function on_click(ctx, evt) 
  print('on_click');
end

function application_init()
  local win = Window.create(NULL, 0, 0, 0, 0);
  ok = Button.create(win, 10, 5, 80, 30);
  ok:set_text(to_wstr("ok"));

  print(ok, getmetatable(ok));
  label = Label.create(win, 100, 5, 80, 30);
  label:set_text(to_wstr("text"));
  print(ok, getmetatable(ok));
  print(label, getmetatable(label));

  rid = ok:on(EventType.EVT_CLICK, function(evt) 
    print(ok, getmetatable(ok));
    print(evt, getmetatable(evt));
    local e = PointerEvent.cast(evt);
    print(ok, getmetatable(ok));
    print(e, getmetatable(e));
    print("on click:" .. tostring(e.x) .. " " .. tostring(e.y))
    ok:off(rid)
    return Ret.OK;
  end);

  print(tostring(rid))
end

application_init()