import qualified Sound.Alsa.Sequencer as ALSA

import Control.Monad (when, )

main :: IO ()
main =
  ALSA.with ALSA.default_seq_name ALSA.Block $ \h -> do
  i <- ALSA.query_first_client (h :: ALSA.SndSeq ALSA.OutputMode)
  let loop = do putStrLn =<< ALSA.client_info_get_name i
                more <- ALSA.query_next_client h i
                when more loop
  loop