static java.util.Timer calcOnConceptChanges(int delay, final O runnable, final bool runOnFirstTime) {
  ret doEvery_daemon(delay, 0, new Runnable {
    long c = runOnFirstTime ? -1 : changeCount();
    new SingleThread thread;
    
    public void run() {
      long _c = changeCount();
      if (_c != c && !thread.running()) {
        c = _c;
        thread.go(runnable);
      }
    }
  });
}