import * as Async from UnitJS.Async;

function Box(initValue) {
	this.value = initValue;
}

Box.prototype.get = function(f) {
	f(this.value);
};

Box.prototype.set = function(newValue) {
	return function(f) {
		this.value = newValue;
		f();
	}.bind(this);
};

Box.prototype.use = function(f) {
	return function(g) {
		f(this.value)(g);
	}.bind(this);
};

Box.prototype.update = function(modifier) {
	return function(f) {
		modifier(this.value)(function (newValue) {this.value = newValue; f()}.bind(this));
	}.bind(this);
};

return {
	make: make
};

function make(initValue) {
	var box = new Box(initValue);
	return {
		get: box.get.bind(box),
		set: box.set.bind(box),
		use: box.use.bind(box),
		update: box.update.bind(box),
	};
}