让你在JavaScript的方法中调用Super

jQuery作者John Resig提出了他的继承方案，让人眼前一亮的是能够支持类似Super的关键字调用父类方法。
由于比较习惯YUI/EXT继承方式，同时也了解这种方式的不足，看到John的方案，很想跃然一试，
但见其代码之复杂，思路之繁复，恐怕不能兼效率之（ext中多达7~8层的继承），抱着FUD的心态，望诸君评论之。

   1. // Inspired by base2 and Prototype  
   2. (function(){  
   3.   var initializing = false, fnTest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;  
   4.   
   5.   // The base Class implementation (does nothing)  
   6.   this.Class = function(){};  
   7.    
   8.   // Create a new Class that inherits from this class  
   9.   Class.extend = function(prop) {  
  10.     var _super = this.prototype;  
  11.      
  12.     // Instantiate a base class (but only create the instance,  
  13.     // don't run the init constructor)  
  14.     initializing = true;  
  15.     var prototype = new this();  
  16.     initializing = false;  
  17.      
  18.     // Copy the properties over onto the new prototype  
  19.     for (var name in prop) {  
  20.       // Check if we're overwriting an existing function  
  21.       prototype[name] = typeof prop[name] == "function" &&  
  22.         typeof _super[name] == "function" && fnTest.test(prop[name]) ?  
  23.         (function(name, fn){  
  24.           return function() {  
  25.             var tmp = this._super;  
  26.              
  27.             // Add a new ._super() method that is the same method  
  28.             // but on the super-class  
  29.             this._super = _super[name];  
  30.              
  31.             // The method only need to be bound temporarily, so we  
  32.             // remove it when we're done executing  
  33.             var ret = fn.apply(this, arguments);         
  34.             this._super = tmp;  
  35.              
  36.             return ret;  
  37.           };  
  38.         })(name, prop[name]) :  
  39.         prop[name];  
  40.     }  
  41.      
  42.     // The dummy class constructor  
  43.     function Class() {  
  44.       // All construction is actually done in the init method  
  45.       if ( !initializing && this.init )  
  46.         this.init.apply(this, arguments);  
  47.     }  
  48.      
  49.     // Populate our constructed prototype object  
  50.     Class.prototype = prototype;  
  51.      
  52.     // Enforce the constructor to be what we expect  
  53.     Class.constructor = Class;  
  54.   
  55.     // And make this class extendable  
  56.     Class.extend = arguments.callee;  
  57.      
  58.     return Class;  
  59.   };  
  60. })();