function overloading in JavaScript

overloading.js

//first some exmaples
//overload examples

var add = function(x,y){
    return x+y;
}

overload("add",function(x,y,z){
    return x+y+z;
});

overload("add",function(x,y,z,a){
    return x+y+z+a;
});

/* example output
add(2,3)
>5

add(1,2,3)
>6

add(1,2,3,4)
>10

*/


//experiement adding arity based function overloading to javascript
//to do
var overload = function (namespace,name,def){
    var loc = name + "_overloads";
    
    //function has not been overloaded yet (may or may not already exist)
    if(namespace[loc] == undefined) {
	namespace[loc] = [];
	
	//in case there was already a function name there
	if(namespace[name] != undefined){
	    var old_func = namespace[name];
	    namespace[loc][old_func.length] = old_func;
	    //in the next step the original function will be over written
	}
	namespace[name] = function () {
	    var args = Array.prototype.slice.call(arguments);
	    return(
		namespace[loc][arguments.length].apply(namespace,args)
	    );
	};
    }
    
    //always the case
    namespace[loc][def.length] = def;    

};


//and of course all good programs should build off themselves as much as possible
//so we're using 'overload' to overload 'overload' with a sane default
overload(this,"overload",function(name,def){
    overload(this,name,def);
});