// legacy
static <A extends Window> A onWindowClosing(A w, O r) {
  ret onWindowClosing(w, toRunnable(r));
}

static <A extends Window> A onWindowClosing(A w, Runnable r) {
  if (w != null) swing {
    w.addWindowListener(new WindowAdapter {
      public void windowClosing(WindowEvent e) {
        temp tempRememberListener(w, 'removeWindowListener, this);
        pcallF(r);
      }
    });
  }
  ret w;
}

static <A extends Window> A onWindowClosing(Runnable r, A w) {
  ret onWindowClosing(w, r);
}