From 79148d2940a82088f08771e1271de4d7d68e3551 Mon Sep 17 00:00:00 2001
From: satyr <murky.satyr@gmail.com>
Date: Wed, 13 Oct 2010 20:29:22 +0900
Subject: [PATCH] refactored loop variable caching

---
 Cakefile                        |   4 +-
 lib/browser.js                  |  22 +--
 lib/cake.js                     |   6 +-
 lib/coffee-script.js            |   2 +-
 lib/command.js                  |  70 +++++-----
 lib/grammar.js                  |  18 +--
 lib/helpers.js                  |   4 +-
 lib/lexer.js                    |  10 +-
 lib/nodes.js                    | 238 +++++++++++++-------------------
 lib/optparse.js                 |  14 +-
 lib/rewriter.js                 |  38 ++---
 lib/scope.js                    |  16 +--
 src/browser.coffee              |   2 +-
 src/grammar.coffee              |  18 +--
 src/nodes.coffee                | 106 +++++++-------
 test/test_comprehensions.coffee |  49 -------
 16 files changed, 257 insertions(+), 360 deletions(-)

diff --git a/Cakefile b/Cakefile
index 601bef19..2fa46891 100644
--- a/Cakefile
+++ b/Cakefile
@@ -99,8 +99,8 @@ task 'loc', 'count the lines of source code in the CoffeeScript compiler', ->
 runTests = (CoffeeScript) ->
   startTime = Date.now()
   passedTests = failedTests = 0
-  for all name, func of require 'assert'
-    global[name] = -> ++passedTests; func arguments...
+  wrap = (name, func) -> global[name] = -> ++passedTests; func arguments...
+  wrap name, func for all name, func of require 'assert'
   global.eq = global.strictEqual
   global.CoffeeScript = CoffeeScript
   process.on 'exit', ->
diff --git a/lib/browser.js b/lib/browser.js
index e95f39f5..05d4ee2b 100644
--- a/lib/browser.js
+++ b/lib/browser.js
@@ -6,7 +6,7 @@
     return eval(CoffeeScript.compile(code, options));
   };
   CoffeeScript.run = function(code, options) {
-    ((options != null) ? options.bare = true : undefined);
+    (options != null) ? options.bare = true : undefined;
     return Function(CoffeeScript.compile(code, options))();
   };
   if (!(typeof window !== "undefined" && window !== null)) {
@@ -25,16 +25,16 @@
     return xhr.send(null);
   };
   runScripts = function() {
-    var _i, _j, _len, _ref, script;
-    for (_i = 0, _len = (_ref = document.getElementsByTagName('script')).length; _i < _len; _i++) {
-      (function() {
-        var script = _ref[_i];
-        _j = script;
-        return script.type === 'text/coffeescript' ? script.src ? CoffeeScript.load(script.src) : setTimeout(function() {
-          return CoffeeScript.run(script.innerHTML);
-        }) : undefined;
-      })();
-      script = _j;
+    var _i, _len, _ref, script;
+    for (_i = 0, _len = (_ref = document.getElementsByTagName('script')).length; _i < _len; ++_i) {
+      script = _ref[_i];
+      if (script.type === 'text/coffeescript') {
+        if (script.src) {
+          CoffeeScript.load(script.src);
+        } else {
+          CoffeeScript.run(script.innerHTML);
+        }
+      }
     }
     return null;
   };
diff --git a/lib/cake.js b/lib/cake.js
index 395a9a41..ebd90294 100755
--- a/lib/cake.js
+++ b/lib/cake.js
@@ -15,11 +15,11 @@
       if (!action) {
         _ref = [description, action], action = _ref[0], description = _ref[1];
       }
-      return (tasks[name] = {
+      return tasks[name] = {
         name: name,
         description: description,
         action: action
-      });
+      };
     },
     option: function(letter, flag, description) {
       return switches.push([letter, flag, description]);
@@ -47,7 +47,7 @@
       }
       options = oparse.parse(args);
       _result = [];
-      for (_i = 0, _len = (_ref = options.arguments).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref = options.arguments).length; _i < _len; ++_i) {
         arg = _ref[_i];
         _result.push(invoke(arg));
       }
diff --git a/lib/coffee-script.js b/lib/coffee-script.js
index 000acf46..7b3894bb 100755
--- a/lib/coffee-script.js
+++ b/lib/coffee-script.js
@@ -64,7 +64,7 @@
     },
     setInput: function(tokens) {
       this.tokens = tokens;
-      return (this.pos = 0);
+      return this.pos = 0;
     },
     upcomingInput: function() {
       return "";
diff --git a/lib/command.js b/lib/command.js
index 9eb2aaa9..1cf8b242 100644
--- a/lib/command.js
+++ b/lib/command.js
@@ -48,43 +48,39 @@
     return compileScripts();
   };
   compileScripts = function() {
-    var _i, _j, _len, _ref2, _result, base, compile, source;
+    var _i, _len, _ref2, _result, base, compile, source;
     _result = [];
-    for (_i = 0, _len = (_ref2 = sources).length; _i < _len; _i++) {
-      (function() {
-        var source = _ref2[_i];
-        _j = source;
-        return _result.push((function() {
-          base = path.join(source);
-          compile = function(source, topLevel) {
-            return path.exists(source, function(exists) {
-              if (!exists) {
-                throw new Error("File not found: " + source);
+    for (_i = 0, _len = (_ref2 = sources).length; _i < _len; ++_i) {
+      source = _ref2[_i];
+      _result.push((function() {
+        base = path.join(source);
+        compile = function(source, topLevel) {
+          return path.exists(source, function(exists) {
+            if (!exists) {
+              throw new Error("File not found: " + source);
+            }
+            return fs.stat(source, function(err, stats) {
+              if (stats.isDirectory()) {
+                return fs.readdir(source, function(err, files) {
+                  var _j, _len2, _result2, file;
+                  _result2 = [];
+                  for (_j = 0, _len2 = files.length; _j < _len2; ++_j) {
+                    file = files[_j];
+                    _result2.push(compile(path.join(source, file)));
+                  }
+                  return _result2;
+                });
+              } else if (topLevel || path.extname(source) === '.coffee') {
+                fs.readFile(source, function(err, code) {
+                  return compileScript(source, code.toString(), base);
+                });
+                return opts.watch ? watch(source, base) : undefined;
               }
-              return fs.stat(source, function(err, stats) {
-                if (stats.isDirectory()) {
-                  return fs.readdir(source, function(err, files) {
-                    var _k, _len2, _result2, file;
-                    _result2 = [];
-                    for (_k = 0, _len2 = files.length; _k < _len2; _k++) {
-                      file = files[_k];
-                      _result2.push(compile(path.join(source, file)));
-                    }
-                    return _result2;
-                  });
-                } else if (topLevel || path.extname(source) === '.coffee') {
-                  fs.readFile(source, function(err, code) {
-                    return compileScript(source, code.toString(), base);
-                  });
-                  return opts.watch ? watch(source, base) : undefined;
-                }
-              });
             });
-          };
-          return compile(source, true);
-        })());
-      })();
-      source = _j;
+          });
+        };
+        return compile(source, true);
+      })());
     }
     return _result;
   };
@@ -93,7 +89,7 @@
     o = opts;
     options = compileOptions(file);
     if (o.require) {
-      for (_i = 0, _len = (_ref2 = o.require).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = o.require).length; _i < _len; ++_i) {
         req = _ref2[_i];
         require(helpers.starts(req, '.') ? fs.realpathSync(req) : req);
       }
@@ -190,7 +186,7 @@
     var _i, _len, _ref2, _result, strings, tag, token, value;
     strings = (function() {
       _result = [];
-      for (_i = 0, _len = tokens.length; _i < _len; _i++) {
+      for (_i = 0, _len = tokens.length; _i < _len; ++_i) {
         token = tokens[_i];
         _result.push((function() {
           _ref2 = [token[0], token[1].toString().replace(/\n/, '\\n')], tag = _ref2[0], value = _ref2[1];
@@ -208,7 +204,7 @@
     o.compile || (o.compile = !!o.output);
     o.run = !(o.compile || o.print || o.lint);
     o.print = !!(o.print || (o.eval || o.stdio && o.compile));
-    return (sources = o.arguments);
+    return sources = o.arguments;
   };
   compileOptions = function(fileName) {
     return {
diff --git a/lib/grammar.js b/lib/grammar.js
index 4ddd29f0..4a11389b 100644
--- a/lib/grammar.js
+++ b/lib/grammar.js
@@ -11,7 +11,7 @@
     action = (match = unwrap.exec(action)) ? match[1] : "(" + action + "())";
     action = action.replace(/\bnew /g, '$&yy.');
     action = action.replace(/\b(?:Expressions\.wrap|extend)\b/g, 'yy.$&');
-    return [patternString, ("$$ = " + action + ";"), options];
+    return [patternString, "$$ = " + action + ";", options];
   };
   grammar = {
     Root: [
@@ -77,17 +77,17 @@
       })
     ],
     AssignObj: [
-      o("Identifier", function() {
+      o('Identifier', function() {
         return new Value($1);
-      }), o("AlphaNumeric"), o("ThisProperty"), o("Identifier   : Expression", function() {
+      }), o('AlphaNumeric'), o('ThisProperty'), o('Identifier   : Expression', function() {
         return new Assign(new Value($1), $3, 'object');
-      }), o("AlphaNumeric : Expression", function() {
+      }), o('AlphaNumeric : Expression', function() {
         return new Assign(new Value($1), $3, 'object');
-      }), o("Identifier   : INDENT Expression OUTDENT", function() {
+      }), o('Identifier   : INDENT Expression OUTDENT', function() {
         return new Assign(new Value($1), $4, 'object');
-      }), o("AlphaNumeric : INDENT Expression OUTDENT", function() {
+      }), o('AlphaNumeric : INDENT Expression OUTDENT', function() {
         return new Assign(new Value($1), $4, 'object');
-      }), o("Comment")
+      }), o('Comment')
     ],
     Return: [
       o("RETURN Expression", function() {
@@ -604,10 +604,10 @@
     alternatives = grammar[name];
     grammar[name] = (function() {
       _result = [];
-      for (_i = 0, _len = alternatives.length; _i < _len; _i++) {
+      for (_i = 0, _len = alternatives.length; _i < _len; ++_i) {
         alt = alternatives[_i];
         _result.push((function() {
-          for (_j = 0, _len2 = (_ref = alt[0].split(' ')).length; _j < _len2; _j++) {
+          for (_j = 0, _len2 = (_ref = alt[0].split(' ')).length; _j < _len2; ++_j) {
             token = _ref[_j];
             if (!grammar[token]) {
               tokens.push(token);
diff --git a/lib/helpers.js b/lib/helpers.js
index 1a716946..a971768f 100644
--- a/lib/helpers.js
+++ b/lib/helpers.js
@@ -11,7 +11,7 @@
   exports.compact = function(array) {
     var _i, _len, _result, item;
     _result = [];
-    for (_i = 0, _len = array.length; _i < _len; _i++) {
+    for (_i = 0, _len = array.length; _i < _len; ++_i) {
       item = array[_i];
       if (item) {
         _result.push(item);
@@ -41,7 +41,7 @@
   exports.flatten = flatten = function(array) {
     var _i, _len, element, flattened;
     flattened = [];
-    for (_i = 0, _len = array.length; _i < _len; _i++) {
+    for (_i = 0, _len = array.length; _i < _len; ++_i) {
       element = array[_i];
       if (element instanceof Array) {
         flattened = flattened.concat(flatten(element));
diff --git a/lib/lexer.js b/lib/lexer.js
index 80b5760c..3e41a3a2 100644
--- a/lib/lexer.js
+++ b/lib/lexer.js
@@ -59,7 +59,7 @@
       }
       forcedIdentifier = colon || this.tagAccessor();
       tag = 'IDENTIFIER';
-      if ((__indexOf.call(JS_KEYWORDS, id) >= 0) || !forcedIdentifier && (__indexOf.call(COFFEE_KEYWORDS, id) >= 0)) {
+      if (__indexOf.call(JS_KEYWORDS, id) >= 0 || !forcedIdentifier && __indexOf.call(COFFEE_KEYWORDS, id) >= 0) {
         tag = id.toUpperCase();
         if (tag === 'WHEN' && (_ref2 = this.tag(), __indexOf.call(LINE_BREAK, _ref2) >= 0)) {
           tag = 'LEADING_WHEN';
@@ -228,7 +228,7 @@
       tokens = [];
       for (_i = 0, _len = (_ref2 = this.interpolateString(body, {
         regex: true
-      })).length; _i < _len; _i++) {
+      })).length; _i < _len; ++_i) {
         _ref3 = _ref2[_i], tag = _ref3[0], value = _ref3[1];
         if (tag === 'TOKENS') {
           tokens.push.apply(tokens, value);
@@ -355,7 +355,7 @@
         if (!prev[1].reserved && (_ref2 = prev[1], __indexOf.call(JS_FORBIDDEN, _ref2) >= 0)) {
           this.assignmentError();
         }
-        if (((_ref3 = prev[1]) === '||' || _ref3 === '&&')) {
+        if ((_ref3 = prev[1]) === '||' || _ref3 === '&&') {
           prev[0] = 'COMPOUND_ASSIGN';
           prev[1] += '=';
           return true;
@@ -480,7 +480,7 @@
         if (levels.length && str.charAt(i) === '\\') {
           i += 1;
         } else {
-          for (_i = 0, _len = delimited.length; _i < _len; _i++) {
+          for (_i = 0, _len = delimited.length; _i < _len; ++_i) {
             pair = delimited[_i];
             open = pair[0], close = pair[1];
             if (levels.length && starts(str, close, i) && last(levels) === pair) {
@@ -556,7 +556,7 @@
       if (interpolated = tokens.length > 1) {
         this.token('(', '(');
       }
-      for (i = 0, _len = tokens.length; i < _len; i++) {
+      for (i = 0, _len = tokens.length; i < _len; ++i) {
         _ref3 = tokens[i], tag = _ref3[0], value = _ref3[1];
         if (i) {
           this.token('+', '+');
diff --git a/lib/nodes.js b/lib/nodes.js
index 92616bc4..891a7f88 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -52,13 +52,13 @@
         if (!this.isComplex()) {
           return [this, this];
         } else {
-          reference = new Literal(o.scope.freeVariable(((options != null) ? options.name : undefined) || 'ref'));
+          reference = new Literal(o.scope.freeVariable('ref'));
           compiled = new Assign(reference, this);
           return [compiled, reference];
         }
       }).call(this);
-      if (((options != null) ? options.precompile : undefined)) {
-        for (i = 0, _len = pair.length; i < _len; i++) {
+      if ((options != null) ? options.precompile : undefined) {
+        for (i = 0, _len = pair.length; i < _len; ++i) {
           node = pair[i];
           (pair[i] = node.compile(o));
         }
@@ -69,6 +69,16 @@
       this.parenthetical = true;
       return this.compile(o);
     };
+    Base.prototype.compileLoopReference = function(o, name) {
+      var src, tmp;
+      src = tmp = this.compile(o);
+      if (!(NUMBER.test(src) || IDENTIFIER.test(src) && o.scope.check(src, {
+        immediate: true
+      }))) {
+        src = "" + (tmp = o.scope.freeVariable(name)) + " = " + src;
+      }
+      return [src, tmp];
+    };
     Base.prototype.idt = function(tabs) {
       return (this.tab || '') + Array((tabs || 0) + 1).join(TAB);
     };
@@ -104,7 +114,7 @@
       idt || (idt = '');
       children = (function() {
         _result = [];
-        for (_i = 0, _len = (_ref2 = this.collectChildren()).length; _i < _len; _i++) {
+        for (_i = 0, _len = (_ref2 = this.collectChildren()).length; _i < _len; ++_i) {
           child = _ref2[_i];
           _result.push(child.toString(idt + TAB));
         }
@@ -118,10 +128,10 @@
       if (!this.children) {
         return;
       }
-      for (_i = 0, _len = (_ref2 = this.children).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.children).length; _i < _len; ++_i) {
         attr = _ref2[_i];
         if (this[attr]) {
-          for (_j = 0, _len2 = (_ref3 = flatten([this[attr]])).length; _j < _len2; _j++) {
+          for (_j = 0, _len2 = (_ref3 = flatten([this[attr]])).length; _j < _len2; ++_j) {
             child = _ref3[_j];
             if (func(child) === false) {
               return;
@@ -189,9 +199,9 @@
     };
     Expressions.prototype.makeReturn = function() {
       var end, idx;
-      end = this.expressions[(idx = this.expressions.length - 1)];
+      end = this.expressions[idx = this.expressions.length - 1];
       if (end instanceof Comment) {
-        end = this.expressions[(idx -= 1)];
+        end = this.expressions[idx -= 1];
       }
       if (end && !(end instanceof Return)) {
         this.expressions[idx] = end.makeReturn();
@@ -206,7 +216,7 @@
       var _i, _len, _ref2, _result, node;
       return (function() {
         _result = [];
-        for (_i = 0, _len = (_ref2 = this.expressions).length; _i < _len; _i++) {
+        for (_i = 0, _len = (_ref2 = this.expressions).length; _i < _len; ++_i) {
           node = _ref2[_i];
           _result.push(this.compileExpression(node, merge(o)));
         }
@@ -264,7 +274,7 @@
     };
     Literal.prototype.isStatement = function() {
       var _ref2;
-      return ((_ref2 = this.value) === 'break' || _ref2 === 'continue' || _ref2 === 'debugger');
+      return (_ref2 = this.value) === 'break' || _ref2 === 'continue' || _ref2 === 'debugger';
     };
     Literal.prototype.isPureStatement = Literal.prototype.isStatement;
     Literal.prototype.isComplex = NO;
@@ -302,7 +312,7 @@
     Return.prototype.makeReturn = THIS;
     Return.prototype.compile = function(o) {
       var _ref2, expr;
-      expr = (((_ref2 = this.expression) != null) ? _ref2.makeReturn() : undefined);
+      expr = ((_ref2 = this.expression) != null) ? _ref2.makeReturn() : undefined;
       if (expr && !(expr instanceof Return)) {
         return expr.compile(o);
       }
@@ -405,7 +415,7 @@
       if (props[0] instanceof Accessor && this.isSimpleNumber()) {
         code = "(" + code + ")";
       }
-      for (_i = 0, _len = props.length; _i < _len; _i++) {
+      for (_i = 0, _len = props.length; _i < _len; ++_i) {
         prop = props[_i];
         (code += prop.compile(o));
       }
@@ -417,7 +427,7 @@
         Array.prototype.push.apply(ifn.body.properties, this.properties);
         return ifn;
       }
-      for (i = 0, _len = (_ref2 = this.properties).length; i < _len; i++) {
+      for (i = 0, _len = (_ref2 = this.properties).length; i < _len; ++i) {
         prop = _ref2[i];
         if (prop.soakNode) {
           prop.soakNode = false;
@@ -532,7 +542,7 @@
           break;
         }
       }
-      for (_i = 0, _len = (_ref3 = list.reverse()).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref3 = list.reverse()).length; _i < _len; ++_i) {
         call = _ref3[_i];
         if (ifn) {
           if (call.variable instanceof Call) {
@@ -550,8 +560,8 @@
       if (ifn = this.unfoldSoak(o)) {
         return ifn.compile(o);
       }
-      (((_ref2 = this.variable) != null) ? _ref2.tags.front = this.tags.front : undefined);
-      for (_i = 0, _len = (_ref3 = this.args).length; _i < _len; _i++) {
+      ((_ref2 = this.variable) != null) ? _ref2.tags.front = this.tags.front : undefined;
+      for (_i = 0, _len = (_ref3 = this.args).length; _i < _len; ++_i) {
         arg = _ref3[_i];
         if (arg instanceof Splat) {
           return this.compileSplat(o);
@@ -559,7 +569,7 @@
       }
       args = (function() {
         _result = [];
-        for (_j = 0, _len2 = (_ref4 = this.args).length; _j < _len2; _j++) {
+        for (_j = 0, _len2 = (_ref4 = this.args).length; _j < _len2; ++_j) {
           arg = _ref4[_j];
           _result.push(arg.compileBare(o));
         }
@@ -574,7 +584,7 @@
       var base, fun, idt, name, ref, splatargs;
       splatargs = this.compileSplatArguments(o);
       if (this.isSuper) {
-        return ("" + (this.superReference(o)) + ".apply(this, " + splatargs + ")");
+        return "" + (this.superReference(o)) + ".apply(this, " + splatargs + ")";
       }
       if (!this.isNew) {
         base = Value.wrap(this.variable);
@@ -587,7 +597,7 @@
             fun += name.compile(o);
           }
         }
-        return ("" + fun + ".apply(" + ref + ", " + splatargs + ")");
+        return "" + fun + ".apply(" + ref + ", " + splatargs + ")";
       }
       idt = this.idt(1);
       return "(function(func, args, ctor) {\n" + idt + "ctor.prototype = func.prototype;\n" + idt + "var child = new ctor, result = func.apply(child, args);\n" + idt + "return typeof result === \"object\" ? result : child;\n" + (this.tab) + "})(" + (this.variable.compile(o)) + ", " + splatargs + ", function() {})";
@@ -668,7 +678,7 @@
       o.indent = this.idt(1);
       nonComments = (function() {
         _result = [];
-        for (_i = 0, _len = (_ref2 = this.properties).length; _i < _len; _i++) {
+        for (_i = 0, _len = (_ref2 = this.properties).length; _i < _len; ++_i) {
           prop = _ref2[_i];
           if (!(prop instanceof Comment)) {
             _result.push(prop);
@@ -679,7 +689,7 @@
       lastNoncom = last(nonComments);
       props = (function() {
         _result = [];
-        for (i = 0, _len = (_ref2 = this.properties).length; i < _len; i++) {
+        for (i = 0, _len = (_ref2 = this.properties).length; i < _len; ++i) {
           prop = _ref2[i];
           _result.push((function() {
             join = i === this.properties.length - 1 ? '' : prop === lastNoncom || prop instanceof Comment ? '\n' : ',\n';
@@ -700,7 +710,7 @@
     };
     ObjectLiteral.prototype.assigns = function(name) {
       var _i, _len, _ref2, prop;
-      for (_i = 0, _len = (_ref2 = this.properties).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.properties).length; _i < _len; ++_i) {
         prop = _ref2[_i];
         if (prop.assigns(name)) {
           return true;
@@ -727,14 +737,14 @@
     ArrayLiteral.prototype.compileNode = function(o) {
       var _i, _len, _len2, _ref2, _ref3, code, i, obj, objects;
       o.indent = this.idt(1);
-      for (_i = 0, _len = (_ref2 = this.objects).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.objects).length; _i < _len; ++_i) {
         obj = _ref2[_i];
         if (obj instanceof Splat) {
           return this.compileSplatLiteral(o);
         }
       }
       objects = [];
-      for (i = 0, _len2 = (_ref3 = this.objects).length; i < _len2; i++) {
+      for (i = 0, _len2 = (_ref3 = this.objects).length; i < _len2; ++i) {
         obj = _ref3[i];
         code = obj.compileBare(o);
         objects.push(obj instanceof Comment ? "\n" + code + "\n" + (o.indent) : i === this.objects.length - 1 ? code : code + ', ');
@@ -744,7 +754,7 @@
     };
     ArrayLiteral.prototype.assigns = function(name) {
       var _i, _len, _ref2, obj;
-      for (_i = 0, _len = (_ref2 = this.objects).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.objects).length; _i < _len; ++_i) {
         obj = _ref2[_i];
         if (obj.assigns(name)) {
           return true;
@@ -791,7 +801,7 @@
       } else {
         constructor = new Code([], new Expressions([new Return(new Literal('this'))]));
       }
-      for (_i = 0, _len = (_ref2 = this.properties).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.properties).length; _i < _len; ++_i) {
         prop = _ref2[_i];
         pvar = prop.variable, func = prop.value;
         if (pvar && pvar.base.value === 'constructor') {
@@ -873,14 +883,11 @@
         if (this.variable.isArray() || this.variable.isObject()) {
           return this.compilePatternMatch(o);
         }
-        if (this.variable.isSplice()) {
-          return this.compileSplice(o);
-        }
         if (ifn = If.unfoldSoak(o, this, 'variable')) {
           delete o.top;
           return ifn.compile(o);
         }
-        if (_ref2 = this.context, __indexOf.call(this.CONDITIONAL, _ref2) >= 0) {
+        if ((_ref2 = this.context, __indexOf.call(this.CONDITIONAL, _ref2) >= 0)) {
           return this.compileConditional(o);
         }
       }
@@ -893,14 +900,14 @@
       }
       val = this.value.compileBare(o);
       if (this.context === 'object') {
-        return ("" + name + ": " + val);
+        return "" + name + ": " + val;
       }
       if (!(isValue && (this.variable.hasProperties() || this.variable.namespaced))) {
         o.scope.find(name);
       }
       val = name + (" " + (this.context || '=') + " ") + val;
       if (stmt) {
-        return ("" + (this.tab) + val + ";");
+        return "" + (this.tab) + val + ";";
       }
       return top || this.parenthetical ? val : "(" + val + ")";
     };
@@ -935,7 +942,7 @@
         assigns.push("" + (ref = o.scope.freeVariable('ref')) + " = " + valVar);
         valVar = ref;
       }
-      for (i = 0, _len = objects.length; i < _len; i++) {
+      for (i = 0, _len = objects.length; i < _len; ++i) {
         obj = objects[i];
         idx = i;
         if (isObject) {
@@ -966,6 +973,11 @@
       code = assigns.join(', ');
       return top || this.parenthetical ? code : "(" + code + ")";
     };
+    Assign.prototype.compileConditional = function(o) {
+      var _ref2, left, rite;
+      _ref2 = this.variable.cacheReference(o), left = _ref2[0], rite = _ref2[1];
+      return new Op(this.context.slice(0, -1), left, new Assign(rite, this.value)).compile(o);
+    };
     Assign.prototype.assigns = function(name) {
       return this[this.context === 'object' ? 'value' : 'variable'].assigns(name);
     };
@@ -1001,7 +1013,7 @@
       delete o.globals;
       splat = undefined;
       params = [];
-      for (i = 0, _len = (_ref2 = this.params).length; i < _len; i++) {
+      for (i = 0, _len = (_ref2 = this.params).length; i < _len; ++i) {
         param = _ref2[i];
         if (splat) {
           if (param.attach) {
@@ -1029,7 +1041,7 @@
       o.scope.startLevel();
       params = (function() {
         _result = [];
-        for (_i = 0, _len2 = params.length; _i < _len2; _i++) {
+        for (_i = 0, _len2 = params.length; _i < _len2; ++_i) {
           param = params[_i];
           _result.push(param.compile(o));
         }
@@ -1038,7 +1050,7 @@
       if (!(empty || this.noReturn)) {
         this.body.makeReturn();
       }
-      for (_i = 0, _len2 = params.length; _i < _len2; _i++) {
+      for (_i = 0, _len2 = params.length; _i < _len2; ++_i) {
         param = params[_i];
         o.scope.parameter(param);
       }
@@ -1052,7 +1064,7 @@
       func = "" + open + (params.join(', ')) + ") {" + code + close;
       o.scope.endLevel();
       if (this.bound) {
-        return ("" + (utility('bind')) + "(" + func + ", " + (this.context) + ")");
+        return "" + (utility('bind')) + "(" + func + ", " + (this.context) + ")";
       }
       return this.tags.front ? "(" + func + ")" : func;
     };
@@ -1119,7 +1131,7 @@
         variadic = o.scope.freeVariable('result');
         o.scope.assign(variadic, len + ' >= ' + this.arglength);
         end = this.trailings.length ? ", " + len + " - " + (this.trailings.length) : undefined;
-        for (idx = 0, _len = (_ref2 = this.trailings).length; idx < _len; idx++) {
+        for (idx = 0, _len = (_ref2 = this.trailings).length; idx < _len; ++idx) {
           trailing = _ref2[idx];
           if (trailing.attach) {
             assign = trailing.assign;
@@ -1141,7 +1153,7 @@
       var _len, arg, args, code, end, i, prev;
       args = [];
       end = -1;
-      for (i = 0, _len = list.length; i < _len; i++) {
+      for (i = 0, _len = list.length; i < _len; ++i) {
         arg = list[i];
         code = arg.compile(o);
         prev = args[end];
@@ -1167,7 +1179,7 @@
       function While(condition, opts) {
         While.__super__.constructor.call(this);
         this.condition = ((opts != null) ? opts.invert : undefined) ? condition.invert() : condition;
-        this.guard = ((opts != null) ? opts.guard : undefined);
+        this.guard = (opts != null) ? opts.guard : undefined;
         return this;
       };
       return While;
@@ -1338,16 +1350,10 @@
       _ref2 = this.object.compileReference(o, {
         precompile: true
       }), sub = _ref2[0], ref = _ref2[1];
-      _ref3 = (function() {
-        if (this.negated) {
-          return [' !== ', ' && '];
-        } else {
-          return [' === ', ' || '];
-        }
-      }).call(this), cmp = _ref3[0], cnj = _ref3[1];
+      _ref3 = this.negated ? [' !== ', ' && '] : [' === ', ' || '], cmp = _ref3[0], cnj = _ref3[1];
       tests = (function() {
         _result = [];
-        for (i = 0, _len = (_ref4 = this.array.base.objects).length; i < _len; i++) {
+        for (i = 0, _len = (_ref4 = this.array.base.objects).length; i < _len; ++i) {
           item = _ref4[i];
           _result.push((i ? ref : sub) + cmp + item.compile(o));
         }
@@ -1363,7 +1369,7 @@
       }), {
         precompile: true
       }), sub = _ref2[0], ref = _ref2[1];
-      code = utility('indexOf') + (".call(" + (this.array.compile(o)) + ", " + ref + ") ")(+(this.negated ? '< 0' : '>= 0'));
+      code = utility('indexOf') + (".call(" + (this.array.compile(o)) + ", " + ref + ") ") + (this.negated ? '< 0' : '>= 0');
       return sub === ref ? code : "(" + sub + ", " + code + ")";
     };
     In.prototype.toString = function(idt) {
@@ -1518,26 +1524,16 @@
       return '';
     };
     For.prototype.compileNode = function(o) {
-      var _ref2, _ref3, _ref4, _ref5, _ref6, body, codeInBody, cond, forPart, guardPart, head, hvar, idt, incr, index, ivar, lastLine, lvar, name, namePart, pvar, ref, resultDef, resultRet, rvar, scope, sourcePart, step, svar, tail, top, tvar, varPart, vars;
-      if (this.step) {
-        o.top = true;
-        _ref2 = this.step.compileReference(o, {
-          precompile: true,
-          name: 'step'
-        }), step = _ref2[0], pvar = _ref2[1];
-      }
-      top = del(o, 'top') && !this.returns;
-      codeInBody = this.body.contains(function(node) {
-        return node instanceof Code;
-      });
+      var _ref2, _ref3, _ref4, _ref5, _ref6, body, cond, forPart, guardPart, idt, index, ivar, lvar, name, namePart, pvar, resultDef, resultRet, rvar, scope, sourcePart, step, svar, tail, top, tvar, varPart, vars;
       scope = o.scope;
-      name = !this.pattern && (((_ref3 = this.name) != null) ? _ref3.compile(o) : undefined);
-      index = (((_ref4 = this.index) != null) ? _ref4.compile(o) : undefined);
-      ivar = !index || codeInBody ? scope.freeVariable('i') : index;
+      top = del(o, 'top') && !this.returns;
+      name = !this.pattern && (((_ref2 = this.name) != null) ? _ref2.compile(o) : undefined);
+      index = ((_ref3 = this.index) != null) ? _ref3.compile(o) : undefined;
+      ivar = !index ? scope.freeVariable('i') : index;
       varPart = '';
       body = Expressions.wrap([this.body]);
       idt = this.idt(1);
-      if (name && !codeInBody) {
+      if (name) {
         scope.find(name, {
           immediate: true
         });
@@ -1547,46 +1543,24 @@
           immediate: true
         });
       }
-      if (!this.object) {
-        switch (+pvar) {
-          case 1:
-            incr = '++' + ivar;
-            break;
-          case -1:
-            incr = '--' + ivar;
-            break;
-          default:
-            incr = ivar + (pvar < 0 ? ' -= ' + pvar.slice(1) : ' += ' + pvar);
-        }
+      if (this.step) {
+        _ref4 = this.step.compileLoopReference(o, 'step'), step = _ref4[0], pvar = _ref4[1];
       }
       if (this.from) {
-        _ref5 = this.from.compileReference(o, {
-          precompile: true,
-          name: 'from'
-        }), head = _ref5[0], hvar = _ref5[1];
-        _ref6 = this.to.compileReference(o, {
-          precompile: true,
-          name: 'to'
-        }), tail = _ref6[0], tvar = _ref6[1];
-        vars = "" + ivar + " = " + head;
+        _ref5 = this.to.compileLoopReference(o, 'to'), tail = _ref5[0], tvar = _ref5[1];
+        vars = "" + ivar + " = " + (this.from.compile(o));
         if (tail !== tvar) {
           vars += ", " + tail;
         }
-        if (step !== pvar) {
-          vars += ", " + step;
-        }
-        cond = isNaN(step) ? "" + pvar + " < 0 ? " + ivar + " >= " + tvar + " : " + ivar + " <= " + tvar : "" + ivar + " " + (step < 0 ? '>=' : '<=') + " " + tvar;
-        forPart = "" + vars + "; " + cond + "; " + incr;
+        cond = +pvar ? "" + ivar + " " + (pvar < 0 ? '>' : '<') + "= " + tvar : "" + pvar + " < 0 ? " + ivar + " >= " + tvar + " : " + ivar + " <= " + tvar;
       } else {
-        svar = sourcePart = this.source.compile(o);
-        if ((name || !this.raw) && !(IDENTIFIER.test(svar) && scope.check(svar, {
-          immediate: true
-        }))) {
-          sourcePart = "" + (ref = scope.freeVariable('ref')) + " = " + svar;
-          if (!this.object) {
+        if (name || !this.raw) {
+          _ref6 = this.source.compileLoopReference(o, 'ref'), sourcePart = _ref6[0], svar = _ref6[1];
+          if (!(sourcePart === svar || this.object)) {
             sourcePart = "(" + sourcePart + ")";
           }
-          svar = ref;
+        } else {
+          sourcePart = svar = this.source.compile(o);
         }
         namePart = this.pattern ? new Assign(this.name, new Literal("" + svar + "[" + ivar + "]")).compile(merge(o, {
           top: true
@@ -1600,12 +1574,26 @@
             vars = "" + ivar + " = 0, " + lvar + " = " + sourcePart + ".length";
             cond = "" + ivar + " < " + lvar;
           }
-          if (step !== pvar) {
-            vars += ", " + step;
-          }
-          forPart = "" + vars + "; " + cond + "; " + incr;
         }
       }
+      if (this.object) {
+        forPart = "" + ivar + " in " + sourcePart;
+        guardPart = !this.raw && ("" + idt + "if (!" + (utility('hasProp')) + ".call(" + svar + ", " + ivar + ")) continue;\n");
+      } else {
+        if (step !== pvar) {
+          vars += ", " + step;
+        }
+        forPart = ("" + vars + "; " + cond + "; ") + (function() {
+          switch (+pvar) {
+            case 1:
+              return '++' + ivar;
+            case -1:
+              return '--' + ivar;
+            default:
+              return ivar + (pvar < 0 ? ' -= ' + pvar.slice(1) : ' += ' + pvar);
+          }
+        })();
+      }
       if (!top) {
         rvar = scope.freeVariable('result');
         resultDef = "" + (this.tab) + rvar + " = [];\n";
@@ -1615,40 +1603,8 @@
       if (this.guard) {
         body = Expressions.wrap([new If(this.guard, body)]);
       }
-      if (codeInBody) {
-        if (this.from) {
-          body.unshift(new Literal("var " + name + " = " + ivar));
-        }
-        if (namePart) {
-          body.unshift(new Literal("var " + namePart));
-        }
-        if (index) {
-          body.unshift(new Literal("var " + index + " = " + ivar));
-        }
-        lastLine = body.expressions.pop();
-        if (index) {
-          body.push(new Assign(new Literal(ivar), new Literal(index)));
-        }
-        if (nvar) {
-          body.push(new Assign(new Literal(nvar), new Literal(name)));
-        }
-        body.push(lastLine);
-        o.indent = this.idt(1);
-        body = Expressions.wrap([new Literal(body.compile(o))]);
-        if (index) {
-          body.push(new Assign(new Literal(index), new Literal(ivar)));
-        }
-        if (name) {
-          body.push(new Assign(new Literal(name), new Literal(nvar || ivar)));
-        }
-      } else {
-        if (namePart) {
-          varPart = "" + idt + namePart + ";\n";
-        }
-      }
-      if (this.object) {
-        forPart = "" + ivar + " in " + sourcePart;
-        guardPart = !this.raw && ("" + idt + "if (!" + (utility('hasProp')) + ".call(" + svar + ", " + ivar + ")) continue;\n");
+      if (namePart) {
+        varPart = "" + idt + namePart + ";\n";
       }
       return "" + (resultDef || '') + (this.tab) + "for (" + forPart + ") {\n" + (guardPart || '') + varPart + (body.compile(merge(o, {
         indent: idt,
@@ -1673,7 +1629,7 @@
     Switch.prototype.isStatement = YES;
     Switch.prototype.makeReturn = function() {
       var _i, _len, _ref2, pair;
-      for (_i = 0, _len = (_ref2 = this.cases).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.cases).length; _i < _len; ++_i) {
         pair = _ref2[_i];
         pair[1].makeReturn();
       }
@@ -1688,9 +1644,9 @@
       idt2 = o.indent = this.idt(2);
       o.top = true;
       code = "" + (this.tab) + "switch (" + ((((_ref2 = this.subject) != null) ? _ref2.compile(o) : undefined) || true) + ") {";
-      for (_i = 0, _len = (_ref3 = this.cases).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref3 = this.cases).length; _i < _len; ++_i) {
         _ref4 = _ref3[_i], conditions = _ref4[0], block = _ref4[1];
-        for (_j = 0, _len2 = (_ref5 = flatten([conditions])).length; _j < _len2; _j++) {
+        for (_j = 0, _len2 = (_ref5 = flatten([conditions])).length; _j < _len2; ++_j) {
           condition = _ref5[_j];
           if (!this.subject) {
             condition = condition.invert().invert();
@@ -1728,11 +1684,11 @@
     If.prototype.topSensitive = YES;
     If.prototype.bodyNode = function() {
       var _ref2;
-      return (((_ref2 = this.body) != null) ? _ref2.unwrap() : undefined);
+      return ((_ref2 = this.body) != null) ? _ref2.unwrap() : undefined;
     };
     If.prototype.elseBodyNode = function() {
       var _ref2;
-      return (((_ref2 = this.elseBody) != null) ? _ref2.unwrap() : undefined);
+      return ((_ref2 = this.elseBody) != null) ? _ref2.unwrap() : undefined;
     };
     If.prototype.addElse = function(elseBody) {
       if (this.isChain) {
@@ -1849,7 +1805,7 @@
   TAB = '  ';
   TRAILING_WHITESPACE = /[ \t]+$/gm;
   IDENTIFIER = /^[$A-Za-z_][$\w]*$/;
-  NUMBER = /^0x[\da-f]+$|^(?:\d+(\.\d+)?|\.\d+)(?:e[+-]?\d+)?$/i;
+  NUMBER = /^-?(?:0x[\da-f]+|(?:\d+(\.\d+)?|\.\d+)(?:e[+-]?\d+)?)$/i;
   SIMPLENUM = /^[+-]?\d+$/;
   IS_STRING = /^['"]/;
   utility = function(name) {
diff --git a/lib/optparse.js b/lib/optparse.js
index cd4e534e..d569528b 100755
--- a/lib/optparse.js
+++ b/lib/optparse.js
@@ -15,14 +15,14 @@
         arguments: []
       };
       args = normalizeArguments(args);
-      for (i = 0, _len = args.length; i < _len; i++) {
+      for (i = 0, _len = args.length; i < _len; ++i) {
         arg = args[i];
         isOption = !!(arg.match(LONG_FLAG) || arg.match(SHORT_FLAG));
         matchedRule = false;
-        for (_i = 0, _len2 = (_ref = this.rules).length; _i < _len2; _i++) {
+        for (_i = 0, _len2 = (_ref = this.rules).length; _i < _len2; ++_i) {
           rule = _ref[_i];
           if (rule.shortFlag === arg || rule.longFlag === arg) {
-            value = rule.hasArgument ? args[(i += 1)] : true;
+            value = rule.hasArgument ? args[i += 1] : true;
             options[rule.name] = rule.isList ? (options[rule.name] || []).concat(value) : value;
             matchedRule = true;
             break;
@@ -44,7 +44,7 @@
       if (this.banner) {
         lines.unshift("" + (this.banner) + "\n");
       }
-      for (_i = 0, _len = (_ref = this.rules).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref = this.rules).length; _i < _len; ++_i) {
         rule = _ref[_i];
         spaces = 15 - rule.longFlag.length;
         spaces = spaces > 0 ? Array(spaces + 1).join(' ') : '';
@@ -62,7 +62,7 @@
   buildRules = function(rules) {
     var _i, _len, _result, tuple;
     _result = [];
-    for (_i = 0, _len = rules.length; _i < _len; _i++) {
+    for (_i = 0, _len = rules.length; _i < _len; ++_i) {
       tuple = rules[_i];
       _result.push((function() {
         if (tuple.length < 3) {
@@ -91,10 +91,10 @@
     var _i, _j, _len, _len2, _ref, arg, l, match, result;
     args = args.slice(0);
     result = [];
-    for (_i = 0, _len = args.length; _i < _len; _i++) {
+    for (_i = 0, _len = args.length; _i < _len; ++_i) {
       arg = args[_i];
       if (match = arg.match(MULTI_FLAG)) {
-        for (_j = 0, _len2 = (_ref = match[1].split('')).length; _j < _len2; _j++) {
+        for (_j = 0, _len2 = (_ref = match[1].split('')).length; _j < _len2; ++_j) {
           l = _ref[_j];
           result.push('-' + l);
         }
diff --git a/lib/rewriter.js b/lib/rewriter.js
index a5b41df6..8b99f26c 100644
--- a/lib/rewriter.js
+++ b/lib/rewriter.js
@@ -71,7 +71,7 @@
         } else {
           tokens.splice(i, 0, after);
         }
-      } else if (prev && !((_ref = prev[0]) === 'TERMINATOR' || _ref === 'INDENT' || _ref === 'OUTDENT')) {
+      } else if (prev && ((_ref = prev[0]) !== 'TERMINATOR' && _ref !== 'INDENT' && _ref !== 'OUTDENT')) {
         if (((post != null) ? post[0] : undefined) === 'TERMINATOR' && ((after != null) ? after[0] : undefined) === 'OUTDENT') {
           tokens.splice.apply(tokens, [i + 2, 0].concat(tokens.splice(i, 2)));
           if (tokens[i + 2][0] !== 'TERMINATOR') {
@@ -87,7 +87,7 @@
   };
   exports.Rewriter.prototype.removeLeadingNewlines = function() {
     var _len, _ref, i, tag;
-    for (i = 0, _len = (_ref = this.tokens).length; i < _len; i++) {
+    for (i = 0, _len = (_ref = this.tokens).length; i < _len; ++i) {
       tag = _ref[i][0];
       if (tag !== 'TERMINATOR') {
         break;
@@ -112,7 +112,7 @@
       return ((_ref = token[0]) === ')' || _ref === 'CALL_END') || token[0] === 'OUTDENT' && this.tag(i - 1) === ')';
     };
     action = function(token, i) {
-      return (this.tokens[token[0] === 'OUTDENT' ? i - 1 : i][0] = 'CALL_END');
+      return this.tokens[token[0] === 'OUTDENT' ? i - 1 : i][0] = 'CALL_END';
     };
     return this.scanTokens(function(token, i) {
       if (token[0] === 'CALL_START') {
@@ -125,10 +125,10 @@
     var action, condition;
     condition = function(token, i) {
       var _ref;
-      return ((_ref = token[0]) === ']' || _ref === 'INDEX_END');
+      return (_ref = token[0]) === ']' || _ref === 'INDEX_END';
     };
     action = function(token, i) {
-      return (token[0] = 'INDEX_END');
+      return token[0] = 'INDEX_END';
     };
     return this.scanTokens(function(token, i) {
       if (token[0] === 'INDEX_START') {
@@ -142,12 +142,12 @@
     stack = [];
     condition = function(token, i) {
       var _ref, _ref2, one, tag, three, two;
-      if (('HERECOMMENT' === this.tag(i + 1) || 'HERECOMMENT' === this.tag(i - 1))) {
+      if ('HERECOMMENT' === this.tag(i + 1) || 'HERECOMMENT' === this.tag(i - 1)) {
         return false;
       }
       _ref = this.tokens.slice(i + 1, i + 4), one = _ref[0], two = _ref[1], three = _ref[2];
       tag = token[0];
-      return (tag === 'TERMINATOR' || tag === 'OUTDENT') && !(((two != null) ? two[0] : undefined) === ':' || ((one != null) ? one[0] : undefined) === '@' && ((three != null) ? three[0] : undefined) === ':') || tag === ',' && !((_ref2 = ((one != null) ? one[0] : undefined)) === 'IDENTIFIER' || _ref2 === 'NUMBER' || _ref2 === 'STRING' || _ref2 === '@' || _ref2 === 'TERMINATOR' || _ref2 === 'OUTDENT');
+      return (tag === 'TERMINATOR' || tag === 'OUTDENT') && !(((two != null) ? two[0] : undefined) === ':' || ((one != null) ? one[0] : undefined) === '@' && ((three != null) ? three[0] : undefined) === ':') || tag === ',' && ((_ref2 = (one != null) ? one[0] : undefined) !== 'IDENTIFIER' && _ref2 !== 'NUMBER' && _ref2 !== 'STRING' && _ref2 !== '@' && _ref2 !== 'TERMINATOR' && _ref2 !== 'OUTDENT');
     };
     action = function(token, i) {
       return this.tokens.splice(i, 0, ['}', '}', token[2]]);
@@ -201,7 +201,7 @@
       if (prev && !prev.spaced && tag === '?') {
         token.call = true;
       }
-      if (!(callObject || ((prev != null) ? prev.spaced : undefined) && (prev.call || (_ref2 = prev[0], __indexOf.call(IMPLICIT_FUNC, _ref2) >= 0)) && ((__indexOf.call(IMPLICIT_CALL, tag) >= 0) || !(token.spaced || token.newLine) && (__indexOf.call(IMPLICIT_UNSPACED_CALL, tag) >= 0)))) {
+      if (!(callObject || ((prev != null) ? prev.spaced : undefined) && (prev.call || (_ref2 = prev[0], __indexOf.call(IMPLICIT_FUNC, _ref2) >= 0)) && (__indexOf.call(IMPLICIT_CALL, tag) >= 0 || !(token.spaced || token.newLine) && __indexOf.call(IMPLICIT_UNSPACED_CALL, tag) >= 0))) {
         return 1;
       }
       tokens.splice(i, 0, ['CALL_START', '(', token[2]]);
@@ -211,13 +211,13 @@
           return true;
         }
         tag = token[0];
-        if ((tag === 'IF' || tag === 'ELSE' || tag === 'UNLESS' || tag === '->' || tag === '=>')) {
+        if (tag === 'IF' || tag === 'ELSE' || tag === 'UNLESS' || tag === '->' || tag === '=>') {
           seenSingle = true;
         }
         if (tag === 'PROPERTY_ACCESS' && this.tag(i - 1) === 'OUTDENT') {
           return true;
         }
-        return !token.generated && this.tag(i - 1) !== ',' && (__indexOf.call(IMPLICIT_END, tag) >= 0) && (tag !== 'INDENT' || (this.tag(i - 2) !== 'CLASS' && !(_ref3 = this.tag(i - 1), __indexOf.call(IMPLICIT_BLOCK, _ref3) >= 0) && !((post = this.tokens[i + 1]) && post.generated && post[0] === '{')));
+        return !token.generated && this.tag(i - 1) !== ',' && __indexOf.call(IMPLICIT_END, tag) >= 0 && (tag !== 'INDENT' || (this.tag(i - 2) !== 'CLASS' && (_ref3 = this.tag(i - 1), __indexOf.call(IMPLICIT_BLOCK, _ref3) < 0) && !((post = this.tokens[i + 1]) && post.generated && post[0] === '{')));
       }, action);
       if (prev[0] === '?') {
         prev[0] = 'FUNC_EXIST';
@@ -237,7 +237,7 @@
         tokens.splice.apply(tokens, [i + 2, 0].concat(this.indentation(token)));
         return 4;
       }
-      if ((__indexOf.call(SINGLE_LINERS, tag) >= 0) && this.tag(i + 1) !== 'INDENT' && !(tag === 'ELSE' && this.tag(i + 1) === 'IF')) {
+      if (__indexOf.call(SINGLE_LINERS, tag) >= 0 && this.tag(i + 1) !== 'INDENT' && !(tag === 'ELSE' && this.tag(i + 1) === 'IF')) {
         starter = tag;
         _ref2 = this.indentation(token), indent = _ref2[0], outdent = _ref2[1];
         if (starter === 'THEN') {
@@ -247,7 +247,7 @@
         tokens.splice(i + 1, 0, indent);
         condition = function(token, i) {
           var _ref3;
-          return token[1] !== ';' && (_ref3 = token[0], __indexOf.call(SINGLE_CLOSERS, _ref3) >= 0) && !(token[0] === 'ELSE' && !(starter === 'IF' || starter === 'THEN'));
+          return token[1] !== ';' && (_ref3 = token[0], __indexOf.call(SINGLE_CLOSERS, _ref3) >= 0) && !(token[0] === 'ELSE' && (starter !== 'IF' && starter !== 'THEN'));
         };
         action = function(token, i) {
           return this.tokens.splice(this.tag(i - 1) === ',' ? i - 1 : i, 0, outdent);
@@ -265,11 +265,11 @@
     var condition;
     condition = function(token, i) {
       var _ref;
-      return ((_ref = token[0]) === 'TERMINATOR' || _ref === 'INDENT');
+      return (_ref = token[0]) === 'TERMINATOR' || _ref === 'INDENT';
     };
     return this.scanTokens(function(token, i) {
       var _ref, original;
-      if (!((_ref = token[0]) === 'IF' || _ref === 'UNLESS')) {
+      if ((_ref = token[0]) !== 'IF' && _ref !== 'UNLESS') {
         return 1;
       }
       original = token;
@@ -286,7 +286,7 @@
     this.scanTokens(function(token, i) {
       var _i, _len, _ref, _ref2, close, open, tag;
       tag = token[0];
-      for (_i = 0, _len = (_ref = pairs).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref = pairs).length; _i < _len; ++_i) {
         _ref2 = _ref[_i], open = _ref2[0], close = _ref2[1];
         levels[open] |= 0;
         if (tag === open) {
@@ -330,10 +330,10 @@
         stack.push(token);
         return 1;
       }
-      if (!(__indexOf.call(EXPRESSION_END, tag) >= 0)) {
+      if (__indexOf.call(EXPRESSION_END, tag) < 0) {
         return 1;
       }
-      if (debt[(inv = INVERSES[tag])] > 0) {
+      if (debt[inv = INVERSES[tag]] > 0) {
         debt[inv] -= 1;
         tokens.splice(i, 1);
         return 0;
@@ -360,13 +360,13 @@
   };
   exports.Rewriter.prototype.tag = function(i) {
     var _ref;
-    return (((_ref = this.tokens[i]) != null) ? _ref[0] : undefined);
+    return ((_ref = this.tokens[i]) != null) ? _ref[0] : undefined;
   };
   BALANCED_PAIRS = [['(', ')'], ['[', ']'], ['{', '}'], ['INDENT', 'OUTDENT'], ['CALL_START', 'CALL_END'], ['PARAM_START', 'PARAM_END'], ['INDEX_START', 'INDEX_END']];
   INVERSES = {};
   EXPRESSION_START = [];
   EXPRESSION_END = [];
-  for (_i = 0, _len = BALANCED_PAIRS.length; _i < _len; _i++) {
+  for (_i = 0, _len = BALANCED_PAIRS.length; _i < _len; ++_i) {
     _ref = BALANCED_PAIRS[_i], left = _ref[0], rite = _ref[1];
     EXPRESSION_START.push(INVERSES[rite] = left);
     EXPRESSION_END.push(INVERSES[left] = rite);
diff --git a/lib/scope.js b/lib/scope.js
index 6fcef586..d19e2a3c 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -42,7 +42,7 @@
     };
     Scope.prototype.endLevel = function() {
       var _i, _len, _ref2, name;
-      for (_i = 0, _len = (_ref2 = this.garbage.pop()).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.garbage.pop()).length; _i < _len; ++_i) {
         name = _ref2[_i];
         if (this.type(name) === 'var') {
           this.add(name, 'reuse');
@@ -59,7 +59,7 @@
     };
     Scope.prototype.any = function(fn) {
       var _i, _len, _ref2, v;
-      for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; ++_i) {
         v = _ref2[_i];
         if (fn(v)) {
           return true;
@@ -83,7 +83,7 @@
     };
     Scope.prototype.type = function(name) {
       var _i, _len, _ref2, v;
-      for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; ++_i) {
         v = _ref2[_i];
         if (v.name === name) {
           return v.type;
@@ -98,7 +98,7 @@
         index++;
       }
       this.add(temp, 'var');
-      (((_ref2 = last(this.garbage)) != null) ? _ref2.push(temp) : undefined);
+      ((_ref2 = last(this.garbage)) != null) ? _ref2.push(temp) : undefined;
       return temp;
     };
     Scope.prototype.assign = function(name, value) {
@@ -110,7 +110,7 @@
     Scope.prototype.hasDeclarations = function(body) {
       return body === this.expressions && this.any(function(v) {
         var _ref2;
-        return ((_ref2 = v.type) === 'var' || _ref2 === 'reuse');
+        return (_ref2 = v.type) === 'var' || _ref2 === 'reuse';
       });
     };
     Scope.prototype.hasAssignments = function(body) {
@@ -122,9 +122,9 @@
       var _i, _len, _ref2, _ref3, _result, v;
       return (function() {
         _result = [];
-        for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; _i++) {
+        for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; ++_i) {
           v = _ref2[_i];
-          if (((_ref3 = v.type) === 'var' || _ref3 === 'reuse')) {
+          if ((_ref3 = v.type) === 'var' || _ref3 === 'reuse') {
             _result.push(v.name);
           }
         }
@@ -134,7 +134,7 @@
     Scope.prototype.assignedVariables = function() {
       var _i, _len, _ref2, _result, v;
       _result = [];
-      for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; _i++) {
+      for (_i = 0, _len = (_ref2 = this.variables).length; _i < _len; ++_i) {
         v = _ref2[_i];
         if (v.type.assigned) {
           _result.push("" + (v.name) + " = " + (v.type.value));
diff --git a/src/browser.coffee b/src/browser.coffee
index ddb7a0f1..05c6e018 100644
--- a/src/browser.coffee
+++ b/src/browser.coffee
@@ -33,7 +33,7 @@ runScripts = ->
       if script.src
         CoffeeScript.load script.src
       else
-        setTimeout -> CoffeeScript.run script.innerHTML
+        CoffeeScript.run script.innerHTML
   null
 if window.addEventListener
   addEventListener 'DOMContentLoaded', runScripts, no
diff --git a/src/grammar.coffee b/src/grammar.coffee
index 26a08242..d3573e4b 100644
--- a/src/grammar.coffee
+++ b/src/grammar.coffee
@@ -15,7 +15,7 @@
 # from our rules and saves it into `lib/parser.js`.
 
 # The only dependency is on the **Jison.Parser**.
-Parser = require('jison').Parser
+{Parser} = require 'jison'
 
 # Jison DSL
 # ---------
@@ -144,14 +144,14 @@ grammar =
   # Assignment when it happens within an object literal. The difference from
   # the ordinary **Assign** is that these allow numbers and strings as keys.
   AssignObj: [
-    o "Identifier",                             -> new Value $1
-    o "AlphaNumeric"
-    o "ThisProperty"
-    o "Identifier   : Expression",                -> new Assign new Value($1), $3, 'object'
-    o "AlphaNumeric : Expression",                -> new Assign new Value($1), $3, 'object'
-    o "Identifier   : INDENT Expression OUTDENT", -> new Assign new Value($1), $4, 'object'
-    o "AlphaNumeric : INDENT Expression OUTDENT", -> new Assign new Value($1), $4, 'object'
-    o "Comment"
+    o 'Identifier',                               -> new Value $1
+    o 'AlphaNumeric'
+    o 'ThisProperty'
+    o 'Identifier   : Expression',                -> new Assign new Value($1), $3, 'object'
+    o 'AlphaNumeric : Expression',                -> new Assign new Value($1), $3, 'object'
+    o 'Identifier   : INDENT Expression OUTDENT', -> new Assign new Value($1), $4, 'object'
+    o 'AlphaNumeric : INDENT Expression OUTDENT', -> new Assign new Value($1), $4, 'object'
+    o 'Comment'
   ]
 
   # A return statement from a function body.
diff --git a/src/nodes.coffee b/src/nodes.coffee
index 8b1c4ac6..940f8f6e 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -64,7 +64,7 @@ exports.Base = class Base
     pair = unless @isComplex()
       [this, this]
     else
-      reference = new Literal o.scope.freeVariable options?.name or 'ref'
+      reference = new Literal o.scope.freeVariable 'ref'
       compiled  = new Assign reference, this
       [compiled, reference]
     (pair[i] = node.compile o) for node, i in pair if options?.precompile
@@ -75,6 +75,14 @@ exports.Base = class Base
     @parenthetical = on
     @compile o
 
+  # Compile to a source/variable pair suitable for looping.
+  compileLoopReference: (o, name) ->
+    src = tmp = @compile o
+    unless NUMBER.test(src) or
+           IDENTIFIER.test(src) and o.scope.check(src, immediate: on)
+      src = "#{ tmp = o.scope.freeVariable name } = #{src}"
+    [src, tmp]
+
   # Convenience method to grab the current indentation level, plus tabbing in.
   idt: (tabs) ->
     (@tab or '') + Array((tabs or 0) + 1).join TAB
@@ -767,7 +775,6 @@ exports.Assign = class Assign extends Base
   compileNode: (o) ->
     if isValue = @variable instanceof Value
       return @compilePatternMatch(o) if @variable.isArray() or @variable.isObject()
-      return @compileSplice(o) if @variable.isSplice()
       if ifn = If.unfoldSoak o, this, 'variable'
         delete o.top
         return ifn.compile o
@@ -837,6 +844,13 @@ exports.Assign = class Assign extends Base
     code = assigns.join ', '
     if top or @parenthetical then code else "(#{code})"
 
+  # When compiling a conditional assignment, take care to ensure that the
+  # operands are only evaluated once, even though we have to reference them
+  # more than once.
+  compileConditional: (o) ->
+    [left, rite] = @variable.cacheReference o
+    return new Op(@context.slice(0, -1), left, new Assign(rite, @value)).compile o
+
   assigns: (name) ->
     @[if @context is 'object' then 'value' else 'variable'].assigns name
 
@@ -1291,7 +1305,7 @@ exports.For = class For extends Base
       throw SyntaxError 'index cannot be a pattern matching expression'
     super()
     extend this, head
-    @step or= new Literal 1 unless @object
+    @step  or= new Literal 1 unless @object
     @pattern = @name instanceof Value
     throw SyntaxError 'cannot pattern match a range loop' if @range and @pattern
     @returns = false
@@ -1310,42 +1324,31 @@ exports.For = class For extends Base
   # comprehensions. Some of the generated code can be shared in common, and
   # some cannot.
   compileNode: (o) ->
-    if @step
-      o.top = on
-      [step, pvar] = @step.compileReference o, precompile: on, name: 'step'
-    top        = del(o, 'top') and not @returns
-    codeInBody = @body.contains (node) -> node instanceof Code
-    scope      = o.scope
-    name       = not @pattern and @name?.compile o
-    index      = @index?.compile o
-    ivar       = if not index or codeInBody then scope.freeVariable 'i' else index
-    varPart    = ''
-    body       = Expressions.wrap [@body]
-    idt        = @idt 1
-    scope.find(name,  immediate: yes) if name and not codeInBody
+    {scope} = o
+    top     = del(o, 'top') and not @returns
+    name    = not @pattern and @name?.compile o
+    index   = @index?.compile o
+    ivar    = if not index then scope.freeVariable 'i' else index
+    varPart = ''
+    body    = Expressions.wrap [@body]
+    idt     = @idt 1
+    scope.find(name,  immediate: yes) if name
     scope.find(index, immediate: yes) if index
-    unless @object then switch +pvar
-      when  1 then incr = '++' + ivar
-      when -1 then incr = '--' + ivar
-      else incr = ivar + if pvar < 0 then ' -= ' + pvar.slice 1 else ' += ' + pvar
+    [step, pvar] = @step.compileLoopReference o, 'step' if @step
     if @from
-      [head, hvar] = @from.compileReference o, precompile: on, name: 'from'
-      [tail, tvar] = @to  .compileReference o, precompile: on, name: 'to'
-      vars  = "#{ivar} = #{head}"
+      [tail, tvar] = @to.compileLoopReference o, 'to'
+      vars  = "#{ivar} = #{ @from.compile o }"
       vars += ", #{tail}" if tail isnt tvar
-      vars += ", #{step}" if step isnt pvar
-      cond  = if isNaN step
-        "#{pvar} < 0 ? #{ivar} >= #{tvar} : #{ivar} <= #{tvar}"
+      cond = if +pvar
+        "#{ivar} #{ if pvar < 0 then '>' else '<' }= #{tvar}"
       else
-        "#{ivar} #{ if step < 0 then '>=' else '<=' } #{tvar}"
-      forPart = "#{vars}; #{cond}; #{incr}"
+        "#{pvar} < 0 ? #{ivar} >= #{tvar} : #{ivar} <= #{tvar}"
     else
-      svar = sourcePart = @source.compile o
-      if (name or not @raw) and
-         not (IDENTIFIER.test(svar) and scope.check svar, immediate: on)
-        sourcePart = "#{ ref = scope.freeVariable 'ref' } = #{svar}"
-        sourcePart = "(#{sourcePart})" unless @object
-        svar = ref
+      if name or not @raw
+        [sourcePart, svar] = @source.compileLoopReference o, 'ref'
+        sourcePart = "(#{sourcePart})" unless sourcePart is svar or @object
+      else
+        sourcePart = svar = @source.compile o
       namePart = if @pattern
         new Assign(@name, new Literal "#{svar}[#{ivar}]").compile merge o, top: on
       else if name
@@ -1358,35 +1361,26 @@ exports.For = class For extends Base
           lvar = scope.freeVariable 'len'
           vars = "#{ivar} = 0, #{lvar} = #{sourcePart}.length"
           cond = "#{ivar} < #{lvar}"
-        vars  += ", #{step}" if step isnt pvar
-        forPart = "#{vars}; #{cond}; #{incr}"
+    if @object
+      forPart   = "#{ivar} in #{sourcePart}"
+      guardPart = not @raw and
+        "#{idt}if (!#{ utility 'hasProp' }.call(#{svar}, #{ivar})) continue;\n"
+    else
+      vars += ", #{step}" if step isnt pvar
+      forPart = "#{vars}; #{cond}; " + switch +pvar
+        when  1 then '++' + ivar
+        when -1 then '--' + ivar
+        else ivar + if pvar < 0 then ' -= ' + pvar.slice 1 else ' += ' + pvar
     unless top
       rvar      = scope.freeVariable 'result'
       resultDef = "#{@tab}#{rvar} = [];\n"
       resultRet = @compileReturnValue rvar, o
       body      = Push.wrap rvar, body
     body = Expressions.wrap [new If @guard, body] if @guard
-    if codeInBody
-      body.unshift new Literal "var #{name} = #{ivar}"  if @from
-      body.unshift new Literal "var #{namePart}"        if namePart
-      body.unshift new Literal "var #{index} = #{ivar}" if index
-      lastLine    = body.expressions.pop()
-      body.push     new Assign new Literal(ivar), new Literal index if index
-      body.push     new Assign new Literal(nvar), new Literal name if nvar
-      body.push     lastLine
-      o.indent    = @idt 1
-      body        = Expressions.wrap [new Literal body.compile o]
-      body.push     new Assign new Literal(index), new Literal ivar if index
-      body.push     new Assign new Literal(name ), new Literal nvar or ivar if name
-    else
-      varPart = "#{idt}#{namePart};\n" if namePart
-    if @object
-      forPart   = "#{ivar} in #{sourcePart}"
-      guardPart = not @raw and
-        "#{idt}if (!#{ utility 'hasProp' }.call(#{svar}, #{ivar})) continue;\n" 
+    varPart = "#{idt}#{namePart};\n" if namePart
     """
     #{ resultDef or '' }#{@tab}for (#{forPart}) {
-    #{ guardPart or '' }#{varPart}#{ body.compile merge o, indent: idt, top: true }
+    #{ guardPart or '' }#{varPart}#{ body.compile merge o, indent: idt, top: on }
     #{@tab}}#{ resultRet or '' }
     """
 
@@ -1596,7 +1590,7 @@ TAB = '  '
 TRAILING_WHITESPACE = /[ \t]+$/gm
 
 IDENTIFIER = /^[$A-Za-z_][$\w]*$/
-NUMBER     = /^0x[\da-f]+$|^(?:\d+(\.\d+)?|\.\d+)(?:e[+-]?\d+)?$/i
+NUMBER     = /// ^ -? (?: 0x[\da-f]+ | (?:\d+(\.\d+)?|\.\d+)(?:e[+-]?\d+)? ) $ ///i
 SIMPLENUM  = /^[+-]?\d+$/
 
 # Is a literal value a string?
diff --git a/test/test_comprehensions.coffee b/test/test_comprehensions.coffee
index 0c7c7e4c..cebe40d7 100644
--- a/test/test_comprehensions.coffee
+++ b/test/test_comprehensions.coffee
@@ -45,55 +45,6 @@ ok 2 of evens
 # all/from/to aren't reserved.
 all = from = to = 1
 
-# Ensure that the closure wrapper preserves local variables.
-obj = {}
-
-for method in ['one', 'two', 'three']
-  obj[method] = ->
-    "I'm " + method
-
-ok obj.one()   is "I'm one"
-ok obj.two()   is "I'm two"
-ok obj.three() is "I'm three"
-
-i = 0
-for i in [1..3]
-  -> 'func'
-  break if false
-ok i is 3
-
-
-# Ensure that local variables are closed over for range comprehensions.
-funcs = for i from 1 to 3
-  -> -i
-
-ok (func() for func in funcs).join(' ') is '-1 -2 -3'
-ok i is 3
-
-
-# Ensure that closing over local variables doesn't break scoping laws.
-for i in [0]
-  count = 0
-  i = 50
-  ->
-ok count is 0
-ok i is 50
-
-for [a, b] in [[0, 1]] then ->
-ok a is 0
-ok b is 1
-
-
-# Even when referenced in the filter.
-list = ['one', 'two', 'three']
-
-methods = for num, i in list when num isnt 'two' and i isnt 1
-  -> num + ' ' + i
-
-ok methods.length is 2
-ok methods[0]() is 'one 0'
-ok methods[1]() is 'three 2'
-
 
 # Nested comprehensions.
 multiLiner =