Pony + Bindx, coming soon.

Example.hx

class Example
{
	static function main() 
	{
		var t = new Tumbler();
		
		t.onEnable << function() trace('enable');
		t.onDisable << function() trace('disable');
		
		t.enabled = true;
		t.enabled = false;
	}
	
}

Tumbler.hx

import bindx.IBindable;
import pony.events.Signal0;

class Tumbler implements IBindable
{
	@:bindable
	public var enabled:Bool;
	
	public var onEnable:Signal0<Void>;
	public var onDisable:Signal0<Void>;
	
	public function new() {
		onEnable = enabledChanged.sub(true);
		onDisable = enabledChanged.sub(false);
	}
}