content: sub main()
      screen = createObject("roSGScreen")
      port = createObject("roMessagePort")
      screen.setMessagePort(port)
  
      scene = screen.createScene("mainScene")
      screen.show()
  
      while(true)
          msg = wait(0, port)
          msgType = type(msg)
          if msgType = "roSGScreenEvent"
              if msg.isScreenClosed()
                  exit while
              end if
          end if
      end while
  end sub