sclass ManagedStringPool {
  replace Addr with int.
  
  ManagedIntObjects_v1 mem;
  
  *(ManagedIntObjects_v1 *mem) {}
  
  sclass Entry {
    Addr addr;
    int references;
    
    *(Addr *addr, int *references) {}
  }
  
  new Map<S, Entry> map;
  
  // stores a string (creates if necessary and registers a reference)
  Addr store(S s) {
    Entry e = map.get(s);
    if (e == null)
      e = new Entry(mem.newString(s), 0);
    e.references++;
    ret e.addr;
  }
  
  // just queries
  Addr peek(S s) {
    Entry e = map.get(s);
    ret e == null ? 0 : e.addr;
  }
  
  // remove a reference
  void unstore(S s) {
    Entry e = map.get(s);
    if (e == null) fail("ManagedStringPool user error");
    if (--e.references == 0)
      map.remove(s);
  }
}