sclass PairIC {
  S a;
  S b;

  *() {}
  *(S *a, S *b) {}
  
  public int hashCode() {
    ret hashCodeFor(a) + 2*hashCodeFor(b);
  }
  
  public bool equals(O o) {
    if (o == this) true;
    if (!(o instanceof PairIC)) false;
    PairIC t = cast o;
    ret eq(a, t.a) && eq(b, t.b);
  }
  
  toString {
    ret "<" + a + ", " + b + ">";
  }
}

Began life as a copy of #1004219