sclass PtSet extends java.util.AbstractSet<Pt> {
  final CompactLongSet set;
  
  *() { set = new CompactLongSet; }
  *(int size) { set = new CompactLongSet(size); }
  
  *(Iterable<Pt> l) {
    this();
    if (l != null) for (Pt p : l) add(p);
  }
  
  *(Cl<Pt> l) {
    this(l(l));
    if (l != null) for (Pt p : l) add(p);
  }
  
  public int size() { ret set.size(); }
  
  @Override
  public bool contains(O o) {
    ret contains(o/Pt);
  }
  
  public bool contains(Pt p) {
    ret set.contains(ptToLong(p));
  }
  
  public bool contains(int x, int y) {
    ret set.contains(ptToLong(x, y));
  }
  
  public bool add(Pt p) {
    ret set.add(ptToLong(p));
  }
  
  public bool add(int x, int y) {
    ret set.add(ptToLong(x, y));
  }
  
  public bool remove(Pt p) {
    ret set.remove(ptToLong(p));
  }
  
  public bool remove(int x, int y) {
    ret set.remove(ptToLong(x, y));
  }
  
  public void clear { set.clear(); }
  
  public Iterator<Pt> iterator() {
    RenamedLongIterator it = set.iterator();
    ret new ItIt<Pt> {
      public bool hasNext() {
        ret it.hasNext();
      }
      
      public Pt next() {
        ret ptFromLong(it.nextLong());
      }
      
      public void remove() {
        it.remove();
      }
    };
  }
}

Began life as a copy of #1033756