static int updateLoop_defaultInterval = 5000;
  
  static void updateLoop(int interval) {
    updateLoop_defaultInterval = interval;
    updateLoop();
  }
  
  static void updateLoop() {
    thread "update loop" {
      while (true) {
        try {
          update();
        } catch (Throwable e) {
          e.printStackTrace();
        }
        Integer interval = cast getOpt(getMainClass(), "updateInterval");
        sleep(interval == null || interval == 0 ? updateLoop_defaultInterval : interval);
      }
    }
  }

Optionally uses a variable called "updateInterval". Default is 5000 ms.