!7

cprint {
  class State extends ProbabilisticMachine2.State {
    Runnable continuation;

    public State makeDescendant() {
      ret prepareDescendant(new State);
      s.continuation = continuation;
      ret s;
    }
    
    void doneWithSubroutine {
      if (continuation == null) ret;
      State s = makeDescendant(new State);
      s.continuation = null;
      switchTo(s);
      continuation.run();
    }
    
    void step {
      doneWithSubroutine();
    }
  }
  
  start-thread {
    new ProbabilisticMachine2<State> pm;
    pm.addState(new State, r {
      print("Hello");
    });

    stepAllWithStats(pm);
  }
}