timerF :: F (Maybe (Int, Int)) Tick data Tick = Tick instance Eq Tick instance Show Tick
timerFprovides an interface to the timers in the runtime system.
Just (interval,first)will start the timer. After
firstms, the timer will alarm, then, if
intervalis non-zero, the timer will alarm repeatedly with that interval.
If input is
Nothing, the timer will stop.
Tickis output when the timer alarms.