module default;
const N = 2..max;
global protocol Ring(role Worker[1..N]) {
  Init() from __self to __self;
  rec Loop {
    PreRing() from __self to __self;
    foreach (i:1..N-1) {
      Process(T) from Worker[i:1..N-1] to Worker[i+1];
      ProcessN(T) from Worker[N] to Worker[1];
    }
    PostRing() from __self to __self;
    continue Loop;
  }
  Finish() from __self to __self;
}