sclass MapI<A, B> extends ItIt<B> {
  IF1<A, B> f;
  Iterator<A> it;
  
  *(IF1<A, B> *f, Iterator<A> *it) {}
  
  public bool hasNext() {
    ret it.hasNext();
  }
  
  public B next() {
    ret f.get(it.next());
  }
}