diff --git a/lib/carto/index.js b/lib/carto/index.js
index 326b591..64ed5b4 100644
--- a/lib/carto/index.js
+++ b/lib/carto/index.js
@@ -1,13 +1,13 @@
-var util = require('util');
-var fs = require('fs');
-var path = require('path');
+var util = require('util'),
+    fs = require('fs'),
+    path = require('path');
 
 function getVersion() {
-    if (parseInt(process.version.split('.')[1]) > 4) {
+    if (parseInt(process.version.split('.')[1], 10) > 4) {
         return require('../../package.json').version.split('.');
     } else {
         // older node
-        var package_json = JSON.parse(fs.readFileSync(path.join(__dirname,'../../package.json')))
+        var package_json = JSON.parse(fs.readFileSync(path.join(__dirname,'../../package.json')));
         return package_json.version.split('.');
     }
 }
@@ -90,4 +90,3 @@ function stylize(str, style) {
     return '\033[' + styles[style][0] + 'm' + str +
            '\033[' + styles[style][1] + 'm';
 }
-
diff --git a/lib/carto/parser.js b/lib/carto/parser.js
index 45f172a..6ab1390 100644
--- a/lib/carto/parser.js
+++ b/lib/carto/parser.js
@@ -204,7 +204,7 @@ carto.Parser = function Parser(env) {
     this.env.inputs = this.env.inputs || {};
 
     // The Parser
-    return parser = {
+    parser = {
 
         imports: imports,
         //
@@ -245,7 +245,8 @@ carto.Parser = function Parser(env) {
                     if (!inString && c === '/') {
                         cc = input.charAt(i + 1);
                         if (cc === '/' || cc === '*') {
-                            if (match = comment.exec(input)) {
+                            match = comment.exec(input);
+                            if (match) {
                                 if (match.index === i) {
                                     i += match[0].length - 1;
                                     chunk.push(match[0]);
@@ -383,7 +384,7 @@ carto.Parser = function Parser(env) {
                 while ((node = $(this.rule) || $(this.ruleset) ||
                                $(this.comment)) ||
                                $(/^[\s\n]+/) || (node = $(this.invalid))) {
-                    node && root.push(node);
+                    if (node) root.push(node);
                 }
                 return root;
             },
@@ -809,7 +810,6 @@ carto.Parser = function Parser(env) {
             // Expressions either represent mathematical operations,
             // or white-space delimited Entities.
             //
-            //     1px solid black
             //     @var * 2
             expression: function() {
                 var e, delim, entities = [], d;
@@ -827,5 +827,6 @@ carto.Parser = function Parser(env) {
             }
         }
     };
+    return parser;
 };
 
diff --git a/lib/carto/tree/color.js b/lib/carto/tree/color.js
index 24b94de..f0b5803 100644
--- a/lib/carto/tree/color.js
+++ b/lib/carto/tree/color.js
@@ -3,12 +3,10 @@
 // RGB Colors - #ff0014, #eee
 //
 tree.Color = function Color(rgb, a) {
-    //
     // The end goal here, is to parse the arguments
     // into an integer triplet, such as `128, 255, 0`
     //
     // This facilitates operations and conversions.
-    //
     if (Array.isArray(rgb)) {
         this.rgb = rgb;
     } else if (rgb.length == 6) {
@@ -25,7 +23,7 @@ tree.Color = function Color(rgb, a) {
 
 tree.Color.prototype = {
     is: 'color',
-    eval: function() { return this; },
+    'eval': function() { return this; },
 
     // If we have some transparency, the only way to represent it
     // is via `rgba`. Otherwise, we use the hex representation,
@@ -87,5 +85,4 @@ tree.Color.prototype = {
     }
 };
 
-
 })(require('../tree'));
diff --git a/lib/carto/tree/comment.js b/lib/carto/tree/comment.js
index f7e0d90..0338202 100644
--- a/lib/carto/tree/comment.js
+++ b/lib/carto/tree/comment.js
@@ -9,7 +9,7 @@ tree.Comment.prototype = {
     toString: function(env) {
         return '<!--' + this.value + '-->';
     },
-    eval: function() { return this; }
+    'eval': function() { return this; }
 };
 
 })(require('../tree'));
diff --git a/lib/carto/tree/dimension.js b/lib/carto/tree/dimension.js
index 4d061da..aa631da 100644
--- a/lib/carto/tree/dimension.js
+++ b/lib/carto/tree/dimension.js
@@ -11,7 +11,7 @@ tree.Dimension = function Dimension(value, unit, index) {
 
 tree.Dimension.prototype = {
     is: 'float',
-    eval: function (env) {
+    'eval': function (env) {
         if (this.unit && ['px', '%'].indexOf(this.unit) === -1) {
              env.error({
                 message: "Invalid unit: '" + this.unit + "'",
diff --git a/lib/carto/tree/filter.js b/lib/carto/tree/filter.js
index b02a49c..29d3c1d 100644
--- a/lib/carto/tree/filter.js
+++ b/lib/carto/tree/filter.js
@@ -39,10 +39,11 @@ var ops = {
 };
 
 tree.Filter.prototype.toXML = function(env) {
-    if (this.val.eval) this._val = this.val.eval(env);
-    if (this.key.eval) this._key = this.key.eval(env);
-    if (this._key) var key = this._key.toString(false);
-    if (this._val) var val = this._val.toString(this._val.is == 'string');
+    var val, key;
+    if (this.val['eval']) this._val = this.val['eval'](env);
+    if (this.key['eval']) this._key = this.key['eval'](env);
+    if (this._key) key = this._key.toString(false);
+    if (this._val) val = this._val.toString(this._val.is == 'string');
 
     if (
         (ops[this.op][1] == 'numeric' && isNaN(this.val)) ||
diff --git a/lib/carto/tree/layer.js b/lib/carto/tree/layer.js
index 1a9e676..f36cfcf 100644
--- a/lib/carto/tree/layer.js
+++ b/lib/carto/tree/layer.js
@@ -17,8 +17,8 @@ tree.Layer.prototype.toXML = function() {
     }
 
     var prop_string = '';
-    for (var i in this.properties) {
-        prop_string += '  ' + i + '="' + this.properties[i] + '"\n';
+    for (var prop in this.properties) {
+        prop_string += '  ' + prop + '="' + this.properties[prop] + '"\n';
     }
 
     return '<Layer' +
diff --git a/package.json b/package.json
index 4f5fe67..bc78e76 100644
--- a/package.json
+++ b/package.json
@@ -3,12 +3,10 @@
   "version": "0.9.4",
   "description": "Mapnik Stylesheet Compiler",
   "url": "https://github.com/mapbox/carto",
-  "repositories": [
-    {
-      "type": "git",
-      "url": "http://github.com/mapbox/carto.git"
-    }
-  ],
+  "repositories": [{
+    "type": "git",
+    "url": "http://github.com/mapbox/carto.git"
+  }],
   "author": {
     "name": "MapBox",
     "url": "http://mapbox.com/",
@@ -25,11 +23,9 @@
     "Konstantin Käfer",
     "Alexis Sellier <self@cloudhead.net>"
   ],
-  "licenses": [
-    {
+  "licenses": [{
       "type": "Apache"
-    }
-  ],
+  }],
   "bin": {
     "carto": "./bin/carto",
     "mml2json.js": "./bin/mml2json.js"