interface ihello
{
  in void hello();
  out void world();

  behaviour
  {
    on hello: { world; }
  }
}

component hellooutevent
{
  provides ihello h;
  requires iworld w;

  behaviour
  {
    on h.hello(): {
      w.world();
      h.world();
    }
  }
}

interface iworld
{
  in void world();

  behaviour
  {
    on world: {}
  }
}