diff --git a/CHANGELOG b/CHANGELOG
index 466bb4a..a16d7a7 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+* Performance improvements in Function methods (Samuel Lebeau, kangax, jddalton, Tobie Langel).
+
 *1.6.0.3* (September 29, 2008)
 
 * Add support for the Chrome browser in jstest.rb. (Andrew Dupont)
diff --git a/src/lang/function.js b/src/lang/function.js
index 6ce56fd..df2f737 100644
--- a/src/lang/function.js
+++ b/src/lang/function.js
@@ -1,57 +1,88 @@
-Object.extend(Function.prototype, {
-  argumentNames: function() {
+Object.extend(Function.prototype, (function() {
+  var slice = Array.prototype.slice;
+  
+  function update(array, args) {
+    var arrayLength = array.length, length = args.length;
+    while (length--) array[arrayLength + length] = args[length];
+    return array;
+  }
+  
+  function merge(array, args) {
+    array = slice.call(array, 0);
+    return update(array, args);
+  }
+  
+  function argumentNames() {
     var names = this.toString().match(/^[\s\(]*function[^(]*\(([^\)]*)\)/)[1]
       .replace(/\s+/g, '').split(',');
     return names.length == 1 && !names[0] ? [] : names;
-  },
-  
-  bind: function() {
-    if (arguments.length < 2 && Object.isUndefined(arguments[0])) return this;
-    var __method = this, args = $A(arguments), object = args.shift();
-    return function() {
-      return __method.apply(object, args.concat($A(arguments)));
-    }
-  },
-  
-  bindAsEventListener: function() {
-    var __method = this, args = $A(arguments), object = args.shift();
-    return function(event) {
-      return __method.apply(object, [event || window.event].concat(args));
-    }
-  },
-  
-  curry: function() {
-    if (!arguments.length) return this;
-    var __method = this, args = $A(arguments);
-    return function() {
-      return __method.apply(this, args.concat($A(arguments)));
-    }
-  },
+  }
 
-  delay: function() { 
-    var __method = this, args = $A(arguments), timeout = args.shift() * 1000; 
+  function bind(context) {
+    if (arguments.length < 2 && Object.isUndefined(arguments[0])) return this;
+    var __method = this, args = slice.call(arguments, 1);
+    return function() {
+      var a = merge(args, arguments);
+      return __method.apply(context, a);
+    }
+  }
+
+  function bindAsEventListener(context) {
+    var __method = this, args = slice.call(arguments, 1);
+    return function(event) {
+      var a = update([event || window.event], args);
+      return __method.apply(context, a);
+    }
+  }
+
+  function curry() {
+    if (!arguments.length) return this;
+    var __method = this, args = slice.call(arguments, 0);
+    return function() {
+      var a = merge(args, arguments);
+      return __method.apply(this, a);
+    }
+  }
+
+  function delay(timeout) { 
+    var __method = this, args = slice.call(arguments, 1);
+    timeout = timeout * 1000
     return window.setTimeout(function() {
       return __method.apply(__method, args);
     }, timeout);
-  },
-  
-  defer: function() {
-    var args = [0.01].concat($A(arguments));
+  }
+
+  function defer() {
+    var args = update([0.01], arguments);
     return this.delay.apply(this, args);
-  },
-  
-  wrap: function(wrapper) {
+  }
+
+  function wrap(wrapper) {
     var __method = this;
     return function() {
-      return wrapper.apply(this, [__method.bind(this)].concat($A(arguments))); 
+      var a = update([__method.bind(this)], arguments);
+      return wrapper.apply(this, a);
     }
-  },
-  
-  methodize: function() {
+  }
+
+  function methodize() {
     if (this._methodized) return this._methodized;
     var __method = this;
     return this._methodized = function() {
-      return __method.apply(null, [this].concat($A(arguments)));
+      var a = update([this], arguments);
+      return __method.apply(null, a);
     };
   }
-});
\ No newline at end of file
+  
+  return {
+    argumentNames:       argumentNames,
+    bind:                bind,
+    bindAsEventListener: bindAsEventListener,
+    curry:               curry,
+    delay:               delay,
+    defer:               defer,
+    wrap:                wrap,
+    methodize:           methodize
+  }
+})());
+