import idollars.dzn;

interface internal
{
  in void e(in foobar fb);

  behaviour
  {
    on e: {}
  }
}

component one
{
  provides idollars p;
  requires internal r;

  behaviour
  {
    on p.e(fb): r.e(fb);
  }
}

component two
{
  provides internal p;

  behaviour
  {
    on p.e(fb): {}
  }
}

component dollars
{
  provides idollars p;

  system
  {
    one o;
    two t;

    p <=> o.p;
    o.r <=> t.p;
  }
}