interface ihello
{
  enum r {t,f};
  in r hello();

  behaviour
  {
    on hello: reply (r.f);
  }
}

component hello_tick
{
  provides ihello h;
  requires iworld w;

  behaviour
  {
    enum r {f,t};

    on h.hello():
      {
        ihello.r r = w.world();
        ihello.r t = ihello.r.f;
        ihello.r s = r;
        reply (r);
      }
  }
}

interface iworld
{
  in ihello.r world();

  behaviour
  {
    on world: reply (ihello.r.f);
  }
}