frp - How do I model time-based events in haskell? -

i'm building queue multiplexer in haskell, partly way learn , partly replacement dodgy shell scripts.

what periodically connect each queue (we're using rabbitmq) in turn measure queue depth. if main system consuming queue , queue has messages, nothing. if connected queue empty switch queue messages on it. if queues empty nothing. far good.

i need time-based switch, such if main application has been connected queue more 1 hour , queue empty, switch if other queues empty.

i'm thinking want emits events periodically trigger next cycle of behavior, 'check' events every minute , 'time-switch' events every hour.

is there idiomatic way model time-based events in haskell?

if understand correctly, sounds job control.concurrent. parts you'd use forkio spawn 1 of haskell's lightweight threads handle timing loop, , chan receive timing signals.

import control.concurrent import control.concurrent.chan import control.monad (forever)  main =   -- channel receive messages timing thread   chan <- newchan :: io (chan string)    -- spawn new thread send periodic signals   forkio $ forever $     writechan chan "hi!"     threaddelay $ 1 * 1000 * 1000 -- delay in microseconds    -- in main thread, listen messages chan.   forever $ readchan chan >>= print  

to expand on this, instead of writing strings chan make adt events, like:

data event = checkevent | switchevent deriving show 

and have listening thread different things based on event type.