// $Id: Map.java,v 1.2 1999/11/05 19:21:30 leavens Exp $

package lib;

public class Map implements Iterator {

    protected Function saved_proc;
    protected Iterator saved_seq;

    /*@ public invariant: saved_proc != null && saved_seq != null
      @*/

    public Map(Function proc, Iterator seq)
    //@ requires: proc != null && seq != null;
    {
        saved_proc = proc;
        saved_seq = seq;
    }

    public boolean hasMore() {
        return saved_seq.hasMore();
    }

    public void advance() {
        saved_seq.advance();
    }

    public Object getElement() {
        return saved_proc.value(saved_seq.getElement());
    }
}