content: sub main()
      screen = CreateObject("roSGScreen")
      m.port = CreateObject("roMessagePort")
      screen.setMessagePort(m.port)
      scene = screen.CreateScene("mainScene")
      screen.show()
  
      while(true)
        msg = wait(0, m.port)
        msgType = type(msg)
  
        if msgType = "roSGScreenEvent"
          if msg.isScreenClosed() then return
        end if
      end while
  end sub
  