sclass Pair<A, B> is Comparable<Pair<A, B>> {
  settable A a;
  settable B b;

  *() {}
  *(A *a, B *b) {}
  
  public int hashCode() {
    ret hashCodeFor(a) + 2*hashCodeFor(b);
  }
  
  public bool equals(O o) {
    if (o == this) true;
    if (!(o instanceof Pair)) false;
    Pair t = (Pair) o;
    ret eq(a, t.a) && eq(b, t.b);
  }
  
  toString {
    ret "<" + a + ", " + b + ">";
  }
  
  public int compareTo(Pair<A, B> p) {
    if (p == null) ret 1;
    int i = ((Comparable<A>) a).compareTo(p.a);
    if (i != 0) ret i;
    ret ((Comparable<B>) b).compareTo(p.b);
  }
}

Began life as a copy of #1004216