Proof of concept to extend objects and maintain protected data

FAO_Steve.js

// A simple class creation library.

// Inspired by base2 and Prototype
(function(){
  var initializing = false,
    // Determine if functions can be serialized
    fnTest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;
 
  // Create a new Class that inherits from this class
  Object.subClass = function(prop) {
    var _super = this.prototype;
   
    // Instantiate a base class (but only create the instance,
    // don't run the init constructor)
    initializing = true;
    var proto = new this();
    initializing = false;
   
    // Copy the properties over onto the new prototype
    for (var name in prop) {
      // Check if we're overwriting an existing function
      proto[name] = typeof prop[name] == "function" &&
        typeof _super[name] == "function" && fnTest.test(prop[name]) ?
        (function(name, fn){
          return function() {
            var tmp = this._super;
           
            // Add a new ._super() method that is the same method
            // but on the super-class
            this._super = _super[name];
           
            // The method only need to be bound temporarily, so we
            // remove it when we're done executing
            var ret = fn.apply(this, arguments);       
            this._super = tmp;
           
            return ret;
          };
        })(name, prop[name]) :
        prop[name];
    }
   
    // The dummy class constructor
    function Class() {
      // All construction is actually done in the init method
      if ( !initializing && this.init )
        this.init.apply(this, arguments);
    }
   
    // Populate our constructed prototype object
    Class.prototype = proto;
   
    // Enforce the constructor to be what we expect
    Class.constructor = Class;

    // And make this class extendable
    Class.subClass = arguments.callee;
   
    return Class;
  };
})();

function curry (fn /*, ... */)
{
	var aCurryArgs = Array.prototype.slice.call(arguments, 1);

	return function ( /* ... */ )
	{
		var aCalleeArgs = Array.prototype.slice.call(arguments, 0),
			aMergedArgs = aCurryArgs.concat(aCalleeArgs);

		return fn.apply(this, aMergedArgs);
	};
};

// #########################################################

var Sup = Object.subClass({
	echo: function(oProtected, sComment){
		alert('Sup:' + oProtected.secret + ' ' + sComment);
	}
});

var Sub = Sup.subClass({
	echo: function(oProtected, sComment){
		this._super(oProtected, sComment);
		alert('Sub:' + oProtected.secret + ' ' + sComment);
	}
});

function createSub(){
	var oInstance = new Sub(), oProtected = {
		secret: 'Hello World'
	};
	
	// bind the protected data with the original method
	for (var prop in oInstance) {
		if (typeof oInstance[prop] === 'function') {
			oInstance[prop] = SKY.utils.curry(oInstance[prop], oProtected);
		}
	}
	
	return oInstance;
}

createSub().echo('MOOOOOMIN');