Function.Typed: MultiMethod Helper

Function.Typed.js

/*
Script: Function.Typed.js
	Helper for multimethods.

Copyright and License:
	Copyrighted 2010, Mark Obcena. MIT-Style License

Credits:
	Inspired by "Multimethods in Python"
	[http://alexgaynor.net/2010/jun/26/multimethods-python/]

*/

(function(){

var register = function(types, name, method){
	if (method instanceof Function)
		types[name.replace(/\s/g, '')] = method;
};

Function.Typed = function(methods){
	var types = {};
	var fn = function(){
		var key = Array.prototype.slice.call(arguments).map(function(arg){
			return typeOf(arg);
		}).join(','), fn = types[key];

		if (fn) return fn.apply(this, arguments);
		else if (types['*']) return types['*'].apply(this, arguments);
		else throw new TypeError('No method defined for type('+key+')');
	}.extend({
		register: function(name, method){
			if (typeOf(name) == 'object'){
				for (var key in name) register(types, key, name[key]);
				return this;
			}
			register(types, name, method);
			return this;
		},
		unregister: function(name){
			delete types[name.replace(/\s/g, '')];
			return this;
		}
	});
	fn.register(methods);
	return fn;
};

})();