void->void pipeline MovingAverage {
  add IntSource();
  add Averager(10);
  add IntPrinter();
}
int->int filter Averager(int n) {
  work pop 1 push 1 peek n {
    int sum = 0;
    for (int i = 0; i < n; i++)
      sum += peek(i);
    push(sum/n);
    pop();
  }
}

void->int filter IntSource {
    int x;
    init { x = 0; }
    work push 1 {
	push(x);
	x++;
    }
}

int->void filter IntPrinter {
    work pop 1 { println(pop()); }
}