var Class = function(parent) {
	var klass = function() {
		this.init.apply(this, arguments);
	}
	
	// 继承
	if (parent) {
		var subclass = function() {};
		subclass.prototype = parent.prototype;
		klass.prototype = new subclass();
	}
	// klass.prototype.init = function() {}
	
	klass.fn = klass.prototype;
	klass.fn.parent = klass;
	
	// 上下文代理
	klass.proxy = function(callback) {
		var self = this;
		return (function() {
			return callback.apply(self, arguments);
		})
	}
	klass.fn.proxy = klass.proxy;
	
	// 类扩展
	klass.extend = function(obj) {
		var extended = obj.extended;
		for (var i in obj) {
			klass[i] = obj[i];
		}
		if (extended) {
			extended(klass);
		}
	}
	
	// 实例扩展
	klass.include = function(obj) {
		var included = obj.included;
		for (var i in obj) {
			klass.fn[i] = obj[i];
		}
		if (included) {
			included(klass);
		}
	}
	
	return klass;	
};


// example

var Person = new Class();
Person.prototype.init = function() {
	//code here
}
Person.extend({
	find: function() {},
	exists: function() {}
});

Person.include({
	save: function() {},
	destroy: function() {}
});

Person.find();
var p1 = new Person();
p1.save();