如何使用同一按键控制两个变量？(LUA)

例子：如果我按下M6按钮，光标会移动到X位置，再次按下M6按钮时光标会移动到Y位置，那么我应该如何进行这种交替操作？

local TOPX, TOPY, MIDX, MIDY

TOPX = 59305        -- 顶部X坐标
TOPY = 54527        -- 顶部Y坐标
MIDX = 61764        -- 中部X坐标
MIDY = 58683        -- 中部Y坐标

function OnEvent(event, arg)
        for n = 1,2
            do
            if      event == "MOUSE_BUTTON_RELEASED" and arg == 6 then
                            MoveMouseTo(MIDX, MIDY);
        for n = 2,4
            do
                if
                    event == "MOUSE_BUTTON_RELEASED" and arg == 6 then
                            MoveMouseTo(TOPX, TOPY);

end
end
end
end
end