interface ihello
{
  in bool hello();

  behaviour
  {
    on hello: reply (true);
  }
}

component hello_bool
{
  provides ihello h;
  requires iworld w;

  behaviour
  {
    bool b = false;
    on h.hello():
      {
        b = w.world();
        reply (b);
      }
  }
}

interface iworld
{
  in bool world();

  behaviour
  {
    on world: reply (true);
  }
}