import qualified Sound.Alsa.Sequencer as ALSA
import Sound.Alsa.Sequencer (
   caps, cap_write, cap_subs_write, type_midi_generic,
   set_client_name, event_input,
   alsa_catch, exception_description,
   )

main :: IO ()
main = (do
  putStrLn "Starting."
  ALSA.with ALSA.default_seq_name ALSA.Block $ \h -> do
  ALSA.set_client_name (h :: ALSA.SndSeq ALSA.InputMode) "HS1"
  putStrLn "Created sequencer."
  ALSA.with_simple_port h "one"
     (caps [cap_write,cap_subs_write]) type_midi_generic $ \ _p1 -> do
  ALSA.with_simple_port h "two"
     (caps [cap_write,cap_subs_write]) type_midi_generic $ \ _p2 -> do
  putStrLn "Created ports."
  let loop = do putStrLn "waiting for an event:"
                e <- event_input h
                print e
                loop
  loop)
  `alsa_catch` \e -> putStrLn ("Problem: " ++ exception_description e)