[wxhaskell-users] reacting on ALSA events in a wxhaskell application

[Henning T. <le...@he...>]

I managed to write my first Haskell program with a GUI! It shows a window 
of sliders and when you move a slider it sends an according MIDI 
controller message via ALSA.

http://code.haskell.org/~thielema/alsa-gui/

Now I like to provide the reverse direction: If my program receives a MIDI 
controller event via ALSA, then it shall update the slider position. I can 
do this by using WX's timer events and check for incoming ALSA events in 
regular intervals. Is there also a way to wait for ALSA events as they 
come in, without a busy wait?