class MyActor{	F f;	MyActor inputs[];	MyActor outputs[];	int n;			#internal	void run()	{		f();		for o in outputs:			sendMsg(o, this)	}		##1	void addOutput(o)	{		outputs.append(o);	}		##2	void onFirstRun()	{		if inputs.empoty()			run()	}		##3	void onMsg(id)	{		n++;		if(n==inputs.size()) 			run()				}}def task(g, f, dependencies){	a= MyActor(f, dependencies);		// Tell dependencies add this actor to trigger list	for depend in dependencies:		depend.addOutput(a)			return a}t1 = task([](){hello});t2 = task([](){world}, t1);g.run()