in Iterator(items || []))];
+            items = [x for (x of iter(items || []))];
         if (this._completions !== items) {
             delete this.cache.filtered;
             delete this.cache.filter;
@@ -360,14 +360,14 @@ var CompletionContext = Class("CompletionContext", {
         let self = this;
         let res = { highlight: "" };
 
-        function result(quote) {
+        function* result(quote) {
             yield ["context", function p_context() self];
             yield ["result", quote ? function p_result() quote[0] + util.trapErrors(1, quote, this.text) + quote[2]
                                    : function p_result() this.text];
             yield ["texts", function p_texts() Array.concat(this.text)];
         };
 
-        for (let i in iter(this.keys, result(this.quote))) {
+        for (let i of iter(this.keys, result(this.quote))) {
             let [k, v] = i;
             if (typeof v == "string" && /^[.[]/.test(v))
                 // This is only allowed to be a simple accessor, and shouldn't
@@ -622,7 +622,7 @@ var CompletionContext = Class("CompletionContext", {
      * sub-contexts.
      */
     cancelAll: function cancelAll() {
-        for (let [, context] in Iterator(this.contextList)) {
+        for (let context of this.contextList) {
             if (context.cancel)
                 context.cancel();
         }
@@ -670,7 +670,7 @@ var CompletionContext = Class("CompletionContext", {
         }
     },
 
-    getRows: function getRows(start, end, doc) {
+    getRows: function* getRows(start, end, doc) {
         let items = this.items;
         let cache = this.cache.rows;
         let step = start > end ? -1 : 1;
@@ -679,7 +679,7 @@ var CompletionContext = Class("CompletionContext", {
         end = Math.min(items.length, end != null ? end : items.length);
 
         this.doc = doc;
-        for (let i in util.range(start, end, step))
+        for (let i of util.range(start, end, step))
             yield [i, this.getRow(i)];
     },
 
@@ -717,8 +717,10 @@ var CompletionContext = Class("CompletionContext", {
             context.waitingForTab = true;
         else if (completer) {
             let res = completer.apply(self || this, [context].concat(args));
+
             if (res && !isArray(res) && !isArray(res.__proto__))
-                res = [k for (k in res)];
+                res = [k for (k of res)];
+
             if (res)
                 context.completions = res;
             return res;
@@ -766,6 +768,7 @@ var CompletionContext = Class("CompletionContext", {
         if (arguments.length == 0) {
             for (let type in this.selectionTypes)
                 this.highlight(0, 0, type);
+
             this.selectionTypes = {};
         }
         try {
@@ -837,7 +840,7 @@ var CompletionContext = Class("CompletionContext", {
         }
         //for (let key in (k for ([k, v] in Iterator(this.contexts)) if (v.offset > this.caret)))
         //    delete this.contexts[key];
-        for each (let context in this.contexts) {
+        for (let context of values(this.contexts)) {
             context.hasItems = false;
             context.incomplete = false;
         }
@@ -870,7 +873,7 @@ var CompletionContext = Class("CompletionContext", {
     Filter: {
         text: function F_text(item) {
             let text = item.texts;
-            for (let [i, str] in Iterator(text)) {
+            for (let [i, str] of iter(text)) {
                 if (this.match(String(str))) {
                     item.text = String(text[i]);
                     return true;
@@ -1042,7 +1045,7 @@ var Completion = Module("completion", {
                     context.incomplete = result.searchResult >= result.RESULT_NOMATCH_ONGOING;
                     context.completions = [
                         { url: result.getValueAt(i), title: result.getCommentAt(i), icon: result.getImageAt(i) }
-                        for (i in util.range(0, result.matchCount))
+                        for (i of util.range(0, result.matchCount))
                     ];
                 }),
                 get onUpdateSearchResult() this.onSearchResult
@@ -1126,7 +1129,7 @@ var Completion = Module("completion", {
                 completer: function (context) {
                     let PREFIX = "/ex/contexts";
                     context.fork("ex", 0, completion, "ex");
-                    completion.contextList = [[k.substr(PREFIX.length), v.title[0]] for ([k, v] in iter(context.contexts)) if (k.substr(0, PREFIX.length) == PREFIX)];
+                    completion.contextList = [[k.substr(PREFIX.length), v.title[0]] for ([k, v] of iter(context.contexts)) if (k.substr(0, PREFIX.length) == PREFIX)];
                 },
                 literal: 0
             });
@@ -1176,11 +1179,16 @@ var Completion = Module("completion", {
                     s: "search"
                 },
 
-                get values() values(completion.urlCompleters).toArray()
-                                .concat([let (name = k.substr(services.AUTOCOMPLETE.length))
-                                            ["native:" + name, _("autocomplete.description", name)]
-                                         for (k in Cc)
-                                         if (k.startsWith(services.AUTOCOMPLETE))]),
+                get values() {
+                    let builtin = Object.keys(Cc)
+                                        .filter(k => k.startsWith(services.AUTOCOMPLETE))
+                                        .map(key => {
+                        let name = key.substr(services.AUTOCOMPLETE.length)
+                        return ["native:" + name, _("autocomplete.description", name)];
+                    });
+
+                    return values(completion.urlCompleters).toArray().concat(builtin);
+                },
 
                 setter: function setter(values) {
                     if (values.length == 1 && !hasOwnProperty(values[0], this.values)
diff --git a/common/modules/config.jsm b/common/modules/config.jsm
index 5622126c..7ba778b3 100644
--- a/common/modules/config.jsm
+++ b/common/modules/config.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -96,7 +96,7 @@ var ConfigBase = Class("ConfigBase", {
             if (documentURL)
                 config = config.overlays && config.overlays[documentURL] || {};
 
-            for (let [name, value] in Iterator(config)) {
+            for (let [name, value] of iter(config)) {
                 let prop = util.camelCase(name);
 
                 if (isArray(this[prop]))
@@ -223,13 +223,13 @@ var ConfigBase = Class("ConfigBase", {
         if (jar) {
             let prefix = getDir(jar.JAREntry);
             var res = iter(s.slice(prefix.length).replace(/\/.*/, "")
-                           for (s in io.listJar(jar.JARFile, prefix)))
+                           for (s of io.listJar(jar.JARFile, prefix)))
                         .toArray();
         }
         else {
             res = array(f.leafName
-                        // Fails on FF3: for (f in util.getFile(uri).iterDirectory())
-                        for (f in values(util.getFile(uri).readDirectory()))
+                        // Fails on FF3: for (f of util.getFile(uri).iterDirectory())
+                        for (f of util.getFile(uri).readDirectory())
                         if (f.isDirectory())).array;
         }
 
@@ -250,7 +250,7 @@ var ConfigBase = Class("ConfigBase", {
     bestLocale: function (list) {
         return values([this.appLocale, this.appLocale.replace(/-.*/, ""),
                        "en", "en-US", list[0]])
-            .find(bind("has", RealSet(list)));
+            .find(bind("has", new RealSet(list)));
     },
 
     /**
@@ -281,19 +281,19 @@ var ConfigBase = Class("ConfigBase", {
         for (let dir of ["UChrm", "AChrom"]) {
             dir = File(services.directory.get(dir, Ci.nsIFile));
             if (dir.exists() && dir.isDirectory())
-                for (let file in dir.iterDirectory())
+                for (let file of dir.iterDirectory())
                     if (/\.manifest$/.test(file.leafName))
                         process(file.read());
 
             dir = File(dir.parent);
             if (dir.exists() && dir.isDirectory())
-                for (let file in dir.iterDirectory())
+                for (let file of dir.iterDirectory())
                     if (/\.jar$/.test(file.leafName))
                         processJar(file);
 
             dir = dir.child("extensions");
             if (dir.exists() && dir.isDirectory())
-                for (let ext in dir.iterDirectory()) {
+                for (let ext of dir.iterDirectory()) {
                     if (/\.xpi$/.test(ext.leafName))
                         processJar(ext);
                     else {
@@ -316,10 +316,13 @@ var ConfigBase = Class("ConfigBase", {
      * @param {string} max The maximum required version. @optional
      * @returns {boolean}
      */
-    haveGecko: function (min, max) let ({ compare } = services.versionCompare,
-                                        { platformVersion } = services.runtime)
-        (min == null || compare(platformVersion, min) >= 0) &&
-        (max == null || compare(platformVersion, max) < 0),
+    haveGecko: function (min, max) {
+        let { compare } = services.versionCompare;
+        let { platformVersion } = services.runtime;
+
+        return (min == null || compare(platformVersion, min) >= 0) &&
+               (max == null || compare(platformVersion, max) < 0);
+    },
 
     /** Dactyl's notion of the current operating system platform. */
     OS: memoize({
@@ -377,7 +380,7 @@ var ConfigBase = Class("ConfigBase", {
         // without explicitly selecting a profile.
 
         let dir = services.directory.get("ProfD", Ci.nsIFile);
-        for (let prof in iter(services.profile.profiles))
+        for (let prof of iter(services.profile.profiles))
             if (prof.QueryInterface(Ci.nsIToolkitProfile).rootDir.path === dir.path)
                 return prof.name;
         return "unknown";
@@ -404,7 +407,7 @@ var ConfigBase = Class("ConfigBase", {
 
     dtd: Class.Memoize(function ()
         iter(this.dtdExtra,
-             (["dactyl." + k, v] for ([k, v] in iter(config.dtdDactyl))),
+             (["dactyl." + k, v] for ([k, v] of iter(config.dtdDactyl))),
              (["dactyl." + s, config[s]] for (s of config.dtdStrings)))
             .toObject()),
 
@@ -447,7 +450,7 @@ var ConfigBase = Class("ConfigBase", {
     helpStyles: /^(Help|StatusLine|REPL)|^(Boolean|Dense|Indicator|MoreMsg|Number|Object|Logo|Key(word)?|String)$/,
     styleHelp: function styleHelp() {
         if (!this.helpStyled) {
-            for (let k in keys(highlight.loaded))
+            for (let k of keys(highlight.loaded))
                 if (this.helpStyles.test(k))
                     highlight.loaded[k] = true;
         }
@@ -462,7 +465,7 @@ var ConfigBase = Class("ConfigBase", {
                     ["menupopup", { id: "viewSidebarMenu", xmlns: "xul" }],
                     ["broadcasterset", { id: "mainBroadcasterSet", xmlns: "xul" }]];
 
-            for (let [id, [name, key, uri]] in Iterator(this.sidebars)) {
+            for (let [id, [name, key, uri]] of iter(this.sidebars)) {
                 append[0].push(
                         ["menuitem", { observes: "pentadactyl-" + id + "Sidebar", label: name,
                                        accesskey: key }]);
@@ -543,7 +546,7 @@ var ConfigBase = Class("ConfigBase", {
      *    dactyl.has(feature) to check for a feature's presence
      *    in this array.
      */
-    features: RealSet(["default-theme"]),
+    features: new RealSet(["default-theme"]),
 
     /**
      * @property {string} The file extension used for command script files.
diff --git a/common/modules/contexts.jsm b/common/modules/contexts.jsm
index 8af3e919..1eed3b5f 100644
--- a/common/modules/contexts.jsm
+++ b/common/modules/contexts.jsm
@@ -35,18 +35,18 @@ var Group = Class("Group", {
     modifiable: true,
 
     cleanup: function cleanup(reason) {
-        for (let hive in values(this.hives))
+        for (let hive of values(this.hives))
             util.trapErrors("cleanup", hive);
 
         this.hives = [];
-        for (let hive in keys(this.hiveMap))
+        for (let hive of keys(this.hiveMap))
             delete this[hive];
 
         if (reason != "shutdown")
             this.children.splice(0).forEach(this.contexts.bound.removeGroup);
     },
     destroy: function destroy(reason) {
-        for (let hive in values(this.hives))
+        for (let hive of values(this.hives))
             util.trapErrors("destroy", hive);
 
         if (reason != "shutdown")
@@ -66,20 +66,25 @@ var Group = Class("Group", {
 
 }, {
     compileFilter: function (patterns, default_=false) {
-        function siteFilter(uri)
-            let (match = siteFilter.filters.find(f => f(uri)))
-                match ? match.result
-                      : default_;
+        function siteFilter(uri) {
+            let match = siteFilter.filters.find(f => f(uri));
+            return match ? match.result
+                         : default_;
+        }
 
         return update(siteFilter, {
             toString: function () this.filters.join(","),
 
-            toJSONXML: function (modules) let (uri = modules && modules.buffer.uri)
-                template.map(this.filters,
-                             f => ["span", { highlight: uri && f(uri) ? "Filter" : "" },
-                                       ("toJSONXML" in f ? f.toJSONXML()
-                                                         : String(f))],
-                             ","),
+            toJSONXML: function (modules) {
+                let uri = modules && modules.buffer.uri;
+
+                return template.map(
+                    this.filters,
+                    f => ["span", { highlight: uri && f(uri) ? "Filter" : "" },
+                              ("toJSONXML" in f ? f.toJSONXML()
+                                                : String(f))],
+                    ",");
+            },
 
             filters: Option.parse.sitelist(patterns)
         });
@@ -94,7 +99,7 @@ var Contexts = Module("contexts", {
     },
 
     cleanup: function () {
-        for each (let module in this.pluginModules)
+        for (let module of values(this.pluginModules))
             util.trapErrors("unload", module);
 
         this.pluginModules = {};
@@ -152,7 +157,7 @@ var Contexts = Module("contexts", {
             for (let hive of values(this.groupList.slice()))
                 util.trapErrors("destroy", hive, "shutdown");
 
-            for each (let plugin in this.modules.plugins.contexts) {
+            for (let plugin of values(this.modules.plugins.contexts)) {
                 if (plugin && "onUnload" in plugin && callable(plugin.onUnload))
                     util.trapErrors("onUnload", plugin);
 
@@ -195,7 +200,7 @@ var Contexts = Module("contexts", {
 
                 memoize(contexts.groupsProto, name,
                         function () [group[name]
-                                     for (group in values(this.groups))
+                                     for (group of values(this.groups))
                                      if (hasOwnProperty(group, name))]);
             },
 
@@ -413,9 +418,12 @@ var Contexts = Module("contexts", {
         delete this.allGroups;
     },
 
-    initializedGroups: function (hive)
-        let (need = hive ? [hive] : Object.keys(this.hives))
-            this.groupList.filter(group => need.some(hasOwnProperty.bind(null, group))),
+    initializedGroups: function (hive) {
+        let need = hive ? [hive]
+                        : Object.keys(this.hives);
+
+        return this.groupList.filter(group => need.some(hasOwnProperty.bind(null, group)));
+    },
 
     addGroup: function addGroup(name, description, filter, persist, replace) {
         let group = this.getGroup(name);
@@ -502,13 +510,18 @@ var Contexts = Module("contexts", {
         let process = util.identity;
 
         if (callable(params))
-            var makeParams = function makeParams(self, args)
-                let (obj = params.apply(self, args))
-                    iter.toObject([k, Proxy(obj, k)] for (k in properties(obj)));
+            var makeParams = function makeParams(self, args) {
+                let obj = params.apply(self, args);
+
+                return iter.toObject([k, Proxy(obj, k)]
+                                     for (k of properties(obj)));
+            };
+
         else if (params)
-            makeParams = function makeParams(self, args)
-                iter.toObject([name, process(args[i])]
-                              for ([i, name] in Iterator(params)));
+            makeParams = function makeParams(self, args) {
+                return iter.toObject([name, process(args[i])]
+                                     for ([i, name] of iter(params)));
+            };
 
         let rhs = args.literalArg;
         let type = ["-builtin", "-ex", "-javascript", "-keys"].reduce((a, b) => args[b] ? b : a, default_);
@@ -684,7 +697,7 @@ var Contexts = Module("contexts", {
                         bang: true,
                         options: iter([v, typeof group[k] == "boolean" ? null : group[k]]
                                       // FIXME: this map is expressed multiple times
-                                      for ([k, v] in Iterator({
+                                      for ([k, v] of iter({
                                           args: "-args",
                                           description: "-description",
                                           filter: "-locations"
@@ -693,7 +706,7 @@ var Contexts = Module("contexts", {
                         arguments: [group.name],
                         ignoreDefaults: true
                     }
-                    for (group in values(contexts.initializedGroups()))
+                    for (group of values(contexts.initializedGroups()))
                     if (!group.builtin && group.persist)
                 ].concat([{ command: this.name, arguments: ["user"] }])
             });
diff --git a/common/modules/dom.jsm b/common/modules/dom.jsm
index 72d80135..5a4d2598 100644
--- a/common/modules/dom.jsm
+++ b/common/modules/dom.jsm
@@ -1,5 +1,5 @@
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -63,7 +63,10 @@ var DOM = Class("DOM", {
         }
         else if (val instanceof Ci.nsIDOMNode || val instanceof Ci.nsIDOMWindow)
             this[length++] = val;
-        else if ("__iterator__" in val || isinstance(val, ["Iterator", "Generator"]))
+        else if (Symbol.iterator in val)
+            for (let elem of val)
+                this[length++] = elem;
+        else if (isinstance(val, ["Iterator", "Generator"]))
             for (let elem in val)
                 this[length++] = elem;
         else if ("length" in val)
@@ -76,7 +79,7 @@ var DOM = Class("DOM", {
         return self || this;
     },
 
-    __iterator__: function __iterator__() {
+    "@@iterator": function* __iterator__() {
         for (let i = 0; i < this.length; i++)
             yield this[i];
     },
@@ -85,20 +88,21 @@ var DOM = Class("DOM", {
 
     nodes: Class.Memoize(function () ({})),
 
-    get items() {
+    get items() (function* () {
         for (let i = 0; i < this.length; i++)
+            /* FIXME: Symbols */
             yield this.eq(i);
-    },
+    })(),
 
     get document() this._document || this[0] && (this[0].ownerDocument || this[0].document || this[0]),
     set document(val) this._document = val,
 
     attrHooks: array.toObject([
         ["", {
-            href: { get: function (elem) elem.href || elem.getAttribute("href") },
-            src:  { get: function (elem) elem.src || elem.getAttribute("src") },
-            checked: { get: function (elem) elem.hasAttribute("checked") ? elem.getAttribute("checked") == "true" : elem.checked,
-                       set: function (elem, val) { elem.setAttribute("checked", !!val); elem.checked = val; } },
+            href: { get: elem => elem.href || elem.getAttribute("href") },
+            src:  { get: elem => elem.src || elem.getAttribute("src") },
+            checked: { get: elem => elem.hasAttribute("checked") ? elem.getAttribute("checked") == "true" : elem.checked,
+                       set: (elem, val) => { elem.setAttribute("checked", !!val); elem.checked = val; } },
             collapsed: BooleanAttribute("collapsed"),
             disabled: BooleanAttribute("disabled"),
             hidden: BooleanAttribute("hidden"),
@@ -261,58 +265,71 @@ var DOM = Class("DOM", {
     get allSiblingsBefore() this.all(elem => elem.previousSibling),
     get allSiblingsAfter() this.all(elem => elem.nextSibling),
 
-    get class() let (self = this) ({
-        toString: function () self[0].className,
+    get class() {
+        let self = this;
 
-        get list() Array.slice(self[0].classList),
-        set list(val) self.attr("class", val.join(" ")),
+        return {
+            toString: function () self[0].className,
 
-        each: function each(meth, arg) {
-            return self.each(function (elem) {
-                elem.classList[meth](arg);
-            });
-        },
+            get list() Array.slice(self[0].classList),
+            set list(val) self.attr("class", val.join(" ")),
 
-        add: function add(cls) this.each("add", cls),
-        remove: function remove(cls) this.each("remove", cls),
-        toggle: function toggle(cls, val, thisObj) {
-            if (callable(val))
-                return self.each(function (elem, i) {
-                    this.class.toggle(cls, val.call(thisObj || this, elem, i));
+            each: function each(meth, arg) {
+                return self.each(function (elem) {
+                    elem.classList[meth](arg);
                 });
-            return this.each(val == null ? "toggle" : val ? "add" : "remove", cls);
-        },
+            },
+
+            add: function add(cls) this.each("add", cls),
+            remove: function remove(cls) this.each("remove", cls),
+            toggle: function toggle(cls, val, thisObj) {
+                if (callable(val))
+                    return self.each(function (elem, i) {
+                        this.class.toggle(cls, val.call(thisObj || this, elem, i));
+                    });
+                return this.each(val == null ? "toggle" : val ? "add" : "remove", cls);
+            },
 
-        has: function has(cls) this[0].classList.has(cls)
-    }),
+            has: function has(cls) this[0].classList.has(cls)
+        };
+    },
 
-    get highlight() let (self = this) ({
-        toString: function () self.attrNS(NS, "highlight") || "",
+    get highlight() {
+        let self = this;
 
-        get list() let (s = this.toString().trim()) s ? s.split(/\s+/) : [],
-        set list(val) {
-            let str = array.uniq(val).join(" ").trim();
-            self.attrNS(NS, "highlight", str || null);
-        },
+        return {
+            toString: function () self.attrNS(NS, "highlight") || "",
 
-        has: function has(hl) ~this.list.indexOf(hl),
+            get list() {
+                let s = this.toString().trim();
 
-        add: function add(hl) self.each(function () {
-            highlight.loaded[hl] = true;
-            this.highlight.list = this.highlight.list.concat(hl);
-        }),
+                return s ? s.split(/\s+/) : [];
+            },
 
-        remove: function remove(hl) self.each(function () {
-            this.highlight.list = this.highlight.list.filter(h => h != hl);
-        }),
+            set list(val) {
+                let str = array.uniq(val).join(" ").trim();
+                self.attrNS(NS, "highlight", str || null);
+            },
 
-        toggle: function toggle(hl, val, thisObj) self.each(function (elem, i) {
-            let { highlight } = this;
-            let v = callable(val) ? val.call(thisObj || this, elem, i) : val;
+            has: function has(hl) ~this.list.indexOf(hl),
 
-            highlight[(v == null ? highlight.has(hl) : !v) ? "remove" : "add"](hl);
-        }),
-    }),
+            add: function add(hl) self.each(function () {
+                highlight.loaded[hl] = true;
+                this.highlight.list = this.highlight.list.concat(hl);
+            }),
+
+            remove: function remove(hl) self.each(function () {
+                this.highlight.list = this.highlight.list.filter(h => h != hl);
+            }),
+
+            toggle: function toggle(hl, val, thisObj) self.each(function (elem, i) {
+                let { highlight } = this;
+                let v = callable(val) ? val.call(thisObj || this, elem, i) : val;
+
+                highlight[(v == null ? highlight.has(hl) : !v) ? "remove" : "add"](hl);
+            }),
+        };
+    },
 
     get rect() this[0] instanceof Ci.nsIDOMWindow ? { width: this[0].scrollMaxX + this[0].innerWidth,
                                                       height: this[0].scrollMaxY + this[0].innerHeight,
@@ -496,7 +513,7 @@ var DOM = Class("DOM", {
         if (field instanceof Ci.nsIDOMHTMLInputElement && field.type == "submit")
             elems.push(encode(field.name, field.value));
 
-        for (let [, elem] in iter(form.elements))
+        for (let elem of form.elements)
             if (elem.name && !elem.disabled) {
                 if (DOM(elem).isInput
                         || /^(?:hidden|textarea)$/.test(elem.type)
@@ -511,7 +528,7 @@ var DOM = Class("DOM", {
                         elems.push(encode(elem.name, "", true));
                 }
                 else if (elem instanceof Ci.nsIDOMHTMLSelectElement) {
-                    for (let [, opt] in Iterator(elem.options))
+                    for (let opt of elem.options)
                         if (opt.selected)
                             elems.push(encode(elem.name, opt.value));
                 }
@@ -596,7 +613,7 @@ var DOM = Class("DOM", {
                 else {
                     let tag = "<" + [namespaced(elem)].concat(
                         [namespaced(a) + '="' + String.replace(a.value, /["<]/, DOM.escapeHTML) + '"'
-                         for ([i, a] in array.iterItems(elem.attributes))]).join(" ");
+                     for ([i, a] of array.iterItems(elem.attributes))]).join(" ");
 
                     res.push(tag + (!hasChildren ? "/>" : ">...</" + namespaced(elem) + ">"));
                 }
@@ -621,7 +638,7 @@ var DOM = Class("DOM", {
 
         if (isObject(key))
             return this.each(function (elem, i) {
-                for (let [k, v] in Iterator(key)) {
+                for (let [k, v] of iter(key)) {
                     if (callable(v))
                         v = v.call(this, elem, i);
 
@@ -652,7 +669,7 @@ var DOM = Class("DOM", {
 
         if (isObject(key))
             return this.each(function (elem) {
-                for (let [k, v] in Iterator(key))
+                for (let [k, v] of iter(key))
                     elem.style[css.property(k)] = v;
             });
 
@@ -789,20 +806,20 @@ var DOM = Class("DOM", {
         }, this);
     },
 
-    html: function html(txt, self) {
-        return this.getSet(arguments,
+    html: function html(...args) {
+        return this.getSet(args,
                            elem => elem.innerHTML,
                            util.wrapCallback((elem, val) => { elem.innerHTML = val; }));
     },
 
-    text: function text(txt, self) {
-        return this.getSet(arguments,
+    text: function text(...args) {
+        return this.getSet(args,
                            elem => elem.textContent,
                            (elem, val) => { elem.textContent = val; });
     },
 
-    val: function val(txt) {
-        return this.getSet(arguments,
+    val: function val(...args) {
+        return this.getSet(args,
                            elem => elem.value,
                            (elem, val) => { elem.value = val == null ? "" : val; });
     },
@@ -813,11 +830,11 @@ var DOM = Class("DOM", {
         else
             event = array.toObject([[event, listener]]);
 
-        for (let [evt, callback] in Iterator(event))
+        for (let [evt, callback] of iter(event))
             event[evt] = util.wrapCallback(callback, true);
 
         return this.each(function (elem) {
-            for (let [evt, callback] in Iterator(event))
+            for (let [evt, callback] of iter(event))
                 elem.addEventListener(evt, callback, capture);
         });
     },
@@ -828,7 +845,7 @@ var DOM = Class("DOM", {
             event = array.toObject([[event, listener]]);
 
         return this.each(function (elem) {
-            for (let [k, v] in Iterator(event))
+            for (let [k, v] of iter(event))
                 elem.removeEventListener(k, v.wrapper || v, capture);
         });
     },
@@ -838,7 +855,7 @@ var DOM = Class("DOM", {
         else
             event = array.toObject([[event, listener]]);
 
-        for (let pair in Iterator(event)) {
+        for (let pair of iter(event)) {
             let [evt, callback] = pair;
             event[evt] = util.wrapCallback(function wrapper(event) {
                 this.removeEventListener(evt, wrapper.wrapper, capture);
@@ -847,7 +864,7 @@ var DOM = Class("DOM", {
         }
 
         return this.each(function (elem) {
-            for (let [k, v] in Iterator(event))
+            for (let [k, v] of iter(event))
                 elem.addEventListener(k, v, capture);
         });
     },
@@ -926,7 +943,7 @@ var DOM = Class("DOM", {
                 }
             }
 
-            for (let parent in this.ancestors.items)
+            for (let parent of this.ancestors.items)
                 fix(parent);
 
             fix(DOM(this.document.defaultView));
@@ -981,9 +998,16 @@ var DOM = Class("DOM", {
             let params = DEFAULTS[t || "HTML"];
             let args = Object.keys(params);
             update(params, this.constructor.defaults[type],
-                   iter.toObject([k, opts[k]] for (k in opts) if (k in params)));
+                   iter.toObject([k, opts[k]]
+                                 for (k in opts)
+                                 if (k in params)));
 
-            evt["init" + t + "Event"].apply(evt, args.map(k => params[k]));
+            // Because security boundaries :/
+            let ary = new doc.defaultView.Array;
+            for (let arg of args)
+                ary.push(params[arg]);
+
+            evt["init" + t + "Event"].apply(evt, ary);
             return evt;
         }
     }, {
@@ -1024,14 +1048,14 @@ var DOM = Class("DOM", {
             this.key_code = {};
             this.code_nativeKey = {};
 
-            for (let list in values(this.keyTable))
-                for (let v in values(list)) {
+            for (let list of values(this.keyTable))
+                for (let v of values(list)) {
                     if (v.length == 1)
                         v = v.toLowerCase();
                     this.key_key[v.toLowerCase()] = v;
                 }
 
-            for (let [k, v] in Iterator(Ci.nsIDOMKeyEvent)) {
+            for (let [k, v] of iter(Ci.nsIDOMKeyEvent)) {
                 if (!/^DOM_VK_/.test(k))
                     continue;
 
@@ -1048,7 +1072,7 @@ var DOM = Class("DOM", {
                     names = this.keyTable[k];
 
                 this.code_key[v] = names[0];
-                for (let [, name] in Iterator(names)) {
+                for (let name of names) {
                     this.key_key[name.toLowerCase()] = name;
                     this.key_code[name.toLowerCase()] = v;
                 }
@@ -1069,7 +1093,7 @@ var DOM = Class("DOM", {
         keyTable:       Class.Memoize(function (prop) this.init()[prop]),
         key_code:       Class.Memoize(function (prop) this.init()[prop]),
         key_key:        Class.Memoize(function (prop) this.init()[prop]),
-        pseudoKeys:     RealSet(["count", "leader", "nop", "pass"]),
+        pseudoKeys:     new RealSet(["count", "leader", "nop", "pass"]),
 
         /**
          * Converts a user-input string of keys into a canonical
@@ -1095,11 +1119,13 @@ var DOM = Class("DOM", {
             return this.parse(keys, unknownOk).map(this.bound.stringify).join("");
         },
 
-        iterKeys: function iterKeys(keys) iter(function () {
-            let match, re = /<.*?>?>|[^<]/g;
-            while (match = re.exec(keys))
-                yield match[0];
-        }()),
+        iterKeys: function iterKeys(keys) {
+            return iter(function* () {
+                let match, re = /<.*?>?>|[^<]/g;
+                while (match = re.exec(keys))
+                    yield match[0];
+            }());
+        },
 
         /**
          * Converts an event string into an array of pseudo-event objects.
@@ -1126,7 +1152,7 @@ var DOM = Class("DOM", {
                 return array.flatten(input.map(k => this.parse(k, unknownOk)));
 
             let out = [];
-            for (let match in util.regexp.iterate(/<.*?>?>|[^<]|<(?!.*>)/g, input)) {
+            for (let match of util.regexp.iterate(/<.*?>?>|[^<]|<(?!.*>)/g, input)) {
                 let evt_str = match[0];
 
                 let evt_obj = { ctrlKey: false, shiftKey: false, altKey: false, metaKey: false,
@@ -1139,7 +1165,7 @@ var DOM = Class("DOM", {
                 }
                 else {
                     let [match, modifier, keyname] = evt_str.match(/^<((?:[*12CASM⌘]-)*)(.+?)>$/i) || [false, '', ''];
-                    modifier = RealSet(modifier.toUpperCase());
+                    modifier = new RealSet(modifier.toUpperCase());
                     keyname = keyname.toLowerCase();
                     evt_obj.dactylKeyname = keyname;
                     if (/^u[0-9a-f]+$/.test(keyname))
@@ -1286,8 +1312,10 @@ var DOM = Class("DOM", {
                         // or if the shift has been forced for a non-alphabetical character by the user while :map-ping
                         if (key !== key.toLowerCase() && (event.ctrlKey || event.altKey || event.metaKey) || event.dactylShift)
                             modifier += "S-";
-                        if (/^\s$/.test(key))
-                            key = let (s = charCode.toString(16)) "U" + "0000".substr(4 - s.length) + s;
+                        if (/^\s$/.test(key)) {
+                            let s = charCode.toString(16);
+                            key = "U" + "0000".substr(4 - s.length) + s;
+                        }
                         else if (modifier.length == 0)
                             return key;
                     }
@@ -1396,9 +1424,9 @@ var DOM = Class("DOM", {
      * The set of input element type attribute values that mark the element as
      * an editable field.
      */
-    editableInputs: RealSet(["date", "datetime", "datetime-local", "email", "file",
-                             "month", "number", "password", "range", "search",
-                             "tel", "text", "time", "url", "week"]),
+    editableInputs: new RealSet(["date", "datetime", "datetime-local", "email", "file",
+                                 "month", "number", "password", "range", "search",
+                                 "tel", "text", "time", "url", "week"]),
 
     /**
      * Converts a given DOM Node, Range, or Selection to a string. If
@@ -1450,20 +1478,20 @@ var DOM = Class("DOM", {
      */
     compileMatcher: function compileMatcher(list) {
         let xpath = [], css = [];
-        for (let elem in values(list))
+        for (let elem of values(list))
             if (/^xpath:/.test(elem))
                 xpath.push(elem.substr(6));
             else
                 css.push(elem);
 
         return update(
-            function matcher(node) {
+            function* matcher(node) {
                 if (matcher.xpath)
-                    for (let elem in DOM.XPath(matcher.xpath, node))
+                    for (let elem of DOM.XPath(matcher.xpath, node))
                         yield elem;
 
                 if (matcher.css)
-                    for (let [, elem] in iter(util.withProperErrors("querySelectorAll", node, matcher.css)))
+                    for (let [, elem] of iter(util.withProperErrors("querySelectorAll", node, matcher.css)))
                         yield elem;
             }, {
                 css: css.join(", "),
@@ -1614,11 +1642,11 @@ var DOM = Class("DOM", {
     toPrettyXML: function toPrettyXML(xml, asXML, indent, namespaces) {
         const INDENT = indent || "    ";
 
-        const EMPTY = RealSet("area base basefont br col frame hr img input isindex link meta param"
-                            .split(" "));
+        const EMPTY = new RealSet("area base basefont br col frame hr img input isindex link meta param"
+                                  .split(" "));
 
         function namespaced(namespaces, namespace, localName) {
-            for (let [k, v] in Iterator(namespaces))
+            for (let [k, v] of iter(namespaces))
                 if (v == namespace)
                     return (k ? k + ":" + localName : localName);
 
@@ -1631,10 +1659,12 @@ var DOM = Class("DOM", {
             return args.some(a => (isString(a) || isFragment(a) && hasString(a)));
         }
 
+        const STRING_TYPES = ["String", "Number", "Boolean", _, DOM.DOMString];
+
         function isStrings(args) {
             if (!isArray(args))
                 return util.dump("ARGS: " + {}.toString.call(args) + " " + args), false;
-            return args.every(a => (isinstance(a, ["String", DOM.DOMString]) || isFragment(a) && isStrings(a)));
+            return args.every(a => (isinstance(a, STRING_TYPES) || isFragment(a) && isStrings(a)));
         }
 
         function tag(args, namespaces, indent) {
@@ -1643,7 +1673,7 @@ var DOM = Class("DOM", {
             if (args == "")
                 return "";
 
-            if (isinstance(args, ["String", "Number", "Boolean", _, DOM.DOMString]))
+            if (isinstance(args, STRING_TYPES))
                 return indent +
                        DOM.escapeHTML(String(args), true);
 
@@ -1717,7 +1747,7 @@ var DOM = Class("DOM", {
 
             let res = [indent, "<", name];
 
-            for (let [key, val] in Iterator(attr)) {
+            for (let [key, val] of iter(attr)) {
                 if (hasOwnProperty(skipAttr, key))
                     continue;
 
@@ -1813,10 +1843,18 @@ var DOM = Class("DOM", {
                     get resultType() result.resultType,
                     get snapshotLength() result.snapshotLength,
                     snapshotItem: function (i) result.snapshotItem(i),
-                    __iterator__:
-                        asIterator ? function () { let elem; while ((elem = this.iterateNext())) yield elem; }
-                                   : function () { for (let i = 0; i < this.snapshotLength; i++) yield this.snapshotItem(i); }
-                };
+                }
+                if (asIterator)
+                    res[Symbol.iterator] = function* () {
+                        let elem;
+                        while ((elem = this.iterateNext()))
+                            yield elem;
+                    };
+                else
+                    res[Symbol.iterator] = function* () {
+                        for (let i = 0; i < this.snapshotLength; i++)
+                            yield this.snapshotItem(i);
+                    };
                 return res;
             }
             catch (e) {
diff --git a/common/modules/downloads.jsm b/common/modules/downloads.jsm
index 3f4a3501..3f39e5ff 100644
--- a/common/modules/downloads.jsm
+++ b/common/modules/downloads.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2011-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2011-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -19,7 +19,7 @@ var MAX_LOAD_TIME = 10 * 1000;
 
 let prefix = "DOWNLOAD_";
 var states = iter([v, k.slice(prefix.length).toLowerCase()]
-                  for ([k, v] in Iterator(Ci.nsIDownloadManager))
+                  for ([k, v] of iter(Ci.nsIDownloadManager))
                   if (k.startsWith(prefix)))
                 .toObject();
 
@@ -78,13 +78,16 @@ var Download = Class("Download", {
 
     inState: function inState(states) states.indexOf(this.status) >= 0,
 
-    allowedCommands: Class.Memoize(function () let (self = this) ({
-        get delete() !self.active && (self.targetFile.exists() || self.hasPartialData),
-        get launch() self.targetFile.exists() && self.succeeded,
-        get stop()  self.active,
-        get remove() !self.active,
-        get resume() self.canceled
-    })),
+    allowedCommands: Class.Memoize(function () {
+        let self = this;
+        return {
+            get delete() !self.active && (self.targetFile.exists() || self.hasPartialData),
+            get launch() self.targetFile.exists() && self.succeeded,
+            get stop()  self.active,
+            get remove() !self.active,
+            get resume() self.canceled
+        };
+    }),
 
     command: function command(name) {
         util.assert(hasOwnProperty(this.allowedCommands, name), _("download.unknownCommand"));
@@ -95,7 +98,7 @@ var Download = Class("Download", {
     },
 
     commands: {
-        delete: promises.task(function delete_() {
+        delete: promises.task(function* delete_() {
             if (this.hasPartialData)
                 yield this.removePartialData();
             else if (this.targetFile.exists())
@@ -133,7 +136,7 @@ var Download = Class("Download", {
         resume: function resume() {
             this.download.start();
         },
-        remove: promises.task(function remove() {
+        remove: promises.task(function* remove() {
             yield this.list.list.remove(this.download);
             yield this.download.finalize(true);
         }),
@@ -201,7 +204,7 @@ var Download = Class("Download", {
         this.nodes.row.setAttribute("status", this.status);
         this.nodes.state.textContent = util.capitalize(this.status);
 
-        for (let node in values(this.nodes))
+        for (let node of values(this.nodes))
             if (node.update)
                 node.update();
 
@@ -266,7 +269,7 @@ var DownloadList = Class("DownloadList",
         this.index = Array.indexOf(this.nodes.list.childNodes,
                                    this.nodes.head);
 
-        Task.spawn(function () {
+        Task.spawn(function* () {
             this.list = yield Downloads.getList(Downloads.ALL);
 
             let start = Date.now();
@@ -312,9 +315,12 @@ var DownloadList = Class("DownloadList",
             this.cleanup();
     },
 
-    allowedCommands: Class.Memoize(function () let (self = this) ({
-        get clear() iter(self.downloads.values()).some(dl => dl.allowedCommands.remove)
-    })),
+    allowedCommands: Class.Memoize(function () {
+        let self = this;
+        return {
+            get clear() iter(self.downloads.values()).some(dl => dl.allowedCommands.remove)
+        };
+    }),
 
     commands: {
         clear: function () {
@@ -325,7 +331,7 @@ var DownloadList = Class("DownloadList",
     sort: function sort() {
         let list = iter(this.downloads.values()).sort((a, b) => a.compare(b));
 
-        for (let [i, download] in iter(list))
+        for (let [i, download] of iter(list))
             if (this.nodes.list.childNodes[i + 1] != download.nodes.row)
                 this.nodes.list.insertBefore(download.nodes.row,
                                              this.nodes.list.childNodes[i + 1]);
@@ -334,7 +340,7 @@ var DownloadList = Class("DownloadList",
     shouldSort: function shouldSort() Array.some(arguments, val => this.sortOrder.some(v => v.substr(1) == val)),
 
     update: function update() {
-        for (let node in values(this.nodes))
+        for (let node of values(this.nodes))
             if (node.update && node.update != update)
                 node.update();
         this.updateProgress();
@@ -351,7 +357,7 @@ var DownloadList = Class("DownloadList",
         let active    = downloads.filter(d => d.active);
 
         let self = Object.create(this);
-        for (let prop in values(["currentBytes", "totalBytes", "speed", "timeRemaining"]))
+        for (let prop of values(["currentBytes", "totalBytes", "speed", "timeRemaining"]))
             this[prop] = active.reduce((acc, dl) => dl[prop] + acc, 0);
 
         this.hasProgress = active.every(d => d.hasProgress);
@@ -362,7 +368,7 @@ var DownloadList = Class("DownloadList",
 
         if (active.length)
             this.nodes.total.textContent = _("download.nActive", active.length);
-        else for (let key in values(["total", "percent", "speed", "time"]))
+        else for (let key of values(["total", "percent", "speed", "time"]))
             this.nodes[key].textContent = "";
 
         if (this.shouldSort("complete", "size", "speed", "time"))
@@ -523,7 +529,7 @@ var Downloads_ = Module("downloads", XPCOM(Ci.nsIDownloadProgressListener), {
                 },
 
                 completer: function (context, extra) {
-                    let seen = RealSet(extra.values.map(val => val.substr(1)));
+                    let seen = new RealSet(extra.values.map(val => val.substr(1)));
 
                     context.completions = iter(this.values).filter(([k, v]) => !seen.has(k))
                                                            .map(([k, v]) => [["+" + k, [v, " (", _("sort.ascending"), ")"].join("")],
@@ -534,7 +540,7 @@ var Downloads_ = Module("downloads", XPCOM(Ci.nsIDownloadProgressListener), {
                 has: function () Array.some(arguments, val => this.value.some(v => v.substr(1) == val)),
 
                 validator: function (value) {
-                    let seen = RealSet();
+                    let seen = new RealSet();
                     return value.every(val => /^[+-]/.test(val) && hasOwnProperty(this.values, val.substr(1))
                                                                 && !seen.add(val.substr(1)))
                         && value.length;
diff --git a/common/modules/finder.jsm b/common/modules/finder.jsm
index 2f263ba0..fad4266c 100644
--- a/common/modules/finder.jsm
+++ b/common/modules/finder.jsm
@@ -50,7 +50,7 @@ var RangeFinder = Module("rangefinder", {
     },
 
     cleanup: function cleanup() {
-        for (let doc in util.iterDocuments()) {
+        for (let doc of util.iterDocuments()) {
             let find = overlay.getData(doc, "range-find", null);
             if (find)
                 find.highlight(true);
@@ -436,9 +436,9 @@ var RangeFind = Class("RangeFind", {
         return ranges[0];
     },
 
-    findSubRanges: function findSubRanges(range) {
+    findSubRanges: function* findSubRanges(range) {
         let doc = range.startContainer.ownerDocument;
-        for (let elem in this.elementPath(doc)) {
+        for (let elem of this.elementPath(doc)) {
             let r = RangeFind.nodeRange(elem);
             if (RangeFind.contains(range, r))
                 yield r;
@@ -475,7 +475,7 @@ var RangeFind = Class("RangeFind", {
         else {
             this.selections = [];
             let string = this.lastString;
-            for (let r in this.iter(string)) {
+            for (let r of this.iter(string)) {
                 let controller = this.range.selectionController;
                 for (let node = r.startContainer; node; node = node.parentNode)
                     if (node instanceof Ci.nsIDOMNSEditableElement) {
@@ -495,25 +495,25 @@ var RangeFind = Class("RangeFind", {
         }
     },
 
-    indexIter: function indexIter(private_) {
+    indexIter: function* indexIter(private_) {
         let idx = this.range.index;
         if (this.backward)
             var groups = [util.range(idx + 1, 0, -1), util.range(this.ranges.length, idx, -1)];
         else
             var groups = [util.range(idx, this.ranges.length), util.range(0, idx + 1)];
 
-        for (let i in groups[0])
+        for (let i of groups[0])
             yield i;
 
         if (!private_) {
             this.wrapped = true;
             this.lastRange = null;
-            for (let i in groups[1])
+            for (let i of groups[1])
                 yield i;
         }
     },
 
-    iter: function iter(word) {
+    iter: function* iter(word) {
         let saved = ["lastRange", "lastString", "range", "regexp"].map(s => [s, this[s]]);
         let res;
         try {
@@ -522,8 +522,8 @@ var RangeFind = Class("RangeFind", {
             this.regexp = false;
             if (regexp) {
                 let re = RegExp(word, "gm" + this.flags);
-                for (this.range in array.iterValues(this.ranges)) {
-                    for (let match in util.regexp.iterate(re, DOM.stringify(this.range.range, true))) {
+                for (this.range of array.iterValues(this.ranges)) {
+                    for (let match of util.regexp.iterate(re, DOM.stringify(this.range.range, true))) {
                         let lastRange = this.lastRange;
                         if (res = this.find(null, this.reverse, true))
                             yield res;
@@ -565,7 +565,7 @@ var RangeFind = Class("RangeFind", {
             if (!self.elementPath)
                 push(range);
             else
-                for (let r in self.findSubRanges(range))
+                for (let r of self.findSubRanges(range))
                     push(r);
         }
         function rec(win) {
@@ -575,7 +575,7 @@ var RangeFind = Class("RangeFind", {
             let pageStart = RangeFind.endpoint(pageRange, true);
             let pageEnd = RangeFind.endpoint(pageRange, false);
 
-            for (let frame in array.iterValues(win.frames)) {
+            for (let frame of array.iterValues(win.frames)) {
                 let range = doc.createRange();
                 if (DOM(frame.frameElement).style.visibility == "visible") {
                     range.selectNode(frame.frameElement);
@@ -588,7 +588,7 @@ var RangeFind = Class("RangeFind", {
 
             let anonNodes = doc.getAnonymousNodes(doc.documentElement);
             if (anonNodes) {
-                for (let [, elem] in iter(anonNodes)) {
+                for (let [, elem] of iter(anonNodes)) {
                     let range = RangeFind.nodeContents(elem);
                     pushRange(RangeFind.endpoint(range, true), RangeFind.endpoint(range, false));
                 }
@@ -649,7 +649,7 @@ var RangeFind = Class("RangeFind", {
         if (pattern == "")
             var range = this.startRange;
         else
-            for (let i in this.indexIter(private_)) {
+            for (let i of this.indexIter(private_)) {
                 if (!private_ && this.range.window != this.ranges[i].window && this.range.window != this.ranges[i].window.parent) {
                     this.range.descroll();
                     this.range.deselect();
@@ -706,11 +706,11 @@ var RangeFind = Class("RangeFind", {
     set stale(val) this._stale = val,
 
     addListeners: function addListeners() {
-        for (let range in array.iterValues(this.ranges))
+        for (let range of array.iterValues(this.ranges))
             range.window.addEventListener("unload", this.bound.onUnload, true);
     },
     purgeListeners: function purgeListeners() {
-        for (let range in array.iterValues(this.ranges))
+        for (let range of array.iterValues(this.ranges))
             try {
                 range.window.removeEventListener("unload", this.bound.onUnload, true);
             }
diff --git a/common/modules/help.jsm b/common/modules/help.jsm
index 298309d4..35bab00a 100644
--- a/common/modules/help.jsm
+++ b/common/modules/help.jsm
@@ -28,7 +28,7 @@ var HelpBuilder = Class("HelpBuilder", {
             // Scrape the list of help files from all.xml
             this.tags["all"] = this.tags["all.xml"] = "all";
             let files = this.findHelpFile("all").map(doc =>
-                    [f.value for (f in DOM.XPath("//dactyl:include/@href", doc))]);
+                    [f.value for (f of DOM.XPath("//dactyl:include/@href", doc))]);
 
             // Scrape the tags from the rest of the help files.
             array.flatten(files).forEach(function (file) {
@@ -51,8 +51,8 @@ var HelpBuilder = Class("HelpBuilder", {
 
     // Find the tags in the document.
     addTags: function addTags(file, doc) {
-        for (let elem in DOM.XPath("//@tag|//dactyl:tags/text()|//dactyl:tag/text()", doc))
-                for (let tag in values((elem.value || elem.textContent).split(/\s+/)))
+        for (let elem of DOM.XPath("//@tag|//dactyl:tags/text()|//dactyl:tag/text()", doc))
+                for (let tag of values((elem.value || elem.textContent).split(/\s+/)))
             this.tags[tag] = file;
     },
 
@@ -61,7 +61,7 @@ var HelpBuilder = Class("HelpBuilder", {
     // Find help and overlay files with the given name.
     findHelpFile: function findHelpFile(file) {
         let result = [];
-        for (let base in values(this.bases)) {
+        for (let base of values(this.bases)) {
             let url = [base, file, ".xml"].join("");
             let res = util.httpGet(url, { quiet: true });
             if (res) {
@@ -135,7 +135,7 @@ var Help = Module("Help", {
                 let res = [];
                 let list, space, i = 0;
 
-                for (let match in re.iterate(text)) {
+                for (let match of re.iterate(text)) {
                     if (match.comment)
                         continue;
                     else if (match.char) {
@@ -211,7 +211,7 @@ var Help = Module("Help", {
     flush: function flush(entries, time) {
         cache.flushEntry("help.json", time);
 
-        for (let entry in values(Array.concat(entries || [])))
+        for (let entry of values(Array.concat(entries || [])))
             cache.flushEntry(entry, time);
     },
 
@@ -244,7 +244,7 @@ var Help = Module("Help", {
 
             function format(item) item.description + "#" + encodeURIComponent(item.text);
 
-            for (let [i, item] in Iterator(items)) {
+            for (let item of items) {
                 if (item.text == topic)
                     return format(item);
                 else if (!partialMatch && topic)
@@ -271,7 +271,7 @@ var Help = Module("Help", {
                 if (hasOwnProperty(help.files, helpFile))
                     dactyl.open("dactyl://help/" + helpFile, { from: "help" });
                 else
-                    dactyl.echomsg(_("help.noFile", helpFile.quote()));
+                    dactyl.echomsg(_("help.noFile", JSON.stringify(helpFile)));
                 return;
             }
 
@@ -304,8 +304,8 @@ var Help = Module("Help", {
                     addURIEntry(file, "data:text/plain;charset=UTF-8," + encodeURI(data));
             }
 
-            let empty = RealSet("area base basefont br col frame hr img input isindex link meta param"
-                                .split(" "));
+            let empty = new RealSet("area base basefont br col frame hr img input isindex link meta param"
+                                    .split(" "));
             function fix(node) {
                 switch (node.nodeType) {
                 case Ci.nsIDOMNode.ELEMENT_NODE:
@@ -314,10 +314,10 @@ var Help = Module("Help", {
 
                     data.push("<", node.localName);
                     if (node instanceof Ci.nsIDOMHTMLHtmlElement)
-                        data.push(" xmlns=" + XHTML.quote(),
-                                  " xmlns:dactyl=" + NS.quote());
+                        data.push(" xmlns=" + JSON.stringify(XHTML),
+                                  " xmlns:dactyl=" + JSON.stringify(NS));
 
-                    for (let { name, value } in array.iterValues(node.attributes)) {
+                    for (let { name, value } of array.iterValues(node.attributes)) {
                         if (name == "dactyl:highlight") {
                             styles.add(value);
                             name = "class";
@@ -362,9 +362,9 @@ var Help = Module("Help", {
 
             let { buffer, content, events } = modules;
             let chromeFiles = {};
-            let styles = RealSet();
+            let styles = new RealSet;
 
-            for (let [file, ] in Iterator(help.files)) {
+            for (let [file, ] of iter(help.files)) {
                 let url = "dactyl://help/" + file;
                 dactyl.open(url);
                 util.waitFor(() => (content.location.href == url && buffer.loaded &&
@@ -380,7 +380,8 @@ var Help = Module("Help", {
                 addDataEntry(file + ".xhtml", data.join(""));
             }
 
-            data = [h for (h in highlight) if (styles.has(h.class) || /^Help/.test(h.class))]
+            data = [h for (h of highlight)
+                    if (styles.has(h.class) || /^Help/.test(h.class))]
                 .map(h => h.selector
                            .replace(/^\[.*?=(.*?)\]/, ".hl-$1")
                            .replace(/html\|/g, "") + "\t" + "{" + h.cssText + "}")
@@ -393,7 +394,7 @@ var Help = Module("Help", {
             while ((m = re.exec(data)))
                 chromeFiles[m[0]] = m[2];
 
-            for (let [uri, leaf] in Iterator(chromeFiles))
+            for (let [uri, leaf] of iter(chromeFiles))
                 addURIEntry(leaf, uri);
 
             if (zip)
diff --git a/common/modules/highlight.jsm b/common/modules/highlight.jsm
index ab03dec7..2a73f423 100644
--- a/common/modules/highlight.jsm
+++ b/common/modules/highlight.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -29,7 +29,7 @@ Highlight.liveProperty = function (name, prop) {
         this.set(name, val);
 
         if (name === "value" || name === "extends")
-            for (let h in highlight)
+            for (let h of highlight)
                 if (h.extends.indexOf(this.class) >= 0)
                     h.style.css = h.css;
 
@@ -84,7 +84,8 @@ update(Highlight.prototype, {
     get cssText() this.inheritedCSS + this.value,
 
     toString: function () "Highlight(" + this.class + ")\n\t" +
-        [k + ": " + String(v).quote() for ([k, v] in this)] .join("\n\t")
+        [k + ": " + JSON.stringify(String(v))
+         for ([k, v] of this)].join("\n\t")
 });
 
 /**
@@ -100,7 +101,7 @@ var Highlights = Module("Highlight", {
 
     keys: function keys() Object.keys(this.highlight).sort(),
 
-    __iterator__: function () values(this.highlight).sort((a, b) => String.localeCompare(a.class, b.class))
+    "@@iterator": function () values(this.highlight).sort((a, b) => String.localeCompare(a.class, b.class))
                                                     .iterValues(),
 
     _create: function _create(agent, args) {
@@ -142,7 +143,7 @@ var Highlights = Module("Highlight", {
                 });
 
                 if (obj.class === obj.baseClass)
-                    for (let h in highlight)
+                    for (let h of highlight)
                         if (h.baseClass === obj.class)
                             this[h.class] = true;
                 obj.style.enabled = true;
@@ -189,7 +190,7 @@ var Highlights = Module("Highlight", {
      * reset.
      */
     clear: function clear() {
-        for (let [k, v] in Iterator(this.highlight))
+        for (let [k, v] of iter(this.highlight))
             this.set(k, null, true);
     },
 
@@ -296,7 +297,7 @@ var Highlights = Module("Highlight", {
             if (bang)
                 highlight.style.enabled = true;
        }, this);
-       for (let h in this)
+       for (let h of this)
            h.style.css = h.css;
     }
 }, {
@@ -360,7 +361,7 @@ var Highlights = Module("Highlight", {
                               template.highlightRegexp(h.value, /\b[-\w]+(?=:)|\/\*.*?\*\//g,
                                                        match => ["span", { highlight: match[0] == "/" ? "Comment" : "Key" }, match])
                              ]
-                             for (h in highlight)
+                             for (h of highlight)
                              if (!key || h.class.indexOf(key) > -1))));
                 else if (!key && clear)
                     highlight.clear();
@@ -416,7 +417,7 @@ var Highlights = Module("Highlight", {
                             "-link": v.extends.length ? v.extends : undefined
                         }
                     }
-                    for (v in Iterator(highlight))
+                    for (v of highlight)
                     if (v.value != v.defaultValue)
                 ]
             });
@@ -443,7 +444,7 @@ var Highlights = Module("Highlight", {
 
         completion.highlightGroup = function highlightGroup(context) {
             context.title = ["Highlight Group", "Value"];
-            context.completions = [[v.class, v.value] for (v in highlight)];
+            context.completions = [[v.class, v.value] for (v of highlight)];
         };
     },
     javascript: function initJavascript(dactyl, modules, window) {
diff --git a/common/modules/io.jsm b/common/modules/io.jsm
index c1a28320..6b062500 100644
--- a/common/modules/io.jsm
+++ b/common/modules/io.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2012 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -33,188 +33,191 @@ var IO = Module("io", {
         lazyRequire("config", ["config"], this);
     },
 
-    Local: function Local(dactyl, modules, window) let ({ io, plugins } = modules) ({
+    Local: function Local(dactyl, modules, window) {
+        let { io, plugins } = modules;
+        return {
 
-        init: function init() {
-            this.config = modules.config;
-            this._processDir = services.directory.get("CurWorkD", Ci.nsIFile);
-            this._cwd = this._processDir.path;
-            this._oldcwd = null;
+            init: function init() {
+                this.config = modules.config;
+                this._processDir = services.directory.get("CurWorkD", Ci.nsIFile);
+                this._cwd = this._processDir.path;
+                this._oldcwd = null;
 
-            this._lastRunCommand = ""; // updated whenever the users runs a command with :!
-            this._scriptNames = RealSet();
-        },
-
-        CommandFileMode: Class("CommandFileMode", modules.CommandMode, {
-            init: function init(prompt, params) {
-                init.supercall(this);
-                this.prompt = isArray(prompt) ? prompt : ["Question", prompt];
-                update(this, params);
+                this._lastRunCommand = ""; // updated whenever the users runs a command with :!
+                this._scriptNames = new RealSet;
             },
 
-            historyKey: "file",
+            CommandFileMode: Class("CommandFileMode", modules.CommandMode, {
+                init: function init(prompt, params) {
+                    init.supercall(this);
+                    this.prompt = isArray(prompt) ? prompt : ["Question", prompt];
+                    update(this, params);
+                },
 
-            get mode() modules.modes.FILE_INPUT,
+                historyKey: "file",
 
-            complete: function (context) {
-                if (this.completer)
-                    this.completer(context);
+                get mode() modules.modes.FILE_INPUT,
 
-                context = context.fork("files", 0);
-                modules.completion.file(context);
-                context.filters = context.filters.concat(this.filters || []);
-            }
-        }),
-
-        /**
-         * Returns all directories named *name* in 'runtimepath'.
-         *
-         * @param {string} name
-         * @returns {nsIFile[])
-         */
-        getRuntimeDirectories: function getRuntimeDirectories(name) {
-            return modules.options.get("runtimepath").files
-                .map(dir => dir.child(name))
-                .filter(dir => (dir.exists() && dir.isDirectory() && dir.isReadable()));
-        },
-
-        // FIXME: multiple paths?
-        /**
-         * Sources files found in 'runtimepath'. For each relative path in *paths*
-         * each directory in 'runtimepath' is searched and if a matching file is
-         * found it is sourced. Only the first file found (per specified path) is
-         * sourced unless *all* is specified, then all found files are sourced.
-         *
-         * @param {[string]} paths An array of relative paths to source.
-         * @param {boolean} all Whether all found files should be sourced.
-         */
-        sourceFromRuntimePath: function sourceFromRuntimePath(paths, all) {
-            let dirs = modules.options.get("runtimepath").files;
-            let found = null;
-
-            dactyl.echomsg(_("io.searchingFor", paths.join(" ").quote(), modules.options.get("runtimepath").stringValue), 2);
-
-        outer:
-            for (let dir in values(dirs)) {
-                for (let [, path] in Iterator(paths)) {
-                    let file = dir.child(path);
-
-                    dactyl.echomsg(_("io.searchingFor", file.path.quote()), 3);
-
-                    if (file.exists() && file.isFile() && file.isReadable()) {
-                        found = io.source(file.path, false) || true;
-
-                        if (!all)
-                            break outer;
+                complete: function (context) {
+                    if (this.completer)
+                        this.completer(context);
+
+                    context = context.fork("files", 0);
+                    modules.completion.file(context);
+                    context.filters = context.filters.concat(this.filters || []);
+                }
+            }),
+
+            /**
+             * Returns all directories named *name* in 'runtimepath'.
+             *
+             * @param {string} name
+             * @returns {nsIFile[]
+             */
+            getRuntimeDirectories: function getRuntimeDirectories(name) {
+                return modules.options.get("runtimepath").files
+                    .map(dir => dir.child(name))
+                    .filter(dir => (dir.exists() && dir.isDirectory() && dir.isReadable()));
+            },
+
+            // FIXME: multiple paths?
+            /**
+             * Sources files found in 'runtimepath'. For each relative path in *paths*
+             * each directory in 'runtimepath' is searched and if a matching file is
+             * found it is sourced. Only the first file found (per specified path) is
+             * sourced unless *all* is specified, then all found files are sourced.
+             *
+             * @param {[string]} paths An array of relative paths to source.
+             * @param {boolean} all Whether all found files should be sourced.
+             */
+            sourceFromRuntimePath: function sourceFromRuntimePath(paths, all) {
+                let dirs = modules.options.get("runtimepath").files;
+                let found = null;
+
+                dactyl.echomsg(_("io.searchingFor", JSON.stringify(paths.join(" ")), modules.options.get("runtimepath").stringValue), 2);
+
+            outer:
+                for (let dir of values(dirs)) {
+                    for (let [, path] of iter(paths)) {
+                        let file = dir.child(path);
+
+                        dactyl.echomsg(_("io.searchingFor", JSON.stringify(file.path)), 3);
+
+                        if (file.exists() && file.isFile() && file.isReadable()) {
+                            found = io.source(file.path, false) || true;
+
+                            if (!all)
+                                break outer;
+                        }
                     }
                 }
-            }
 
-            if (!found)
-                dactyl.echomsg(_("io.notInRTP", paths.join(" ").quote()), 1);
-
-            return found;
-        },
-
-        /**
-         * Reads Ex commands, JavaScript or CSS from *filename*.
-         *
-         * @param {string} filename The name of the file to source.
-         * @param {object} params Extra parameters:
-         *      group:  The group in which to execute commands.
-         *      silent: Whether errors should not be reported.
-         */
-        source: function source(filename, params) {
-            const { contexts } = modules;
-            defineModule.loadLog.push("sourcing " + filename);
-
-            if (!isObject(params))
-                params = { silent: params };
-
-            let time = Date.now();
-            return contexts.withContext(null, function () {
-                try {
-                    var file = util.getFile(filename) || io.File(filename);
+                if (!found)
+                    dactyl.echomsg(_("io.notInRTP", JSON.stringify(paths.join(" "))), 1);
 
-                    if (!file.exists() || !file.isReadable() || file.isDirectory()) {
-                        if (!params.silent)
-                            dactyl.echoerr(_("io.notReadable", filename.quote()));
-                        return;
-                    }
+                return found;
+            },
 
-                    dactyl.echomsg(_("io.sourcing", filename.quote()), 2);
+            /**
+             * Reads Ex commands, JavaScript or CSS from *filename*.
+             *
+             * @param {string} filename The name of the file to source.
+             * @param {object} params Extra parameters:
+             *      group:  The group in which to execute commands.
+             *      silent: Whether errors should not be reported.
+             */
+            source: function source(filename, params) {
+                const { contexts } = modules;
+                defineModule.loadLog.push("sourcing " + filename);
+
+                if (!isObject(params))
+                    params = { silent: params };
+
+                let time = Date.now();
+                return contexts.withContext(null, function () {
+                    try {
+                        var file = util.getFile(filename) || io.File(filename);
 
-                    let uri = file.URI;
+                        if (!file.exists() || !file.isReadable() || file.isDirectory()) {
+                            if (!params.silent)
+                                dactyl.echoerr(_("io.notReadable", JSON.stringify(filename)));
+                            return;
+                        }
 
-                    let sourceJSM = function sourceJSM() {
-                        context = contexts.Module(uri);
-                        dactyl.triggerObserver("io.source", context, file, file.lastModifiedTime);
-                    };
+                        dactyl.echomsg(_("io.sourcing", JSON.stringify(filename)), 2);
 
-                    if (/\.jsm$/.test(filename))
-                        sourceJSM();
-                    else if (/\.js$/.test(filename)) {
-                        try {
-                            var context = contexts.Script(file, params.group);
-                            if (this._scriptNames.has(file.path))
-                                util.flushCache();
+                        let uri = file.URI;
 
-                            dactyl.loadScript(uri.spec, context);
+                        let sourceJSM = function sourceJSM() {
+                            context = contexts.Module(uri);
                             dactyl.triggerObserver("io.source", context, file, file.lastModifiedTime);
-                        }
-                        catch (e) {
-                            if (e == Contexts) { // Hack;
-                                context.unload();
-                                sourceJSM();
+                        };
+
+                        if (/\.jsm$/.test(filename))
+                            sourceJSM();
+                        else if (/\.js$/.test(filename)) {
+                            try {
+                                var context = contexts.Script(file, params.group);
+                                if (this._scriptNames.has(file.path))
+                                    util.flushCache();
+
+                                dactyl.loadScript(uri.spec, context);
+                                dactyl.triggerObserver("io.source", context, file, file.lastModifiedTime);
                             }
-                            else {
-                                if (e instanceof Finished)
-                                    return;
-                                if (e.fileName && !(e instanceof FailedAssertion))
-                                    try {
-                                        e.fileName = util.fixURI(e.fileName);
-                                        if (e.fileName == uri.spec)
-                                            e.fileName = filename;
-                                        e.echoerr = [e.fileName, ":", e.lineNumber, ": ", e].join("");
-                                    }
-                                    catch (e) {}
-                                throw e;
+                            catch (e) {
+                                if (e == Contexts) { // Hack;
+                                    context.unload();
+                                    sourceJSM();
+                                }
+                                else {
+                                    if (e instanceof Finished)
+                                        return;
+                                    if (e.fileName && !(e instanceof FailedAssertion))
+                                        try {
+                                            e.fileName = util.fixURI(e.fileName);
+                                            if (e.fileName == uri.spec)
+                                                e.fileName = filename;
+                                            e.echoerr = [e.fileName, ":", e.lineNumber, ": ", e].join("");
+                                        }
+                                        catch (e) {}
+                                    throw e;
+                                }
                             }
                         }
-                    }
-                    else if (/\.css$/.test(filename))
-                        styles.registerSheet(uri.spec, false, true);
-                    else {
-                        context = contexts.Context(file, params.group);
-                        modules.commands.execute(file.read(), null, params.silent,
-                                                 null, {
-                            context: context,
-                            file: file.path,
-                            group: context.GROUP,
-                            line: 1
-                        });
-                        dactyl.triggerObserver("io.source", context, file, file.lastModifiedTime);
-                    }
+                        else if (/\.css$/.test(filename))
+                            styles.registerSheet(uri.spec, false, true);
+                        else {
+                            context = contexts.Context(file, params.group);
+                            modules.commands.execute(file.read(), null, params.silent,
+                                                     null, {
+                                context: context,
+                                file: file.path,
+                                group: context.GROUP,
+                                line: 1
+                            });
+                            dactyl.triggerObserver("io.source", context, file, file.lastModifiedTime);
+                        }
 
-                    this._scriptNames.add(file.path);
+                        this._scriptNames.add(file.path);
 
-                    dactyl.echomsg(_("io.sourcingEnd", filename.quote()), 2);
-                    dactyl.log(_("dactyl.sourced", filename), 3);
+                        dactyl.echomsg(_("io.sourcingEnd", JSON.stringify(filename)), 2);
+                        dactyl.log(_("dactyl.sourced", filename), 3);
 
-                    return context;
-                }
-                catch (e) {
-                    util.reportError(e);
-                    let message = _("io.sourcingError", e.echoerr || (file ? file.path : filename) + ": " + e);
-                    if (!params.silent)
-                        dactyl.echoerr(message);
-                }
-                finally {
-                    defineModule.loadLog.push("done sourcing " + filename + ": " + (Date.now() - time) + "ms");
-                }
-            }, this);
-        }
-    }),
+                        return context;
+                    }
+                    catch (e) {
+                        util.reportError(e);
+                        let message = _("io.sourcingError", e.echoerr || (file ? file.path : filename) + ": " + e);
+                        if (!params.silent)
+                            dactyl.echoerr(message);
+                    }
+                    finally {
+                        defineModule.loadLog.push("done sourcing " + filename + ": " + (Date.now() - time) + "ms");
+                    }
+                }, this);
+            }
+        };
+    },
 
     charsets: Class.Memoize(function () {
         const BASE = "@mozilla.org/intl/unicode/decoder;1?charset=";
@@ -277,7 +280,7 @@ var IO = Module("io", {
         }
         else {
             let dir = io.File(newDir);
-            util.assert(dir.exists() && dir.isDirectory(), _("io.noSuchDir", dir.path.quote()));
+            util.assert(dir.exists() && dir.isDirectory(), _("io.noSuchDir", JSON.stringify(dir.path)));
             dir.normalize();
             [this._cwd, this._oldcwd] = [dir.path, this.cwd];
         }
@@ -288,11 +291,13 @@ var IO = Module("io", {
      * @property {function} File class.
      * @final
      */
-    File: Class.Memoize(function () let (io = this)
-        Class("File", File, {
+    File: Class.Memoize(function () {
+        let io = this;
+        return Class("File", File, {
             init: function init(path, checkCWD=true)
                 init.supercall(this, path, checkCWD && io.cwd)
-        })),
+        });
+    }),
 
     /**
      * @property {Object} The current file sourcing context. As a file is
@@ -380,7 +385,7 @@ var IO = Module("io", {
      * @param {nsIURI|string} file The URI of the JAR file to list.
      * @param {string} path The prefix path to search.
      */
-    listJar: function listJar(file, path) {
+    listJar: function* listJar(file, path) {
         file = util.getFile(file);
         if (file && file.exists() && file.isFile() && file.isReadable()) {
             // let jar = services.zipReader.getZip(file); Crashes.
@@ -389,7 +394,7 @@ var IO = Module("io", {
                 let filter = RegExp("^" + util.regexp.escape(decodeURI(path))
                                     + "[^/]*/?$");
 
-                for (let entry in iter(jar.findEntries("*")))
+                for (let entry of iter(jar.findEntries("*")))
                     if (filter.test(entry))
                         yield entry;
             }
@@ -426,7 +431,7 @@ var IO = Module("io", {
         if (config.OS.isWindows)
             dirs = [io.cwd].concat(dirs);
 
-        for (let [, dir] in Iterator(dirs))
+        for (let dir of dirs)
             try {
                 dir = this.File(dir, true);
 
@@ -438,7 +443,7 @@ var IO = Module("io", {
                 // automatically try to add the executable path extensions on windows
                 if (config.OS.isWindows) {
                     let extensions = services.environment.get("PATHEXT").split(";");
-                    for (let [, extension] in Iterator(extensions)) {
+                    for (let extension of extensions) {
                         file = dir.child(bin + extension);
                         if (file.exists())
                             return file;
@@ -494,8 +499,6 @@ var IO = Module("io", {
         return deferred.promise;
     },
 
-    // TODO: when https://bugzilla.mozilla.org/show_bug.cgi?id=68702 is
-    // fixed use that instead of a tmpfile
     /**
      * Runs *command* in a subshell and returns the output. The shell used is
      * that specified by the 'shell' option.
@@ -624,7 +627,7 @@ var IO = Module("io", {
                 }
                 else {
                     let dirs = modules.options.get("cdpath").files;
-                    for (let dir in values(dirs)) {
+                    for (let dir of values(dirs)) {
                         dir = dir.child(arg);
 
                         if (dir.exists() && dir.isDirectory() && dir.isReadable()) {
@@ -634,7 +637,7 @@ var IO = Module("io", {
                         }
                     }
 
-                    dactyl.echoerr(_("io.noSuchDir", arg.quote()));
+                    dactyl.echoerr(_("io.noSuchDir", JSON.stringify(arg)));
                     dactyl.echoerr(_("io.commandFailed"));
                 }
             }, {
@@ -655,10 +658,13 @@ var IO = Module("io", {
 
                 let file = io.File(args[0] || io.getRCFile(null, true));
 
-                dactyl.assert(!file.exists() || args.bang, _("io.exists", file.path.quote()));
+                dactyl.assert(!file.exists() || args.bang, _("io.exists", JSON.stringify(file.path)));
 
                 // TODO: Use a set/specifiable list here:
-                let lines = [cmd.serialize().map(commands.commandToString, cmd) for (cmd in commands.iterator()) if (cmd.serialize)];
+                let lines = [cmd.serialize().map(commands.commandToString, cmd)
+                             for (cmd of commands.iterator())
+                             if (cmd.serialize)];
+
                 lines = array.flatten(lines);
 
                 lines.unshift('"' + config.version + "\n");
@@ -666,10 +672,10 @@ var IO = Module("io", {
 
                 try {
                     file.write(lines.join("\n").concat("\n"));
-                    dactyl.echomsg(_("io.writing", file.path.quote()), 2);
+                    dactyl.echomsg(_("io.writing", JSON.stringify(file.path)), 2);
                 }
                 catch (e) {
-                    dactyl.echoerr(_("io.notWriteable", file.path.quote()));
+                    dactyl.echoerr(_("io.notWriteable", JSON.stringify(file.path)));
                     dactyl.log(_("error.notWriteable", file.path, e.message)); // XXX
                 }
             }, {
@@ -685,19 +691,19 @@ var IO = Module("io", {
 
                 if (args.length) {
                     var rtDir = io.File(args[0]);
-                    dactyl.assert(rtDir.exists(), _("io.noSuchDir", rtDir.path.quote()));
+                    dactyl.assert(rtDir.exists(), _("io.noSuchDir", JSON.stringify(rtDir.path)));
                 }
                 else
                     rtDir = io.File(config.OS.isWindows ? "~/vimfiles/" : "~/.vim/");
 
-                dactyl.assert(!rtDir.exists() || rtDir.isDirectory(), _("io.eNotDir", rtDir.path.quote()));
+                dactyl.assert(!rtDir.exists() || rtDir.isDirectory(), _("io.eNotDir", JSON.stringify(rtDir.path)));
 
                 let rtItems = { ftdetect: {}, ftplugin: {}, syntax: {} };
 
                 // require bang if any of the paths exist
-                for (let [type, item] in iter(rtItems)) {
+                for (let [type, item] of iter(rtItems)) {
                     let file = io.File(rtDir).child(type, config.name + ".vim");
-                    dactyl.assert(!file.exists() || args.bang, _("io.exists", file.path.quote()));
+                    dactyl.assert(!file.exists() || args.bang, _("io.exists", JSON.stringify(file.path)));
                     item.file = file;
                 }
 
@@ -825,7 +831,7 @@ unlet s:cpo_save
                     let lines = [];
                     lines.__defineGetter__("last", function () this[this.length - 1]);
 
-                    for (let item in values(items.array || items)) {
+                    for (let item of values(items.array || items)) {
                         if (item.length > width && (!lines.length || lines.last.length > 1)) {
                             lines.push([prefix]);
                             width = WIDTH - prefix.length;
@@ -851,22 +857,22 @@ unlet s:cpo_save
                     autocommands: wrap("syn keyword " + config.name + "AutoEvent ",
                                        keys(config.autocommands)),
                     commands: wrap("syn keyword " + config.name + "Command ",
-                                  array(c.specs for (c in commands.iterator())).flatten()),
+                                  array(c.specs for (c of commands.iterator())).flatten()),
                     options: wrap("syn keyword " + config.name + "Option ",
-                                  array(o.names for (o in options) if (o.type != "boolean")).flatten()),
+                                  array(o.names for (o of options) if (o.type != "boolean")).flatten()),
                     toggleoptions: wrap("let s:toggleOptions = [",
-                                        array(o.realNames for (o in options) if (o.type == "boolean"))
+                                        array(o.realNames for (o of options) if (o.type == "boolean"))
                                             .flatten().map(String.quote),
                                         ", ") + "]"
                 }; //}}}
 
-                for (let { file, template } in values(rtItems)) {
+                for (let { file, template } of values(rtItems)) {
                     try {
                         file.write(util.compileMacro(template, true)(params));
-                        dactyl.echomsg(_("io.writing", file.path.quote()), 2);
+                        dactyl.echomsg(_("io.writing", JSON.stringify(file.path)), 2);
                     }
                     catch (e) {
-                        dactyl.echoerr(_("io.notWriteable", file.path.quote()));
+                        dactyl.echoerr(_("io.notWriteable", JSON.stringify(file.path)));
                         dactyl.log(_("error.notWriteable", file.path, e.message));
                     }
                 }
@@ -896,7 +902,7 @@ unlet s:cpo_save
                 else
                     modules.commandline.commandOutput(
                         template.tabular(["<SNR>", "Filename"], ["text-align: right; padding-right: 1em;"],
-                            ([i + 1, file] for ([i, file] in Iterator(names)))));
+                            ([i + 1, file] for ([i, file] of iter(names)))));
 
             },
             { argCount: "0" });
@@ -1022,7 +1028,7 @@ unlet s:cpo_save
                               isDirectory: function () s.substr(-1) == "/",
                               leafName: /([^\/]*)\/?$/.exec(s)[1]
                         }
-                        for (s in io.listJar(uri.JARFile, getDir(uri.JAREntry)))]
+                        for (s of io.listJar(uri.JARFile, getDir(uri.JAREntry)))]
                 };
             else
                 context.generate = function generate_file() {
@@ -1035,7 +1041,7 @@ unlet s:cpo_save
         };
 
         completion.runtime = function (context) {
-            for (let [, dir] in Iterator(modules.options["runtimepath"]))
+            for (let dir of modules.options["runtimepath"])
                 context.fork(dir, 0, this, function (context) {
                     dir = dir.replace("/+$", "") + "/";
                     completion.file(context, true, dir + context.filter);
@@ -1050,10 +1056,10 @@ unlet s:cpo_save
                 let dirNames = services.environment.get("PATH").split(config.OS.pathListSep);
                 let commands = [];
 
-                for (let [, dirName] in Iterator(dirNames)) {
+                for (let dirName of dirNames) {
                     let dir = io.File(dirName);
                     if (dir.exists() && dir.isDirectory())
-                        commands.push([[file.leafName, dir.path] for (file in iter(dir.directoryEntries))
+                        commands.push([[file.leafName, dir.path] for (file of iter(dir.directoryEntries))
                                        if (file.isFile() && file.isExecutable())]);
                 }
 
diff --git a/common/modules/javascript.jsm b/common/modules/javascript.jsm
index 8b23315d..de163acf 100644
--- a/common/modules/javascript.jsm
+++ b/common/modules/javascript.jsm
@@ -69,24 +69,24 @@ var JavaScript = Module("javascript", {
         return undefined;
     },
 
-    iter: function iter_(obj, toplevel) {
+    iter: function* iter_(obj, toplevel) {
         if (obj == null)
             return;
 
-        let seen = RealSet(isinstance(obj, ["Sandbox"]) ? JavaScript.magicalNames : []);
+        let seen = new RealSet(isinstance(obj, ["Sandbox"]) ? JavaScript.magicalNames : []);
         let globals = values(toplevel && this.window === obj ? this.globalNames : []);
 
         if (toplevel && isObject(obj) && "wrappedJSObject" in obj)
             if (!seen.add("wrappedJSObject"))
                 yield "wrappedJSObject";
 
-        for (let key in iter(globals, properties(obj, !toplevel)))
+        for (let key of iter(globals, properties(obj, !toplevel)))
             if (!seen.add(key))
                 yield key;
 
         // Properties aren't visible in an XPCNativeWrapper until
         // they're accessed.
-        for (let key in properties(this.getKey(obj, "wrappedJSObject"),
+        for (let key of properties(this.getKey(obj, "wrappedJSObject"),
                                    !toplevel))
             try {
                 if (key in obj && !seen.has(key))
@@ -104,9 +104,9 @@ var JavaScript = Module("javascript", {
         if (isPrototypeOf.call(this.toplevel, obj) && !toplevel)
             return [];
 
-        let completions = [k for (k in this.iter(obj, toplevel))];
+        let completions = [k for (k of this.iter(obj, toplevel))];
         if (obj === this.modules) // Hack.
-            completions = array.uniq(completions.concat([k for (k in this.iter(this.modules.jsmodules, toplevel))]));
+            completions = array.uniq(completions.concat([k for (k of this.iter(this.modules.jsmodules, toplevel))]));
         return completions;
     },
 
@@ -294,7 +294,7 @@ var JavaScript = Module("javascript", {
         let prev = statement;
         let obj = this.window;
         let cacheKey;
-        for (let [, dot] in Iterator(this._get(frame).dots.concat(stop))) {
+        for (let dot of this._get(frame).dots.concat(stop)) {
             if (dot < statement)
                 continue;
             if (dot > stop || dot <= prev)
@@ -308,7 +308,7 @@ var JavaScript = Module("javascript", {
             if (this._checkFunction(prev, dot, cacheKey))
                 return [];
             if (prev != statement && obj == null) {
-                this.context.message = /*L*/"Error: " + cacheKey.quote() + " is " + String(obj);
+                this.context.message = /*L*/"Error: " + JSON.stringify(cacheKey) + " is " + String(obj);
                 return [];
             }
 
@@ -471,7 +471,7 @@ var JavaScript = Module("javascript", {
         // This allows for things like:
         //   let doc = content.document; let elem = doc.createEle<Tab> ...
         let prev = 0;
-        for (let [, v] in Iterator(this._get(0).fullStatements)) {
+        for (let v of this._get(0).fullStatements) {
             let key = this._str.substring(prev, v + 1);
             if (this._checkFunction(prev, v, key))
                 return null;
@@ -560,7 +560,7 @@ var JavaScript = Module("javascript", {
                 // Split up the arguments
                 let prev = this._get(-2).offset;
                 let args = [];
-                for (let [i, idx] in Iterator(this._get(-2).comma)) {
+                for (let [i, idx] of iter(this._get(-2).comma)) {
                     let arg = this._str.substring(prev + 1, idx);
                     prev = idx;
                     memoize(args, i, () => self.evalled(arg));
@@ -622,26 +622,28 @@ var JavaScript = Module("javascript", {
      * A list of properties of the global object which are not
      * enumerable by any standard method.
      */
-    globalNames: Class.Memoize(function () let (self = this) array.uniq([
-        "Array", "ArrayBuffer", "AttributeName", "Audio", "Boolean", "Components",
-        "CSSFontFaceStyleDecl", "CSSGroupRuleRuleList", "CSSNameSpaceRule",
-        "CSSRGBColor", "CSSRect", "ComputedCSSStyleDeclaration", "Date", "Error",
-        "EvalError", "File", "Float32Array", "Float64Array", "Function",
-        "HTMLDelElement", "HTMLInsElement", "HTMLSpanElement", "Infinity",
-        "InnerModalContentWindow", "InnerWindow", "Int16Array", "Int32Array",
-        "Int8Array", "InternalError", "Iterator", "JSON", "KeyboardEvent",
-        "Math", "NaN", "Namespace", "Number", "Object", "Proxy", "QName",
-        "ROCSSPrimitiveValue", "RangeError", "ReferenceError", "RegExp",
-        "StopIteration", "String", "SyntaxError", "TypeError", "URIError",
-        "Uint16Array", "Uint32Array", "Uint8Array", "XML", "XMLHttpProgressEvent",
-        "XMLList", "XMLSerializer", "XPCNativeWrapper",
-        "XULControllers", "constructor", "decodeURI", "decodeURIComponent",
-        "encodeURI", "encodeURIComponent", "escape", "eval", "isFinite", "isNaN",
-        "isXMLName", "parseFloat", "parseInt", "undefined", "unescape", "uneval"
-    ].concat([k.substr(6) for (k in keys(Ci)) if (/^nsIDOM/.test(k))])
-     .concat([k.substr(3) for (k in keys(Ci)) if (/^nsI/.test(k))])
-     .concat(this.magicalNames)
-     .filter(k => k in self.window))),
+    globalNames: Class.Memoize(function () {
+        return array.uniq([
+            "Array", "ArrayBuffer", "AttributeName", "Audio", "Boolean", "Components",
+            "CSSFontFaceStyleDecl", "CSSGroupRuleRuleList", "CSSNameSpaceRule",
+            "CSSRGBColor", "CSSRect", "ComputedCSSStyleDeclaration", "Date", "Error",
+            "EvalError", "File", "Float32Array", "Float64Array", "Function",
+            "HTMLDelElement", "HTMLInsElement", "HTMLSpanElement", "Infinity",
+            "InnerModalContentWindow", "InnerWindow", "Int16Array", "Int32Array",
+            "Int8Array", "InternalError", "Iterator", "JSON", "KeyboardEvent",
+            "Math", "NaN", "Namespace", "Number", "Object", "Proxy", "QName",
+            "ROCSSPrimitiveValue", "RangeError", "ReferenceError", "RegExp",
+            "StopIteration", "String", "SyntaxError", "TypeError", "URIError",
+            "Uint16Array", "Uint32Array", "Uint8Array", "XML", "XMLHttpProgressEvent",
+            "XMLList", "XMLSerializer", "XPCNativeWrapper",
+            "XULControllers", "constructor", "decodeURI", "decodeURIComponent",
+            "encodeURI", "encodeURIComponent", "escape", "eval", "isFinite", "isNaN",
+            "isXMLName", "parseFloat", "parseInt", "undefined", "unescape", "uneval"
+        ].concat([k.substr(6) for (k of keys(Ci)) if (/^nsIDOM/.test(k))])
+         .concat([k.substr(3) for (k of keys(Ci)) if (/^nsI/.test(k))])
+         .concat(this.magicalNames)
+         .filter(k => k in this.window));
+    }),
 
 }, {
     EVAL_TMP: "__dactyl_eval_tmp",
@@ -675,7 +677,7 @@ var JavaScript = Module("javascript", {
      */
     setCompleter: function (funcs, completers) {
         funcs = Array.concat(funcs);
-        for (let [, func] in Iterator(funcs)) {
+        for (let func of funcs) {
             func.dactylCompleter = function (context, func, obj, args) {
                 let completer = completers[args.length - 1];
                 if (!completer)
diff --git a/common/modules/main.jsm b/common/modules/main.jsm
index c58789f9..e5dade2b 100644
--- a/common/modules/main.jsm
+++ b/common/modules/main.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2009-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2009-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -136,6 +136,8 @@ var Modules = function Modules(window) {
     const create = bind("create", jsmodules.Object);
 
     const modules = update(create(jsmodules), {
+        Symbol: Symbol,
+
         yes_i_know_i_should_not_report_errors_in_these_branches_thanks: [],
 
         jsmodules: jsmodules,
@@ -143,7 +145,7 @@ var Modules = function Modules(window) {
         Module: Module,
 
         load: function load(script) {
-            for (let [i, base] in Iterator(BASES)) {
+            for (let base of BASES) {
                 try {
                     JSMLoader.loadSubScript(base + script + ".js", modules, "UTF-8");
                     return;
@@ -212,8 +214,8 @@ overlay.overlayWindow(Object.keys(config.overlays),
 
         this.startTime = Date.now();
         this.deferredInit = { load: {} };
-        this.seen = RealSet();
-        this.loaded = RealSet();
+        this.seen = new RealSet;
+        this.loaded = new RealSet;
         modules.loaded = this.loaded;
 
         this.modules = modules;
@@ -286,7 +288,7 @@ overlay.overlayWindow(Object.keys(config.overlays),
             if (seen.add(module.className))
                 throw Error("Module dependency loop.");
 
-            for (let dep in values(module.requires))
+            for (let dep of values(module.requires))
                 this.loadModule(Module.constructors[dep], module.className);
 
             defineModule.loadLog.push(
@@ -346,7 +348,7 @@ overlay.overlayWindow(Object.keys(config.overlays),
         let { Module, modules } = this.modules;
 
         defineModule.modules.forEach((mod) => {
-            let names = RealSet(Object.keys(mod.INIT));
+            let names = new RealSet(Object.keys(mod.INIT));
             if ("init" in mod.INIT)
                 names.add("init");
 
@@ -368,7 +370,7 @@ overlay.overlayWindow(Object.keys(config.overlays),
     },
 
     initDependencies: function initDependencies(name, parents) {
-        for (let [k, v] in Iterator(this.deferredInit[name] || {}))
+        for (let [k, v] of iter(this.deferredInit[name] || {}))
             if (!parents || ~parents.indexOf(k))
                 util.trapErrors(v);
     }
diff --git a/common/modules/messages.jsm b/common/modules/messages.jsm
index 82c0f3c6..1cbf3be3 100644
--- a/common/modules/messages.jsm
+++ b/common/modules/messages.jsm
@@ -55,16 +55,16 @@ var Messages = Module("messages", {
                  }
              })),
 
-    iterate: function () {
-        let seen = RealSet();
-        for (let bundle in values(this.bundles))
-            for (let { key, value } in iter(bundle.getSimpleEnumeration(), Ci.nsIPropertyElement))
+    iterate: function* () {
+        let seen = new RealSet;
+        for (let bundle of this.bundles)
+            for (let { key, value } of iter(bundle.getSimpleEnumeration(), Ci.nsIPropertyElement))
                 if (!seen.add(key))
                     yield [key, value];
     },
 
     get: function get(value, default_) {
-        for (let bundle in values(this.bundles))
+        for (let bundle of this.bundles)
             try {
                 let res = bundle.GetStringFromName(value);
                 if (res.slice(0, 2) == "+ ")
@@ -80,7 +80,7 @@ var Messages = Module("messages", {
     },
 
     format: function format(value, args, default_) {
-        for (let bundle in values(this.bundles))
+        for (let bundle of this.bundles)
             try {
                 let res = bundle.formatStringFromName(value, args, args.length);
                 if (res.slice(0, 2) == "+ ")
@@ -105,18 +105,22 @@ var Messages = Module("messages", {
         let { Buffer, commands, hints, io, mappings, modes, options, sanitizer } = overlay.activeModules;
         file = io.File(file);
 
-        function properties(base, iter_, prop="description") iter(function _properties() {
+        function properties(base, iter_, prop="description") iter(function* _properties() {
             function key(...args) [base, obj.identifier || obj.name].concat(args).join(".").replace(/[\\:=]/g, "\\$&");
 
-            for (var obj in iter_) {
+            for (var obj of iter_) {
                 if (!obj.hive || obj.hive.name !== "user") {
                     yield key(prop) + " = " + obj[prop];
 
-                    if (iter_.values)
-                        for (let [k, v] in isArray(obj.values) ? array.iterValues(obj.values) : iter(obj.values))
+                    if (iter_.values) {
+                        let iter_ = isArray(obj.values) ? array.iterValues(obj.values)
+                                                        : iter(obj.values);
+
+                        for (let [k, v] of iter_)
                             yield key("values", k) + " = " + v;
+                    }
 
-                    for (let opt in values(obj.options))
+                    for (let opt of values(obj.options))
                         yield key("options", opt.names[0]) + " = " + opt.description;
 
                     if (obj.deprecated)
@@ -148,7 +152,7 @@ var Messages = Module("messages", {
                 */
 
                 if (!hasOwnProperty(obj, "localizedProperties"))
-                    obj.localizedProperties = RealSet(obj.localizedProperties);
+                    obj.localizedProperties = new RealSet(obj.localizedProperties);
                 obj.localizedProperties.add(prop);
 
                 obj[_prop] = this.default;
diff --git a/common/modules/options.jsm b/common/modules/options.jsm
index 302a1d34..32b32497 100644
--- a/common/modules/options.jsm
+++ b/common/modules/options.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 by Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 by Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -65,7 +65,7 @@ var Option = Class("Option", {
             this.globalValue = this.defaultValue;
     },
 
-    magicalProperties: RealSet(["cleanupValue"]),
+    magicalProperties: new RealSet(["cleanupValue"]),
 
     /**
      * @property {string} This option's description, as shown in :listoptions.
@@ -489,7 +489,7 @@ var Option = Class("Option", {
         get charlist() this.stringlist,
 
         regexplist: function regexplist(k, default_=null) {
-            for (let re in values(this.value))
+            for (let re of values(this.value))
                 if ((re.test || re).call(re, k))
                     return re.result;
             return default_;
@@ -509,7 +509,7 @@ var Option = Class("Option", {
 
         stringlist:  function (vals) vals.map(Option.quote).join(","),
 
-        stringmap:   function (vals) [Option.quote(k, /:/) + ":" + Option.quote(v, /:/) for ([k, v] in Iterator(vals))].join(","),
+        stringmap:   function (vals) [Option.quote(k, /:/) + ":" + Option.quote(v, /:/) for ([k, v] of iter(vals))].join(","),
 
         regexplist:  function (vals) vals.join(","),
         get regexpmap() this.regexplist,
@@ -518,8 +518,12 @@ var Option = Class("Option", {
     },
 
     parse: {
-        number:     function (value) let (val = Option.dequote(value))
-                            Option.validIf(Number(val) % 1 == 0, _("option.intRequired")) && parseInt(val),
+        number:     function (value) {
+            let val = Option.dequote(value);
+            return (Option.validIf(Number(val) % 1 == 0,
+                                  _("option.intRequired")) &&
+                    parseInt(val));
+        },
 
         boolean:    function boolean(value) Option.dequote(value) == "true" || value == true ? true : false,
 
@@ -549,8 +553,10 @@ var Option = Class("Option", {
 
         sitemap: function sitemap(value) Option.parse.list.call(this, value, Option.parseSite),
 
-        list: function list(value, parse) let (prev = null)
-            array.compact(Option.splitList(value, true).map(function (v) {
+        list: function list(value, parse) {
+            let prev = null;
+            return array.compact(Option.splitList(value, true)
+                                       .map(function (v) {
                 let [count, filter, quote] = Commands.parseArg(v, /:/, true);
 
                 let val = v.substr(count + 1);
@@ -563,7 +569,8 @@ var Option = Class("Option", {
                     util.assert(prev, _("error.syntaxError"), false);
                     prev.result += "," + v;
                 }
-            }, this))
+            }, this));
+        },
     },
 
     parseKey: {
@@ -662,13 +669,13 @@ var Option = Class("Option", {
             case "^":
                 return update(res, values);
             case "-":
-                for (let [k, v] in Iterator(values))
+                for (let [k, v] of iter(values))
                     if (v === res[k])
                         delete res[k];
                 return res;
             case "=":
                 if (invert) {
-                    for (let [k, v] in Iterator(values))
+                    for (let [k, v] of iter(values))
                         if (v === res[k])
                             delete res[k];
                         else
@@ -684,7 +691,7 @@ var Option = Class("Option", {
             values = Array.concat(values);
 
             function uniq(ary) {
-                let seen = RealSet();
+                let seen = new RealSet;
                 return ary.filter(elem => !seen.add(elem));
             }
 
@@ -695,11 +702,11 @@ var Option = Class("Option", {
                 // NOTE: Vim doesn't prepend if there's a match in the current value
                 return uniq(Array.concat(values, this.value), true);
             case "-":
-                return this.value.filter(function (item) !this.has(item), RealSet(values));
+                return this.value.filter(function (item) !this.has(item), new RealSet(values));
             case "=":
                 if (invert) {
-                    let keepValues = this.value.filter(function (item) !this.has(item), RealSet(values));
-                    let addValues  = values.filter(function (item) !this.has(item), RealSet(this.value));
+                    let keepValues = this.value.filter(function (item) !this.has(item), new RealSet(values));
+                    let addValues  = values.filter(function (item) !this.has(item), new RealSet(this.value));
                     return addValues.concat(keepValues);
                 }
                 return values;
@@ -747,10 +754,10 @@ var Option = Class("Option", {
             acceptable = completions.call(this);
 
         if (isArray(acceptable))
-            acceptable = RealSet(acceptable.map(([k]) => k));
+            acceptable = new RealSet(acceptable.map(([k]) => k));
         else
-            acceptable = RealSet(this.parseKey(k)
-                                 for (k of Object.keys(acceptable)));
+            acceptable = new RealSet(this.parseKey(k)
+                                     for (k of Object.keys(acceptable)));
 
         if (this.type === "regexpmap" || this.type === "sitemap")
             return Array.concat(vals).every(re => acceptable.has(re.result));
@@ -803,7 +810,7 @@ var Option = Class("Option", {
 
 update(BooleanOption.prototype, {
     names: Class.Memoize(function ()
-                array.flatten([[name, "no" + name] for (name in values(this.realNames))]))
+                array.flatten([[name, "no" + name] for (name of values(this.realNames))]))
 });
 
 var OptionHive = Class("OptionHive", Contexts.Hive, {
@@ -822,157 +829,160 @@ var OptionHive = Class("OptionHive", Contexts.Hive, {
  * @instance options
  */
 var Options = Module("options", {
-    Local: function Local(dactyl, modules, window) let ({ contexts } = modules) ({
-        init: function init() {
-            const self = this;
-
-            update(this, {
-                hives: contexts.Hives("options", Class("OptionHive", OptionHive, { modules: modules })),
-                user: contexts.hives.options.user
-            });
-
-            this.needInit = [];
-            this._options = [];
-            this._optionMap = {};
-
-            storage.newMap("options", { store: false });
-            storage.addObserver("options", function optionObserver(key, event, option) {
-                // Trigger any setters.
-                let opt = self.get(option);
-                if (event == "change" && opt)
-                    opt.set(opt.globalValue, Option.SCOPE_GLOBAL, true);
-            }, window);
-
-            modules.cache.register("options.dtd",
-                () => util.makeDTD(
-                        iter(([["option", o.name, "default"].join("."),
-                               o.type === "string" ? o.defaultValue.replace(/'/g, "''") :
-                               o.defaultValue === true  ? "on"  :
-                               o.defaultValue === false ? "off" : o.stringDefaultValue]
-                              for (o in self)),
-
-                             ([["option", o.name, "type"].join("."), o.type] for (o in self)),
-
-                             config.dtd)),
-                true);
-        },
-
-        signals: {
-            "io.source": function ioSource(context, file, modTime) {
-                cache.flushEntry("options.dtd", modTime);
-            }
-        },
+    Local: function Local(dactyl, modules, window) {
+        let { contexts } = modules;
+        return {
+            init: function init() {
+                const self = this;
+
+                update(this, {
+                    hives: contexts.Hives("options", Class("OptionHive", OptionHive, { modules: modules })),
+                    user: contexts.hives.options.user
+                });
 
-        dactyl: dactyl,
+                this.needInit = [];
+                this._options = [];
+                this._optionMap = {};
+
+                storage.newMap("options", { store: false });
+                storage.addObserver("options", function optionObserver(key, event, option) {
+                    // Trigger any setters.
+                    let opt = self.get(option);
+                    if (event == "change" && opt)
+                        opt.set(opt.globalValue, Option.SCOPE_GLOBAL, true);
+                }, window);
+
+                modules.cache.register("options.dtd",
+                    () => util.makeDTD(
+                            iter(([["option", o.name, "default"].join("."),
+                                   o.type === "string" ? o.defaultValue.replace(/'/g, "''") :
+                                   o.defaultValue === true  ? "on"  :
+                                   o.defaultValue === false ? "off" : o.stringDefaultValue]
+                                  for (o of self)),
+
+                                 ([["option", o.name, "type"].join("."), o.type] for (o in self)),
+
+                                 config.dtd)),
+                    true);
+            },
 
-        /**
-         * Lists all options in *scope* or only those with changed values if
-         * *onlyNonDefault* is specified.
-         *
-         * @param {function(Option)} filter Limit the list
-         * @param {number} scope Only list options in this scope (see
-         *     {@link Option#scope}).
-         */
-        list: function list(filter, scope) {
-            if (!scope)
-                scope = Option.SCOPE_BOTH;
-
-            function opts(opt) {
-                for (let opt in Iterator(this)) {
-                    if (filter && !filter(opt))
-                        continue;
-                    if (!(opt.scope & scope))
-                        continue;
-
-                    let option = {
-                        __proto__: opt,
-                        isDefault: opt.isDefault,
-                        default:   opt.stringDefaultValue,
-                        pre:       "\u00a0\u00a0", // Unicode nonbreaking space.
-                        value:     []
-                    };
-
-                    if (opt.type == "boolean") {
-                        if (!opt.value)
-                            option.pre = "no";
-                        option.default = (opt.defaultValue ? "" : "no") + opt.name;
-                    }
-                    else if (isArray(opt.value) && opt.type != "charlist")
-                        option.value = ["", "=",
-                                        template.map(opt.value,
-                                                     v => template.highlight(String(v)),
-                                                     ["", ",",
-                                                      ["span", { style: "width: 0; display: inline-block" }, " "]])];
-                    else
-                        option.value = ["", "=", template.highlight(opt.stringValue)];
-                    yield option;
+            signals: {
+                "io.source": function ioSource(context, file, modTime) {
+                    cache.flushEntry("options.dtd", modTime);
                 }
-            };
-
-            modules.commandline.commandOutput(
-                template.options("Options", opts.call(this), this["verbose"] > 0));
-        },
-
-        cleanup: function cleanup() {
-            for (let opt in this)
-                if (opt.cleanupValue != null)
-                    opt.stringValue = opt.cleanupValue;
-        },
-
-        /**
-         * Adds a new option.
-         *
-         * @param {[string]} names All names for the option.
-         * @param {string} description A description of the option.
-         * @param {string} type The option type (see {@link Option#type}).
-         * @param {value} defaultValue The option's default value.
-         * @param {Object} extra An optional extra configuration hash (see
-         *     {@link Map#extraInfo}).
-         * @optional
-         */
-        add: function add(names, description, type, defaultValue, extraInfo) {
-            if (!util.isDactyl(Components.stack.caller))
-                deprecated.warn(add, "options.add", "group.options.add");
+            },
 
-            util.assert(type in Option.types, _("option.noSuchType", type),
-                        false);
+            dactyl: dactyl,
+
+            /**
+             * Lists all options in *scope* or only those with changed values if
+             * *onlyNonDefault* is specified.
+             *
+             * @param {function(Option)} filter Limit the list
+             * @param {number} scope Only list options in this scope (see
+             *     {@link Option#scope}).
+             */
+            list: function list(filter, scope) {
+                if (!scope)
+                    scope = Option.SCOPE_BOTH;
+
+                function* opts(opt) {
+                    for (let opt of this) {
+                        if (filter && !filter(opt))
+                            continue;
+                        if (!(opt.scope & scope))
+                            continue;
+
+                        let option = {
+                            __proto__: opt,
+                            isDefault: opt.isDefault,
+                            default:   opt.stringDefaultValue,
+                            pre:       "\u00a0\u00a0", // Unicode nonbreaking space.
+                            value:     []
+                        };
+
+                        if (opt.type == "boolean") {
+                            if (!opt.value)
+                                option.pre = "no";
+                            option.default = (opt.defaultValue ? "" : "no") + opt.name;
+                        }
+                        else if (isArray(opt.value) && opt.type != "charlist")
+                            option.value = ["", "=",
+                                            template.map(opt.value,
+                                                         v => template.highlight(String(v)),
+                                                         ["", ",",
+                                                          ["span", { style: "width: 0; display: inline-block" }, " "]])];
+                        else
+                            option.value = ["", "=", template.highlight(opt.stringValue)];
+                        yield option;
+                    }
+                };
 
-            if (!extraInfo)
-                extraInfo = {};
+                modules.commandline.commandOutput(
+                    template.options("Options", opts.call(this), this["verbose"] > 0));
+            },
 
-            extraInfo.definedAt = contexts.getCaller(Components.stack.caller);
+            cleanup: function cleanup() {
+                for (let opt of this)
+                    if (opt.cleanupValue != null)
+                        opt.stringValue = opt.cleanupValue;
+            },
 
-            let name = names[0];
-            if (name in this._optionMap) {
-                this.dactyl.log(_("option.replaceExisting", name.quote()), 1);
-                this.remove(name);
-            }
+            /**
+             * Adds a new option.
+             *
+             * @param {[string]} names All names for the option.
+             * @param {string} description A description of the option.
+             * @param {string} type The option type (see {@link Option#type}).
+             * @param {value} defaultValue The option's default value.
+             * @param {Object} extra An optional extra configuration hash (see
+             *     {@link Map#extraInfo}).
+             * @optional
+             */
+            add: function add(names, description, type, defaultValue, extraInfo) {
+                if (!util.isDactyl(Components.stack.caller))
+                    deprecated.warn(add, "options.add", "group.options.add");
+
+                util.assert(type in Option.types, _("option.noSuchType", type),
+                            false);
+
+                if (!extraInfo)
+                    extraInfo = {};
+
+                extraInfo.definedAt = contexts.getCaller(Components.stack.caller);
+
+                let name = names[0];
+                if (name in this._optionMap) {
+                    this.dactyl.log(_("option.replaceExisting", JSON.stringify(name)), 1);
+                    this.remove(name);
+                }
 
-            let closure = () => this._optionMap[name];
+                let closure = () => this._optionMap[name];
 
-            memoize(this._optionMap, name,
-                    function () Option.types[type](modules, names, description, defaultValue, extraInfo));
+                memoize(this._optionMap, name,
+                        function () Option.types[type](modules, names, description, defaultValue, extraInfo));
 
-            for (let alias in values(names.slice(1)))
-                memoize(this._optionMap, alias, closure);
+                for (let alias of values(names.slice(1)))
+                    memoize(this._optionMap, alias, closure);
 
-            if (extraInfo.setter && (!extraInfo.scope || extraInfo.scope & Option.SCOPE_GLOBAL))
-                if (this.dactyl.initialized)
-                    closure().initValue();
-                else
-                    memoize(this.needInit, this.needInit.length, closure);
+                if (extraInfo.setter && (!extraInfo.scope || extraInfo.scope & Option.SCOPE_GLOBAL))
+                    if (this.dactyl.initialized)
+                        closure().initValue();
+                    else
+                        memoize(this.needInit, this.needInit.length, closure);
 
-            this._floptions = (this._floptions || []).concat(name);
-            memoize(this._options, this._options.length, closure);
+                this._floptions = (this._floptions || []).concat(name);
+                memoize(this._options, this._options.length, closure);
 
-            // quickly access options with options["wildmode"]:
-            this.__defineGetter__(name, function () this._optionMap[name].value);
-            this.__defineSetter__(name, function (value) { this._optionMap[name].value = value; });
-        }
-    }),
+                // quickly access options with options["wildmode"]:
+                this.__defineGetter__(name, function () this._optionMap[name].value);
+                this.__defineSetter__(name, function (value) { this._optionMap[name].value = value; });
+            }
+        };
+    },
 
     /** @property {Iterator(Option)} @private */
-    __iterator__: function __iterator__()
+    "@@iterator": function __iterator__()
         values(this._options.sort((a, b) => String.localeCompare(a.name, b.name))),
 
     allPrefs: deprecated("prefs.getNames", function allPrefs() prefs.getNames.apply(prefs, arguments)),
@@ -1085,7 +1095,7 @@ var Options = Module("options", {
     remove: function remove(name) {
         let opt = this.get(name);
         this._options = this._options.filter(o => o != opt);
-        for (let name in values(opt.names))
+        for (let name of values(opt.names))
             delete this._optionMap[name];
     },
 
@@ -1120,7 +1130,7 @@ var Options = Module("options", {
 
             let list = [];
             function flushList() {
-                let names = RealSet(list.map(opt => opt.option ? opt.option.name : ""));
+                let names = new RealSet(list.map(opt => opt.option ? opt.option.name : ""));
                 if (list.length)
                     if (list.some(opt => opt.all))
                         options.list(opt => !(list[0].onlyNonDefault && opt.isDefault),
@@ -1131,7 +1141,7 @@ var Options = Module("options", {
                 list = [];
             }
 
-            for (let [, arg] in args) {
+            for (let arg of args) {
                 if (bang) {
                     let onlyNonDefault = false;
                     let reset = false;
@@ -1153,7 +1163,7 @@ var Options = Module("options", {
                         modules.commandline.input(_("pref.prompt.resetAll", config.host) + " ",
                             function (resp) {
                                 if (resp == "yes")
-                                    for (let pref in values(prefs.getNames()))
+                                    for (let pref of values(prefs.getNames()))
                                         prefs.reset(pref);
                             },
                             { promptHighlight: "WarningMsg" });
@@ -1195,7 +1205,7 @@ var Options = Module("options", {
                 if (opt.reset) {
                     flushList();
                     if (opt.all) {
-                        for (let option in modules.options)
+                        for (let option of modules.options)
                             option.reset();
                     }
                     else {
@@ -1301,7 +1311,7 @@ var Options = Module("options", {
 
             // Fill in the current values if we're removing
             if (opt.operator == "-" && isArray(opt.values)) {
-                let have = RealSet((i.text for (i in values(context.allItems.items))));
+                let have = new RealSet(i.text for (i of values(context.allItems.items)));
                 context = context.fork("current-values", 0);
                 context.anchored = optcontext.anchored;
                 context.maxItems = optcontext.maxItems;
@@ -1392,7 +1402,7 @@ var Options = Module("options", {
                             literalArg: [opt.type == "boolean" ? (opt.value ? "" : "no") + opt.name
                                                                : opt.name + "=" + opt.stringValue]
                         }
-                        for (opt in modules.options)
+                        for (opt of modules.options)
                         if (!opt.getter && !opt.isDefault && (opt.scope & Option.SCOPE_GLOBAL))
                     ]
                 }
@@ -1431,7 +1441,7 @@ var Options = Module("options", {
         commands.add(["unl[et]"],
             "Delete a variable",
             function (args) {
-                for (let [, name] in args) {
+                for (let name of args) {
                     name = name.replace(/^g:/, ""); // throw away the scope prefix
                     if (!hasOwnProperty(dactyl._globalVariables, name)) {
                         if (!args.bang)
@@ -1559,7 +1569,7 @@ var Options = Module("options", {
     },
     javascript: function initJavascript(dactyl, modules, window) {
         const { options, JavaScript } = modules;
-        JavaScript.setCompleter(Options.prototype.get, [() => ([o.name, o.description] for (o in options))]);
+        JavaScript.setCompleter(Options.prototype.get, [() => ([o.name, o.description] for (o of options))]);
     },
     sanitizer: function initSanitizer(dactyl, modules, window) {
         const { sanitizer } = modules;
@@ -1568,7 +1578,7 @@ var Options = Module("options", {
             description: "Options containing hostname data",
             action: function sanitize_action(timespan, host) {
                 if (host)
-                    for (let opt in values(modules.options._options))
+                    for (let opt of values(modules.options._options))
                         if (timespan.contains(opt.lastSet * 1000) && opt.domains)
                             try {
                                 opt.value = opt.filterDomain(host, opt.value);
@@ -1578,12 +1588,12 @@ var Options = Module("options", {
                             }
             },
             privateEnter: function privateEnter() {
-                for (let opt in values(modules.options._options))
+                for (let opt of values(modules.options._options))
                     if (opt.privateData && (!callable(opt.privateData) || opt.privateData(opt.value)))
                         opt.oldValue = opt.value;
             },
             privateLeave: function privateLeave() {
-                for (let opt in values(modules.options._options))
+                for (let opt of values(modules.options._options))
                     if (opt.oldValue != null) {
                         opt.value = opt.oldValue;
                         opt.oldValue = null;
diff --git a/common/modules/overlay.jsm b/common/modules/overlay.jsm
index f52a23eb..a3f7cc53 100644
--- a/common/modules/overlay.jsm
+++ b/common/modules/overlay.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2009-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2009-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -37,7 +37,7 @@ var Overlay = Class("Overlay", {
     $: function $(sel, node) DOM(sel, node || this.doc),
 
     cleanup: function cleanup(window, reason) {
-        for (let fn in values(this.cleanups))
+        for (let fn of this.cleanups)
             util.trapErrors(fn, this, window, reason);
     }
 });
@@ -46,8 +46,8 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
     init: function init() {
         util.addObserver(this);
         this.overlays = {};
-
-        this.weakMap = WeakMap();
+        this.overlayMatchers = [];
+        this.weakMap = new WeakMap;
 
         this.onWindowVisible = [];
     },
@@ -75,8 +75,8 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
         else
             [self, events] = [event, event[callback || "events"]];
 
-        for (let [event, callback] in Iterator(events)) {
-            let args = [util.weakReference(target),
+        for (let [event, callback] of iter(events)) {
+            let args = [Cu.getWeakReference(target),
                         event,
                         util.wrapCallback(callback, self),
                         capture,
@@ -113,15 +113,15 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
     },
 
     cleanup: function cleanup(reason) {
-        for (let doc in util.iterDocuments()) {
-            for (let callback in values(this.getData(doc, "cleanup")))
+        for (let doc of util.iterDocuments()) {
+            for (let callback of this.getData(doc, "cleanup"))
                 util.trapErrors(callback, doc, reason);
 
-            for (let elem in values(this.getData(doc, "overlayElements")))
+            for (let elem of this.getData(doc, "overlayElements"))
                 if (elem.parentNode)
                     elem.parentNode.removeChild(elem);
 
-            for (let [elem, ns, name, orig, value] in values(this.getData(doc, "overlayAttributes")))
+            for (let [elem, ns, name, orig, value] of this.getData(doc, "overlayAttributes"))
                 if (getAttr(elem, ns, name) === value)
                     setAttr(elem, ns, name, orig);
 
@@ -192,17 +192,65 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
         delete data[key];
     },
 
+    /**
+     * A curried function which determines which host names match a
+     * given stylesheet filter. When presented with one argument,
+     * returns a matcher function which, given one nsIURI argument,
+     * returns true if that argument matches the given filter. When
+     * given two arguments, returns true if the second argument matches
+     * the given filter.
+     *
+     * @param {string|function(nsIURI):boolean} filter The URI filter to match against.
+     * @param {nsIURI} uri The location to test.
+     * @returns {nsIURI -> boolean}
+     */
+    matchFilter: function matchFilter(filter) {
+        if (typeof filter == "function")
+            var test = filter;
+        else {
+            filter = filter.trim();
+
+            if (filter === "*")
+                var test = function test(uri) true;
+            else if (!/^(?:[a-z-]+:|[a-z-.]+$)/.test(filter)) {
+                let re = util.regexp(filter);
+                test = function test(uri) re.test(uri.spec);
+            }
+            else if (/[*]$/.test(filter)) {
+                let re = RegExp("^" + util.regexp.escape(filter.substr(0, filter.length - 1)));
+                test = function test(uri) re.test(uri.spec);
+                test.re = re;
+            }
+            else if (/[\/:]/.test(filter)) {
+                test = function test(uri) uri.spec === filter;
+                test.exact = true;
+            }
+            else
+                test = function test(uri) { try { return util.isSubdomain(uri.host, filter); } catch (e) { return false; } };
+            test.toString = function toString() filter;
+            test.key = filter;
+        }
+        if (arguments.length < 2)
+            return test;
+        return test(arguments[1]);
+    },
+
     overlayWindow: function overlayWindow(url, fn) {
         if (url instanceof Ci.nsIDOMWindow)
             overlay._loadOverlay(url, fn);
         else {
             Array.concat(url).forEach(function (url) {
-                if (!this.overlays[url])
-                    this.overlays[url] = [];
-                this.overlays[url].push(fn);
+                let matcher = this.matchFilter(url);
+                if (!matcher.exact)
+                    this.overlayMatchers.push([matcher, fn]);
+                else {
+                    if (!this.overlays[url])
+                        this.overlays[url] = [];
+                    this.overlays[url].push(fn);
+                }
             }, this);
 
-            for (let doc in util.iterDocuments())
+            for (let doc of util.iterDocuments())
                 if (~["interactive", "complete"].indexOf(doc.readyState)) {
                     this.observe(doc.defaultView, "xul-window-visible");
                     this._loadOverlays(doc.defaultView);
@@ -215,10 +263,18 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
         }
     },
 
+    getOverlays: function* getOverlays(window) {
+        for (let overlay of this.overlays[window.document.documentURI] || [])
+            yield overlay;
+        for (let [matcher, overlay] of this.overlayMatchers)
+            if (matcher(window.document.documentURIObject))
+                yield overlay;
+    },
+
     _loadOverlays: function _loadOverlays(window) {
-        let overlays = this.getData(window, "overlays");
+        let overlays = this.getData(window.document, "overlays");
 
-        for (let obj of overlay.overlays[window.document.documentURI] || []) {
+        for (let obj of this.getOverlays(window)) {
             if (~overlays.indexOf(obj))
                 continue;
             overlays.push(obj);
@@ -233,19 +289,19 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
 
         function insert(key, fn) {
             if (obj[key]) {
-                let iterator = Iterator(obj[key]);
+                let iterator = iter(obj[key]);
                 if (isArray(obj[key])) {
                     iterator = ([elem[1].id, elem.slice(2), elem[1]]
-                                for each (elem in obj[key]));
+                                for (elem of obj[key]));
                 }
 
-                for (let [elem, xml, attrs] in iterator) {
+                for (let [elem, xml, attrs] of iterator) {
                     if (elem = doc.getElementById(String(elem))) {
                         // Urgh. Hack.
                         let namespaces;
                         if (attrs)
                             namespaces = iter([k.slice(6), DOM.fromJSON.namespaces[v] || v]
-                                              for ([k, v] in Iterator(attrs))
+                                              for ([k, v] of iter(attrs))
                                               if (/^xmlns(?:$|:)/.test(k))).toObject();
 
                         let node = DOM.fromJSON(xml, doc, obj.objects, namespaces);
@@ -253,15 +309,14 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
                         if (!(node instanceof Ci.nsIDOMDocumentFragment))
                             savedElems.push(node);
                         else
-                            for (let n in array.iterValues(node.childNodes))
+                            for (let n of array.iterValues(node.childNodes))
                                 savedElems.push(n);
 
                         fn(elem, node);
 
-                        for (let attr in attrs || []) {
+                        for (let [attr, val] of iter(attrs || {})) {
                             let [ns, localName] = DOM.parseNamespace(attr);
                             let name = attr;
-                            let val = attrs[attr];
 
                             savedAttrs.push([elem, ns, name, getAttr(elem, ns, name), val]);
                             if (name === "highlight")
@@ -425,7 +480,7 @@ var Overlay = Module("Overlay", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReferen
     /**
      * A list of extant dactyl windows.
      */
-    windows: Class.Memoize(() => RealSet())
+    windows: Class.Memoize(() => new RealSet)
 });
 
 endModule();
diff --git a/common/modules/prefs.jsm b/common/modules/prefs.jsm
index 5cdfc9b4..77003108 100644
--- a/common/modules/prefs.jsm
+++ b/common/modules/prefs.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 by Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -57,7 +57,7 @@ var Prefs = Module("prefs", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference])
 
         if (this == prefs) {
             if (~["uninstall", "disable"].indexOf(reason)) {
-                for (let name in values(this.branches.saved.getNames()))
+                for (let name of values(this.branches.saved.getNames()))
                     this.safeReset(name, null, true);
 
                 this.branches.original.resetBranch();
@@ -320,7 +320,7 @@ var Prefs = Module("prefs", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference])
      * @see #withContext
      */
     popContext: function popContext() {
-        for (let [k, v] in Iterator(this._prefContexts.pop()))
+        for (let [k, v] of iter(this._prefContexts.pop()))
             this.set(k, v);
     },
 
@@ -396,8 +396,8 @@ var Prefs = Module("prefs", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference])
 
         let prefArray = this.getNames();
         prefArray.sort();
-        function prefs() {
-            for (let [, pref] in Iterator(prefArray)) {
+        function* prefs() {
+            for (let pref of prefArray) {
                 let userValue = services.pref.prefHasUserValue(pref);
                 if (onlyNonDefault && !userValue || !pref.contains(filter))
                     continue;
diff --git a/common/modules/promises.jsm b/common/modules/promises.jsm
index 9c9618ff..cb0b8d70 100644
--- a/common/modules/promises.jsm
+++ b/common/modules/promises.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -25,10 +25,10 @@ function withCallbacks(fn) {
 }
 
 var Promises = Module("Promises", {
-    _cancel: WeakMap(),
+    _cancel: new WeakMap,
 
     /**
-     * Allows promises to be canceled..
+     * Allows promises to be canceled.
      *
      * @param {Promise} promise The promise to cancel.
      * @param {*} arg Argument to be passed to the cancellation
diff --git a/common/modules/protocol.jsm b/common/modules/protocol.jsm
index 69adb6e1..e6558843 100644
--- a/common/modules/protocol.jsm
+++ b/common/modules/protocol.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -19,11 +19,15 @@ function Channel(url, orig, noErrorChannel, unprivileged) {
         if (url instanceof Ci.nsIChannel)
             return url;
 
-        if (typeof url === "function")
-            return let ([type, data] = url(orig)) StringChannel(data, type, orig);
+        if (typeof url === "function") {
+            let [type, data] = url(orig);
+            return StringChannel(data, type, orig);
+        }
 
-        if (isArray(url))
-            return let ([type, data] = url) StringChannel(data, type, orig);
+        if (isArray(url)) {
+            let [type, data] = url;
+            return StringChannel(data, type, orig);
+        }
 
         let uri = services.io.newURI(url, null, null);
         return (new XMLChannel(uri, null, noErrorChannel)).channel;
@@ -101,7 +105,7 @@ ProtocolBase.prototype = {
     QueryInterface:         XPCOMUtils.generateQI([Ci.nsIProtocolHandler]),
 
     purge: function purge() {
-        for (let doc in util.iterDocuments())
+        for (let doc of util.iterDocuments())
             try {
                 if (doc.documentURIObject.scheme == this.scheme)
                     doc.defaultView.close();
@@ -208,7 +212,7 @@ function XMLChannel(uri, contentType, noErrorChannel, unprivileged) {
             if (!open)
                 this.writes.push("\n]");
 
-            for (let [, pre, url] in util.regexp.iterate(/([^]*?)(?:%include\s+"([^"]*)";|$)/gy, post)) {
+            for (let [, pre, url] of util.regexp.iterate(/([^]*?)(?:%include\s+"([^"]*)";|$)/gy, post)) {
                 this.writes.push(pre);
                 if (url)
                     this.addChannel(url);
diff --git a/common/modules/sanitizer.jsm b/common/modules/sanitizer.jsm
index 8f08a127..a03a133a 100644
--- a/common/modules/sanitizer.jsm
+++ b/common/modules/sanitizer.jsm
@@ -93,7 +93,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
             description: "Cookies",
             persistent: true,
             action: function (range, host) {
-                for (let c in Sanitizer.iterCookies(host))
+                for (let c of Sanitizer.iterCookies(host))
                     if (range.contains(c.creationTime) || timespan.isSession && c.isSession)
                         services.cookies.remove(c.host, c.name, c.path, false);
             },
@@ -140,11 +140,11 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                 if (range.isSession)
                     return;
                 if (host) {
-                    for (let p in Sanitizer.iterPermissions(host)) {
+                    for (let p of Sanitizer.iterPermissions(host)) {
                         services.permissions.remove(util.createURI(p.host), p.type);
                         services.permissions.add(util.createURI(p.host), p.type, 0);
                     }
-                    for (let p in iter(services.contentPrefs.getPrefs(util.createURI(host))))
+                    for (let p of iter(services.contentPrefs.getPrefs(util.createURI(host))))
                         services.contentPrefs.removePref(util.createURI(host), p.QueryInterface(Ci.nsIProperty).name);
                 }
                 else {
@@ -163,7 +163,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
         });
 
         function ourItems(persistent) [
-            item for (item in values(self.itemMap))
+            item for (item of values(self.itemMap))
             if (!item.builtin && (!persistent || item.persistent) && item.name !== "all")
         ];
 
@@ -176,7 +176,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
             ],
             init: function init(win) {
                 let pane = win.document.getElementById("SanitizeDialogPane");
-                for (let [, pref] in iter(pane.preferences))
+                for (let [, pref] of iter(pane.preferences))
                     pref.updateElements();
                 init.superapply(this, arguments);
             }
@@ -184,27 +184,35 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
 
         util.timeout(function () { // Load order issue...
 
-            let (branch = Item.PREFIX + Item.SHUTDOWN_BRANCH) {
+            {
+                let branch = Item.PREFIX + Item.SHUTDOWN_BRANCH;
+
                 overlay.overlayWindow("chrome://browser/content/preferences/sanitize.xul",
-                                      function (win) prefOverlay(branch, true, {
-                    append: {
-                        SanitizeDialogPane:
-                            ["groupbox", { orient: "horizontal", xmlns: "xul" },
-                              ["caption", { label: config.appName + /*L*/" (see :help privacy)" }],
-                              ["grid", { flex: "1" },
-                                ["columns", {},
-                                    ["column", { flex: "1" }],
-                                    ["column", { flex: "1" }]],
-                                ["rows", {},
-                                  let (items = ourItems(true))
-                                     template.map(util.range(0, Math.ceil(items.length / 2)), i =>
-                                         ["row", {},
-                                             template.map(items.slice(i * 2, i * 2 + 2), item =>
-                                                ["checkbox", { xmlns: XUL, label: item.description, preference: branch + item.name }])])]]]
-                    }
-                }));
+                                      function (win) {
+                    let items = ourItems(true);
+
+                    return prefOverlay(branch, true, {
+                        append: {
+                            SanitizeDialogPane:
+                                ["groupbox", { orient: "horizontal", xmlns: "xul" },
+                                  ["caption", { label: config.appName + /*L*/" (see :help privacy)" }],
+                                  ["grid", { flex: "1" },
+                                    ["columns", {},
+                                        ["column", { flex: "1" }],
+                                        ["column", { flex: "1" }]],
+                                    ["rows", {},
+                                         template.map(util.range(0, Math.ceil(items.length / 2)), i =>
+                                             ["row", {},
+                                                 template.map(items.slice(i * 2, i * 2 + 2), item =>
+                                                    ["checkbox", { xmlns: XUL, label: item.description, preference: branch + item.name }])])]]]
+                        }
+                    });
+                });
             }
-            let (branch = Item.PREFIX + Item.BRANCH) {
+
+            {
+                let branch = Item.PREFIX + Item.BRANCH;
+
                 overlay.overlayWindow("chrome://browser/content/sanitize.xul",
                                    function (win) prefOverlay(branch, false, {
                     append: {
@@ -225,7 +233,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                                 self.withSavedValues(["sanitizing"], function () {
                                     self.sanitizing = true;
                                     sanitize.superapply(this, arguments);
-                                    sanitizer.sanitizeItems([item.name for (item in values(self.itemMap))
+                                    sanitizer.sanitizeItems([item.name for (item of values(self.itemMap))
                                                              if (item.shouldSanitize(false))],
                                                             Range.fromArray(this.range || []));
                                 }, this);
@@ -243,7 +251,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
         let item = this.itemMap[name] || Item(name, params);
         this.itemMap[name] = item;
 
-        for (let [k, prop] in iterOwnProperties(params))
+        for (let [k, prop] of iterOwnProperties(params))
             if (!("value" in prop) || !callable(prop.value) && !(k in item))
                 Object.defineProperty(item, k, prop);
 
@@ -252,7 +260,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
             return obj.window || obj;
         }
 
-        let names = RealSet([name].concat(params.contains || []).map(e => "clear-" + e));
+        let names = new RealSet([name].concat(params.contains || []).map(e => "clear-" + e));
         if (params.action)
             storage.addObserver("sanitizer",
                 function (key, event, arg) {
@@ -328,7 +336,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
             this.sanitizing = true;
             let errors = this.sanitizeItems(items, range, null);
 
-            for (let itemName in values(items)) {
+            for (let itemName of values(items)) {
                 try {
                     let item = this.items[Sanitizer.argToPref(itemName)];
                     if (item && !this.itemMap[itemName].override) {
@@ -354,7 +362,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                 items = Object.keys(this.itemMap);
 
             let errors;
-            for (let itemName in values(items))
+            for (let itemName of values(items))
                 try {
                     if (!key || this.itemMap[itemName][key])
                         storage.fireEvent("sanitizer", "clear-" + itemName, [range, host]);
@@ -395,16 +403,16 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
     argToPref: function (arg) Sanitizer.argPrefMap[arg] || arg,
     prefToArg: function (pref) pref.replace(/.*\./, "").toLowerCase(),
 
-    iterCookies: function iterCookies(host) {
-        for (let c in iter(services.cookies, Ci.nsICookie2))
+    iterCookies: function* iterCookies(host) {
+        for (let c of iter(services.cookies, Ci.nsICookie2))
             if (!host || util.isSubdomain(c.rawHost, host) ||
                     c.host[0] == "." && c.host.length < host.length
                         && host.endsWith(c.host))
                 yield c;
 
     },
-    iterPermissions: function iterPermissions(host) {
-        for (let p in iter(services.permissions, Ci.nsIPermission))
+    iterPermissions: function* iterPermissions(host) {
+        for (let p of iter(services.permissions, Ci.nsIPermission))
             if (!host || util.isSubdomain(p.host, host))
                 yield p;
     }
@@ -543,16 +551,16 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                     if (!args.length)
                         args = modules.options["cookies"];
 
-                    for (let [, cmd] in Iterator(args))
+                    for (let cmd of args)
                         switch (cmd) {
                         case "clear":
-                            for (let c in Sanitizer.iterCookies(host))
+                            for (let c of Sanitizer.iterCookies(host))
                                 services.cookies.remove(c.host, c.name, c.path, false);
                             break;
                         case "clear-persistent":
                             session = false;
                         case "clear-session":
-                            for (let c in Sanitizer.iterCookies(host))
+                            for (let c of Sanitizer.iterCookies(host))
                                 if (c.isSession == session)
                                     services.cookies.remove(c.host, c.name, c.path, false);
                             return;
@@ -567,7 +575,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                                   c.path,
                                   c.name,
                                   c.value]
-                                  for (c in Sanitizer.iterCookies(host)))));
+                                  for (c of Sanitizer.iterCookies(host)))));
                             return;
                         default:
                             util.assert(cmd in Sanitizer.PERMS, _("error.invalidArgument"));
@@ -582,7 +590,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                             context.title[1] = "Current Permissions";
                             context.keys.description = function desc(host) {
                                 let count = [0, 0];
-                                for (let c in Sanitizer.iterCookies(host))
+                                for (let c of Sanitizer.iterCookies(host))
                                     count[c.isSession + 0]++;
                                 return [Sanitizer.COMMANDS[getPerms(host)], " (session: ", count[1], " persistent: ", count[0], ")"].join("");
                             };
@@ -622,9 +630,11 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                     return completer.superapply(this, arguments);
                 },
 
-                has: function has(val)
-                    let (res = this.value.find(v => (v == "all" || v.replace(/^!/, "") == val)))
-                        res && !/^!/.test(res),
+                has: function has(val) {
+                    let res = this.value.find(v => (v == "all" || v.replace(/^!/, "") == val));
+
+                    return res && !/^!/.test(res);
+                },
 
                 validator: function (values) values.length &&
                     values.every(val => (val === "all" || hasOwnProperty(sanitizer.itemMap, val.replace(/^!/, ""))))
@@ -635,9 +645,9 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
             "stringlist", "",
             {
                 initialValue: true,
-                get values() [i for (i in values(sanitizer.itemMap)) if (i.persistent || i.builtin)],
+                get values() [i for (i of values(sanitizer.itemMap)) if (i.persistent || i.builtin)],
                 getter: function () !sanitizer.runAtShutdown ? [] : [
-                    item.name for (item in values(sanitizer.itemMap))
+                    item.name for (item of values(sanitizer.itemMap))
                     if (item.shouldSanitize(true))
                 ],
                 setter: function (value) {
@@ -645,8 +655,8 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
                         sanitizer.runAtShutdown = false;
                     else {
                         sanitizer.runAtShutdown = true;
-                        let have = RealSet(value);
-                        for (let item in values(sanitizer.itemMap))
+                        let have = new RealSet(value);
+                        for (let item of values(sanitizer.itemMap))
                             prefs.set(item.shutdownPref,
                                       Boolean(have.has(item.name) ^ have.has("all")));
                     }
diff --git a/common/modules/storage.jsm b/common/modules/storage.jsm
index f1d1a30f..f269b011 100644
--- a/common/modules/storage.jsm
+++ b/common/modules/storage.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -33,7 +33,7 @@ var StoreBase = Class("StoreBase", {
 
         this.__defineGetter__("store", () => store);
         this.__defineGetter__("name", () => name);
-        for (let [k, v] in Iterator(options))
+        for (let [k, v] of iter(options))
             if (this.OPTIONS.indexOf(k) >= 0)
                 this[k] = v;
         this.reload();
@@ -70,7 +70,7 @@ var StoreBase = Class("StoreBase", {
 
     save: function () { (self.storage || storage)._saveData(this); },
 
-    __iterator__: function () Iterator(this._object)
+    "@@iterator": function () iter(this._object)
 });
 
 var ArrayStore = Class("ArrayStore", StoreBase, {
@@ -200,12 +200,14 @@ var Storage = Module("Storage", {
     },
 
     cleanup: function () {
-        this.saveAll();
+        if (this.keys) {
+            this.saveAll();
 
-        for (let key in keys(this.keys)) {
-            if (this[key].timer)
-                this[key].timer.flush();
-            delete this[key];
+            for (let key of keys(this.keys)) {
+                if (this[key].timer)
+                    this[key].timer.flush();
+                delete this[key];
+            }
         }
 
         this.keys = {};
@@ -227,7 +229,7 @@ var Storage = Module("Storage", {
         }
     },
 
-    _saveData: promises.task(function saveData(obj) {
+    _saveData: promises.task(function* saveData(obj) {
         if (obj.privateData && storage.privateMode)
             return;
         if (obj.store && storage.infoPath) {
@@ -302,9 +304,12 @@ var Storage = Module("Storage", {
     },
 
     get observerMaps() {
-        yield this.observers;
-        for (let window of overlay.windows)
-            yield overlay.getData(window, "storage-observers", Object);
+        return function *() {
+            /* FIXME: Symbols */
+            yield this.observers;
+            for (let window of overlay.windows)
+                yield overlay.getData(window, "storage-observers", Object);
+        }.call(this);
     },
 
     addObserver: function addObserver(key, callback, window) {
@@ -313,19 +318,19 @@ var Storage = Module("Storage", {
             observers = overlay.getData(window, "storage-observers", Object);
 
         if (!hasOwnProperty(observers, key))
-            observers[key] = RealSet();
+            observers[key] = new RealSet;
 
         observers[key].add(callback);
     },
 
     removeObserver: function (key, callback) {
-        for (let observers in this.observerMaps)
+        for (let observers of this.observerMaps)
             if (key in observers)
                 observers[key].remove(callback);
     },
 
     fireEvent: function fireEvent(key, event, arg) {
-        for (let observers in this.observerMaps)
+        for (let observers of this.observerMaps)
             for (let observer of observers[key] || [])
                 observer(key, event, arg);
 
@@ -343,8 +348,8 @@ var Storage = Module("Storage", {
             this._saveData(this.keys[key]);
     },
 
-    saveAll: function storeAll() {
-        for each (let obj in this.keys)
+    saveAll: function saveAll() {
+        for (let obj of values(this.keys))
             this._saveData(obj);
     },
 
@@ -361,7 +366,7 @@ var Storage = Module("Storage", {
             else {
                 let { keys } = this;
                 this.keys = {};
-                for (let [k, v] in Iterator(keys))
+                for (let [k, v] of iter(keys))
                     this.keys[k] = this._privatize(v);
             }
         }
@@ -439,12 +444,12 @@ var File = Class("File", {
     /**
      * Iterates over the objects in this directory.
      */
-    iterDirectory: function iterDirectory() {
+    iterDirectory: function* iterDirectory() {
         if (!this.exists())
             throw Error(_("io.noSuchFile"));
         if (!this.isDirectory())
             throw Error(_("io.eNotDir"));
-        for (let file in iter(this.directoryEntries))
+        for (let file of iter(this.directoryEntries))
             yield File(file);
     },
 
@@ -490,7 +495,7 @@ var File = Class("File", {
         if (!this.isDirectory())
             throw Error(_("io.eNotDir"));
 
-        let array = [e for (e in this.iterDirectory())];
+        let array = [e for (e of this.iterDirectory())];
         if (sort)
             array.sort((a, b) => (b.isDirectory() - a.isDirectory() ||
                                   String.localeCompare(a.path, b.path)));
@@ -742,7 +747,7 @@ var File = Class("File", {
         }
     },
 
-    readLines: function readLines(ifstream, encoding) {
+    readLines: function* readLines(ifstream, encoding) {
         try {
             var icstream = services.CharsetStream(
                     ifstream, encoding || File.defaultEncoding, 4096, // buffer size
@@ -783,7 +788,8 @@ var File = Class("File", {
     replacePathSep: function (path) path.replace("/", File.PATH_SEP, "g")
 });
 
-let (file = services.directory.get("ProfD", Ci.nsIFile)) {
+{
+    let file = services.directory.get("ProfD", Ci.nsIFile);
     Object.keys(file).forEach(function (prop) {
         if (!(prop in File.prototype)) {
             let isFunction;
diff --git a/common/modules/styles.jsm b/common/modules/styles.jsm
index 3689c116..c852e379 100644
--- a/common/modules/styles.jsm
+++ b/common/modules/styles.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -13,9 +13,9 @@ lazyRequire("contexts", ["Contexts"]);
 lazyRequire("template", ["template"]);
 
 function cssUri(css) "chrome-data:text/css," + encodeURI(css);
-var namespace = "@namespace html " + XHTML.quote() + ";\n" +
-                "@namespace xul " + XUL.quote() + ";\n" +
-                "@namespace dactyl " + NS.quote() + ";\n";
+var namespace = "@namespace html " + JSON.stringify(XHTML) + ";\n" +
+                "@namespace xul " + JSON.stringify(XUL) + ";\n" +
+                "@namespace dactyl " + JSON.stringify(NS) + ";\n";
 
 var Sheet = Struct("name", "id", "sites", "css", "hive", "agent");
 Sheet.liveProperty = function (name) {
@@ -117,7 +117,7 @@ var Hive = Class("Hive", {
             });
     },
 
-    __iterator__: function () Iterator(this.sheets),
+    "@@iterator": function () iter(this.sheets),
 
     get sites() array(this.sheets).map(s => s.sites)
                                   .flatten()
@@ -189,7 +189,7 @@ var Hive = Class("Hive", {
      */
     find: function find(name, filter, css, index) {
         // Grossly inefficient.
-        let matches = [k for ([k, v] in Iterator(this.sheets))];
+        let matches = [k for ([k, v] of iter(this.sheets))];
         if (index)
             matches = String(index).split(",").filter(i => i in this.sheets);
         if (name)
@@ -230,7 +230,7 @@ var Hive = Class("Hive", {
         if (matches.length == 0)
             return null;
 
-        for (let [, sheet] in Iterator(matches.reverse())) {
+        for (let sheet of matches.reverse()) {
             if (filter) {
                 let sites = sheet.sites.filter(f => f != filter);
                 if (sites.length) {
@@ -294,11 +294,13 @@ var Styles = Module("Styles", {
         return hive;
     },
 
-    __iterator__: function () Iterator(this.user.sheets.concat(this.system.sheets)),
+    "@@iterator": function () iter(this.user.sheets.concat(this.system.sheets)),
 
-    _proxy: function (name, args)
-        let (obj = this[args[0] ? "system" : "user"])
-            obj[name].apply(obj, Array.slice(args, 1)),
+    _proxy: function (name, args) {
+        let obj = this[args[0] ? "system" : "user"];
+
+        return obj[name].apply(obj, Array.slice(args, 1));
+    },
 
     addSheet: deprecated("Styles#{user,system}.add", function addSheet() this._proxy("add", arguments)),
     findSheets: deprecated("Styles#{user,system}.find", function findSheets() this._proxy("find", arguments)),
@@ -336,16 +338,19 @@ var Styles = Module("Styles", {
                 ["col", { style: "min-width: 1em; text-align: center; color: red; font-weight: bold;" }],
                 ["col", { style: "padding: 0 1em 0 1ex; vertical-align: top;" }],
                 ["col", { style: "padding: 0 1em 0 0; vertical-align: top;" }],
-                template.map(hives, hive => let (i = 0) [
-                    ["tr", { style: "height: .5ex;" }],
-                    template.map(sheets(hive), sheet =>
-                        ["tr", {},
-                            ["td", { highlight: "Title" }, !i++ ? hive.name : ""],
-                            ["td", {}, sheet.enabled ? "" : UTF8("×")],
-                            ["td", {}, sheet.name || hive.sheets.indexOf(sheet)],
-                            ["td", {}, sheet.formatSites(uris)],
-                            ["td", {}, sheet.css]]),
-                    ["tr", { style: "height: .5ex;" }]])];
+                template.map(hives, hive => {
+                    let i = 0;
+                    return [
+                        ["tr", { style: "height: .5ex;" }],
+                        template.map(sheets(hive), sheet =>
+                            ["tr", {},
+                                ["td", { highlight: "Title" }, !i++ ? hive.name : ""],
+                                ["td", {}, sheet.enabled ? "" : UTF8("×")],
+                                ["td", {}, sheet.name || hive.sheets.indexOf(sheet)],
+                                ["td", {}, sheet.formatSites(uris)],
+                                ["td", {}, sheet.css]]),
+                        ["tr", { style: "height: .5ex;" }]];
+                })];
 
         // E4X-FIXME
         // // TODO: Move this to an ItemList to show this automatically
@@ -375,7 +380,7 @@ var Styles = Module("Styles", {
     append: function (dest, src, sort) {
         let props = {};
         for (let str of [dest, src])
-            for (let prop in Styles.propertyIter(str))
+            for (let prop of Styles.propertyIter(str))
                 props[prop.name] = prop.value;
 
         let val = Object.keys(props)[sort ? "sort" : "slice"]()
@@ -450,7 +455,7 @@ var Styles = Module("Styles", {
     },
 
     splitContext: function splitContext(context, title) {
-        for (let item in Iterator({ Active: true, Inactive: false })) {
+        for (let item of iter({ Active: true, Inactive: false })) {
             let [name, active] = item;
             context.split(name, null, function (context) {
                 context.title[0] = /*L*/name + " " + (title || "Sheets");
@@ -459,9 +464,10 @@ var Styles = Module("Styles", {
         }
     },
 
-    propertyIter: function (str, always) {
+    propertyIter: function* (str, always) {
         let i = 0;
-        for (let match in this.propertyPattern.iterate(str)) {
+        let x = /The status bar/.test(str);
+        for (let match of this.propertyPattern.iterate(str)) {
             if (match.value || always && match.name || match.wholeMatch === match.preSpace && always && !i++)
                 yield match;
             if (!/;/.test(match.postSpace))
@@ -729,7 +735,7 @@ var Styles = Module("Styles", {
             context.keys = { text: function (p) p + ":",
                              description: function () "" };
 
-            for (let match in Styles.propertyIter(context.filter, true))
+            for (let match of Styles.propertyIter(context.filter, true))
                 var lastMatch = match;
 
             if (lastMatch != null && !lastMatch.value && !lastMatch.postSpace) {
diff --git a/common/modules/template.jsm b/common/modules/template.jsm
index 39a42ffd..3fdb6fc2 100644
--- a/common/modules/template.jsm
+++ b/common/modules/template.jsm
@@ -1,4 +1,4 @@
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k at Gmail>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k at Gmail>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -20,7 +20,7 @@ var Binding = Class("Binding", {
 
         Object.defineProperties(node, this.constructor.properties);
 
-        for (let [event, handler] in values(this.constructor.events))
+        for (let [event, handler] of values(this.constructor.events))
             node.addEventListener(event, util.wrapCallback(handler, true), false);
     },
 
@@ -41,9 +41,12 @@ var Binding = Class("Binding", {
     })
 }, {
     get bindings() {
-        let bindingProto = Object.getPrototypeOf(Binding.prototype);
-        for (let obj = this.prototype; obj !== bindingProto; obj = Object.getPrototypeOf(obj))
-            yield obj;
+        return function* () {
+            let bindingProto = Object.getPrototypeOf(Binding.prototype);
+            for (let obj = this.prototype; obj !== bindingProto; obj = Object.getPrototypeOf(obj))
+                /* FIXME: Symbols */
+                yield obj;
+        }.call(this);
     },
 
     bind: function bind(func) function bound() {
@@ -58,20 +61,20 @@ var Binding = Class("Binding", {
 
     events: Class.Memoize(function () {
         let res = [];
-        for (let obj in this.bindings)
+        for (let obj of this.bindings)
             if (Object.getOwnPropertyDescriptor(obj, "events"))
-                for (let [event, handler] in Iterator(obj.events))
+                for (let [event, handler] of iter(obj.events))
                     res.push([event, this.bind(handler)]);
         return res;
     }),
 
     properties: Class.Memoize(function () {
         let res = {};
-        for (let obj in this.bindings)
-            for (let prop in properties(obj)) {
+        for (let obj of this.bindings)
+            for (let prop of properties(obj)) {
                 let desc = Object.getOwnPropertyDescriptor(obj, prop);
                 if (desc.enumerable) {
-                    for (let k in values(["get", "set", "value"]))
+                    for (let k of values(["get", "set", "value"]))
                         if (typeof desc[k] === "function")
                             desc[k] = this.bind(desc[k]);
                     res[prop] = desc;
@@ -143,19 +146,19 @@ var Template = Module("Template", {
                 if (hasOwnProperty(events, "input"))
                     events["dactyl-input"] = events["input"];
 
-                for (let [event, handler] in Iterator(events))
+                for (let [event, handler] of iter(events))
                     node.addEventListener(event, util.wrapCallback(handler.bind(obj), true), false);
             }
         })
     },
 
-    map: function map(iter, func, sep, interruptable) {
-        if (typeof iter.length == "number") // FIXME: Kludge?
-            iter = array.iterValues(iter);
+    map: function map(iter_, func, sep, interruptable) {
+        if (typeof iter_.length == "number") // FIXME: Kludge?
+            iter_ = array.iterValues(iter_);
 
         let res = [];
         let n = 0;
-        for (let i in Iterator(iter)) {
+        for (let i of iter_) {
             let val = func(i, n);
             if (val == undefined)
                 continue;
@@ -257,8 +260,8 @@ var Template = Module("Template", {
             (?P<tag> '[\w-]+' | :(?:[\w-]+!?|!) | (?:._)?<[\w-]+>\w* | \b[a-zA-Z]_(?:[\w[\]]+|.) | \[[\w-;]+\] | E\d{3} )
             (?=      [[\)!,:;./\s]|$)
         */$), "gx");
-        return this.highlightSubstrings(str, (function () {
-            for (let res in re.iterate(str))
+        return this.highlightSubstrings(str, (function* () {
+            for (let res of re.iterate(str))
                 yield [res.index + res.pre.length, res.tag.length];
         })(), this[help ? "HelpLink" : "helpLink"]);
     },
@@ -276,7 +279,7 @@ var Template = Module("Template", {
                 return ["span", { highlight: "Number" }, str];
             case "string":
                 if (processStrings)
-                    str = str.quote();
+                    str = JSON.stringify(str);
                 return ["span", { highlight: "String" }, str];
             case "boolean":
                 return ["span", { highlight: "Boolean" }, str];
@@ -318,7 +321,7 @@ var Template = Module("Template", {
         if (isURI)
             str = util.losslessDecodeURI(str);
 
-        return this.highlightSubstrings(str, (function () {
+        return this.highlightSubstrings(str, (function* () {
             if (filter.length == 0)
                 return;
 
@@ -333,13 +336,13 @@ var Template = Module("Template", {
     },
 
     highlightRegexp: function highlightRegexp(str, re, highlight) {
-        return this.highlightSubstrings(str, (function () {
-            for (let res in util.regexp.iterate(re, str))
+        return this.highlightSubstrings(str, (function* () {
+            for (let res of util.regexp.iterate(re, str))
                 yield [res.index, res[0].length, res.wholeMatch ? [res] : res];
         })(), highlight || template.filter);
     },
 
-    highlightSubstrings: function highlightSubstrings(str, iter, highlight) {
+    highlightSubstrings: function highlightSubstrings(str, iter_, highlight) {
         if (!isString(str))
             return str;
 
@@ -349,7 +352,7 @@ var Template = Module("Template", {
         let s = [""];
         let start = 0;
         let n = 0, _i;
-        for (let [i, length, args] in iter) {
+        for (let [i, length, args] of iter_) {
             if (i == _i || i < _i)
                 break;
             _i = i;
@@ -468,19 +471,22 @@ var Template = Module("Template", {
                     this.map(format.columns, (c) => ["col", { style: c }])] :
                 [],
             ["tbody", { highlight: "UsageBody" },
-                this.map(iter, (item) =>
+                this.map(iter, (item) => {
                     // Urgh.
-                    let (name = item.name || item.names[0], frame = item.definedAt)
-                        ["tr", { highlight: "UsageItem" },
-                            ["td", { style: "padding-right: 2em;" },
-                                ["span", { highlight: "Usage Link" },
-                                    !frame ? name :
-                                        [this.helpLink(help(item), name, "Title"),
-                                         ["span", { highlight: "LinkInfo" },
-                                            _("io.definedAt"), " ",
-                                            sourceLink(frame)]]]],
-                            item.columns ? this.map(item.columns, (c) => ["td", {}, c]) : [],
-                            ["td", {}, desc(item)]])]];
+                    let name = item.name || item.names[0];
+                    let frame = item.definedAt;
+
+                    return ["tr", { highlight: "UsageItem" },
+                               ["td", { style: "padding-right: 2em;" },
+                                   ["span", { highlight: "Usage Link" },
+                                       !frame ? name :
+                                           [this.helpLink(help(item), name, "Title"),
+                                            ["span", { highlight: "LinkInfo" },
+                                               _("io.definedAt"), " ",
+                                               sourceLink(frame)]]]],
+                               item.columns ? this.map(item.columns, (c) => ["td", {}, c]) : [],
+                               ["td", {}, desc(item)]];
+                })]];
     }
 });
 
diff --git a/common/modules/util.jsm b/common/modules/util.jsm
index 5199a69b..95493500 100644
--- a/common/modules/util.jsm
+++ b/common/modules/util.jsm
@@ -1,6 +1,6 @@
 // Copyright (c) 2006-2008 by Martin Stubenschrott <stubenschrott@vimperator.org>
 // Copyright (c) 2007-2011 Doug Kearns <dougkearns@gmail.com>
-// Copyright (c) 2008-2014 Kris Maglione <maglione.k@gmail.com>
+// Copyright (c) 2008-2015 Kris Maglione <maglione.k@gmail.com>
 //
 // This work is licensed for reuse under an MIT license. Details are
 // given in the LICENSE.txt file included with this file.
@@ -137,7 +137,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         let cleanup = ["dactyl-cleanup-modules", "quit-application"];
 
         function register(meth) {
-            for (let target of RealSet(cleanup.concat(Object.keys(obj.observers))))
+            for (let target of new RealSet(cleanup.concat(Object.keys(obj.observers))))
                 try {
                     services.observer[meth](obj, target, true);
                 }
@@ -208,10 +208,10 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
 
         // check for chars not in the accepted range
         this.assert(RegExp("^[" + accepted + "-]+$").test(list),
-                    _("error.charactersOutsideRange", accepted.quote()));
+                    _("error.charactersOutsideRange", JSON.stringify(accepted)));
 
         // check for illegal ranges
-        for (let [match] in this.regexp.iterate(/.-./g, list))
+        for (let [match] of this.regexp.iterate(/.-./g, list))
             this.assert(match.charCodeAt(0) <= match.charCodeAt(2),
                         _("error.invalidCharacterRange", list.slice(list.indexOf(match))));
 
@@ -228,7 +228,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         if (isArray(obj))
             return obj.slice();
         let newObj = {};
-        for (let [k, v] in Iterator(obj))
+        for (let [k, v] of iter(obj))
             newObj[k] = v;
         return newObj;
     },
@@ -272,7 +272,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
             });
 
         let end = 0;
-        for (let match in util.regexp.iterate(/(.*?)%(.)/gy, format)) {
+        for (let match of util.regexp.iterate(/(.*?)%(.)/gy, format)) {
 
             let [, prefix, char] = match;
             end += match[0].length;
@@ -301,7 +301,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                                                      : "",
                     { test: function test(obj) obj[char] != null }));
 
-                for (let elem in array.iterValues(stack))
+                for (let elem of array.iterValues(stack))
                     elem.seen[char] = true;
             }
         }
@@ -353,7 +353,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                     : "",
             {
                 elements: [],
-                seen: RealSet(),
+                seen: new RealSet,
                 valid: function valid(obj) this.elements.every(e => (!e.test || e.test(obj)))
             });
 
@@ -369,7 +369,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         */$), "gixy");
         macro = String(macro);
         let end = 0;
-        for (let match in re.iterate(macro)) {
+        for (let match of re.iterate(macro)) {
             let [, prefix, open, full, macro, idx, close] = match;
             end += match[0].length;
 
@@ -386,7 +386,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
             }
             else {
                 let [, flags, name] = /^((?:[a-z]-)*)(.*)/.exec(macro);
-                flags = RealSet(flags);
+                flags = new RealSet(flags);
 
                 let quote = util.identity;
                 if (flags.has("q"))
@@ -420,7 +420,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                             }));
                     }
 
-                    for (let elem in array.iterValues(stack))
+                    for (let elem of array.iterValues(stack))
                         elem.seen.add(name);
                 }
             }
@@ -474,7 +474,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                         if (acc.length == pattern.length)
                             this.res.push(acc.join(""));
                         else
-                            for (let val in values(vals))
+                            for (let val of values(vals))
                                 this.rec(acc.concat(val));
                     }
                 });
@@ -510,7 +510,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                 if (acc.length == patterns.length)
                     res.push(array(substrings).zip(acc).flatten().join(""));
                 else
-                    for (let [, pattern] in Iterator(patterns[acc.length]))
+                    for (let [, pattern] of Iterator(patterns[acc.length]))
                         rec(acc.concat(pattern));
             };
             rec([]);
@@ -766,7 +766,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
 
             if (isObject(params.params)) {
                 let data = [encodeURIComponent(k) + "=" + encodeURIComponent(v)
-                            for ([k, v] in iter(params.params))];
+                            for ([k, v] of iter(params.params))];
                 let uri = util.newURI(url);
                 uri.query += (uri.query ? "&" : "") + data.join("&");
 
@@ -775,7 +775,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
 
             if (isObject(params.data) && !(params.data instanceof Ci.nsISupports)) {
                 let data = services.FormData();
-                for (let [k, v] in iter(params.data))
+                for (let [k, v] of iter(params.data))
                     data.append(k, v);
                 params.data = data;
             }
@@ -801,7 +801,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                 args.push(prams.pass);
             xmlhttp.open.apply(xmlhttp, args);
 
-            for (let [header, val] in Iterator(params.headers || {}))
+            for (let [header, val] of iter(params.headers || {}))
                 xmlhttp.setRequestHeader(header, val);
 
             if (params.responseType)
@@ -899,7 +899,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      * Iterates over all currently open documents, including all
      * top-level window and sub-frames thereof.
      */
-    iterDocuments: function iterDocuments(types) {
+    iterDocuments: function* iterDocuments(types) {
         types = types ? types.map(s => "type" + util.capitalize(s))
                       : ["typeChrome", "typeContent"];
 
@@ -909,11 +909,11 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
             for (let type of types) {
                 let docShells = window.docShell.getDocShellEnumerator(Ci.nsIDocShellTreeItem[type],
                                                                       Ci.nsIDocShell.ENUMERATE_FORWARDS);
-                while (docShells.hasMoreElements())
-                    let (viewer = docShells.getNext().QueryInterface(Ci.nsIDocShell).contentViewer) {
-                        if (viewer)
-                            yield viewer.DOMDocument;
-                    };
+                while (docShells.hasMoreElements()) {
+                    let viewer = docShells.getNext().QueryInterface(Ci.nsIDocShell).contentViewer;
+                    if (viewer)
+                        yield viewer.DOMDocument;
+                }
             }
         }
     },
@@ -956,22 +956,16 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      * @returns {string} The DTD fragment containing entity declaration
      *      for *obj*.
      */
-    makeDTD: let (map = { "'": "&apos;", '"': "&quot;", "%": "&#x25;", "&": "&amp;", "<": "&lt;", ">": "&gt;" })
-        function makeDTD(obj) {
-            function escape(val) {
-               let isDOM = DOM.isJSONXML(val);
-               return String.replace(val == null ? "null" :
-                                     isDOM       ? DOM.toXML(val)
-                                                 : val,
-                                     isDOM ? /['%]/g
-                                           : /['"%&<>]/g,
-                                     m => map[m]);
-            }
-
-            return iter(obj).map(([k, v]) =>
-                                 ["<!ENTITY ", k, " '", escape(v), "'>"].join(""))
-                            .join("\n");
-        },
+    makeDTD: function makeDTD(obj) {
+        let map = { "'": "&apos;", '"': "&quot;", "%": "&#x25;", "&": "&amp;", "<": "&lt;", ">": "&gt;" };
+
+        return iter(obj)
+          .map(([k, v]) => ["<!ENTITY ", k, " '", String.replace(v == null ? "null" : typeof v == "xml" ? v.toXMLString() : v,
+                                                                 typeof v == "xml" ? /['%]/g : /['"%&<>]/g,
+                                                                 function (m) map[m]),
+                            "'>"].join(""))
+          .join("\n");
+    },
 
     /**
      * Converts a URI string into a URI object.
@@ -1014,7 +1008,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         if (!isObject(object))
             return String(object);
 
-        if (object instanceof Ci.nsIDOMElement) {
+        if (object instanceof Ci.nsIDOMElement || object instanceof DOM) {
             let elem = object;
             if (elem.nodeType == elem.TEXT_NODE)
                 return elem.data;
@@ -1039,26 +1033,22 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         else
             head = util.clip(obj, 150).replace(/\n/g, "^J") + "::\n";
 
-        let keys = [];
+        let keys_ = [];
 
         // window.content often does not want to be queried with "var i in object"
         try {
-            let hasValue = !("__iterator__" in object || isinstance(object, ["Generator", "Iterator"]));
+            if (isArray(object))
+                object = iter(object);
+
+            let hasValue = !(Symbol.iterator in object || isinstance(object, ["Generator", "Iterator", Iter]));
+            let keyIter = hasValue ? keys(object) : object;
 
             if (object.dactyl && object.modules && object.modules.modules == object.modules) {
                 object = Iterator(object);
                 hasValue = false;
             }
 
-            let keyIter = object;
-            if (iter.iteratorProp in object) {
-                keyIter = (k for (k of object));
-                hasValue = false;
-            }
-            else if ("__iterator__" in object && !callable(object.__iterator__))
-                keyIter = keys(object);
-
-            for (let i in keyIter) {
+            for (let i of keyIter) {
                 let value = Magic("<no value>");
                 try {
                     value = object[i];
@@ -1094,7 +1084,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                 else
                     val = key + ": " + value;
 
-                keys.push([i, val]);
+                keys_.push([i, val]);
             }
         }
         catch (e) {
@@ -1108,7 +1098,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                                         String(b[0]));
         }
 
-        let vals = template.map(keys.sort(compare), f => f[1],
+        let vals = template.map(keys_.sort(compare), f => f[1],
                                 "\n");
 
         if (color) {
@@ -1122,7 +1112,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
 
         function rec(data, level, seen) {
             if (isObject(data)) {
-                seen = RealSet(seen);
+                seen = new RealSet(seen);
                 if (seen.add(data))
                     throw Error("Recursive object passed");
             }
@@ -1141,7 +1131,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                     res.push("[]");
                 else {
                     res.push("[\n");
-                    for (let [i, val] in Iterator(data)) {
+                    for (let [i, val] of iter(data)) {
                         if (i)
                             res.push(",\n");
                         res.push(prefix);
@@ -1154,7 +1144,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                 res.push("{\n");
 
                 let i = 0;
-                for (let [key, val] in Iterator(data)) {
+                for (let [key, val] of iter(data)) {
                     if (i++)
                         res.push(",\n");
                     res.push(prefix, JSON.stringify(key), ": ");
@@ -1172,7 +1162,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         }
 
         let res = [];
-        rec(data, "", RealSet());
+        rec(data, "", new RealSet);
         return res.join("");
     },
 
@@ -1180,7 +1170,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         "dactyl-cleanup-modules": function cleanupModules(subject, reason) {
             defineModule.loadLog.push("dactyl: util: observe: dactyl-cleanup-modules " + reason);
 
-            for (let module in values(defineModule.modules))
+            for (let module of values(defineModule.modules))
                 if (module.cleanup) {
                     util.dump("cleanup: " + module.constructor.className);
                     util.trapErrors(module.cleanup, module, reason);
@@ -1198,7 +1188,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      *     negative. @default 1
      * @returns {Iterator(Object)}
      */
-    range: function range(start, end, step) {
+    range: function* range(start, end, step) {
         if (!step)
             step = 1;
         if (step > 0) {
@@ -1220,7 +1210,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      * @param {number} time The time in milliseconds between thread yields.
      * @returns {Iterator(Object)}
      */
-    interruptibleRange: function interruptibleRange(start, end, time) {
+    interruptibleRange: function* interruptibleRange(start, end, time) {
         let endTime = Date.now() + time;
         while (start < end) {
             if (Date.now() > endTime) {
@@ -1249,7 +1239,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      * @returns {RegExp} A custom regexp object.
      */
     regexp: update(function (expr, flags, tokens) {
-        flags = flags || [k for ([k, v] in Iterator({ g: "global", i: "ignorecase", m: "multiline", y: "sticky" }))
+        flags = flags || [k for ([k, v] of iter({ g: "global", i: "ignorecase", m: "multiline", y: "sticky" }))
                           if (expr[v])].join("");
 
         if (isinstance(expr, ["RegExp"]))
@@ -1302,8 +1292,13 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         // have them.
         if (struct)
             update(res, {
-                exec: function exec() let (match = exec.superapply(this, arguments)) match && struct.fromArray(match),
-                dactylSource: source, struct: struct
+                exec: function exec() {
+                    let match = exec.superapply(this, arguments);
+
+                    return match && struct.fromArray(match);
+                },
+                dactylSource: source,
+                struct: struct
             });
         return res;
     }, {
@@ -1333,17 +1328,19 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
          * @param {string} string The string to search.
          * @param {number} lastIndex The index at which to begin searching. @optional
          */
-        iterate: function iterate(regexp, string, lastIndex) iter(function () {
-            regexp.lastIndex = lastIndex = lastIndex || 0;
-            let match;
-            while (match = regexp.exec(string)) {
-                lastIndex = regexp.lastIndex;
-                yield match;
-                regexp.lastIndex = lastIndex;
-                if (match[0].length == 0 || !regexp.global)
-                    break;
-            }
-        }())
+        iterate: function iterate(regexp, string, lastIndex) {
+            return iter(new function* () {
+                regexp.lastIndex = lastIndex = lastIndex || 0;
+                let match;
+                while (match = regexp.exec(string)) {
+                    lastIndex = regexp.lastIndex;
+                    yield match;
+                    regexp.lastIndex = lastIndex;
+                    if (match[0].length == 0 || !regexp.global)
+                        break;
+                }
+            });
+        }
     }),
 
     /**
@@ -1400,7 +1397,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
 
             this.errors.push([new Date, obj + "\n" + obj.stack]);
             this.errors = this.errors.slice(-this.maxErrors);
-            this.errors.toString = function () [k + "\n" + v for ([k, v] in array.iterValues(this))].join("\n\n");
+            this.errors.toString = function () [k + "\n" + v for ([k, v] of array.iterValues(this))].join("\n\n");
 
             this.dump(String(error));
             this.dump(obj);
@@ -1437,7 +1434,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         catch (e) {}
 
         let ary = host.split(".");
-        ary = [ary.slice(i).join(".") for (i in util.range(ary.length, 0, -1))];
+        ary = [ary.slice(i).join(".") for (i of util.range(ary.length, 0, -1))];
         return ary.filter(h => h.length >= base.length);
     },
 
@@ -1658,11 +1655,11 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      * @param {function} func The function to call
      * @param {object} self The 'this' object for the function.
      */
-    trapErrors: function trapErrors(func, self, ...args) {
+    trapErrors: function trapErrors(func, self) {
         try {
             if (!callable(func))
                 func = self[func];
-            return func.apply(self || this, args);
+            return func.apply(self || this, Array.slice(arguments, 2));
         }
         catch (e) {
             this.reportError(e);
@@ -1697,7 +1694,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      */
     visibleHosts: function visibleHosts(win) {
         let res = [],
-            seen = RealSet();
+            seen = new RealSet;
         (function rec(frame) {
             try {
                 if (frame.location.hostname)
@@ -1718,7 +1715,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      */
     visibleURIs: function visibleURIs(win) {
         let res = [],
-            seen = RealSet();
+            seen = new RealSet;
         (function rec(frame) {
             try {
                 res = res.concat(util.newURI(frame.location.href));