Hello all, here is a Code snipped from a Sound.ALSA.Sequencer example (much has been stripped and this code does not do anything). I just don't seem to get it. Can someone please walk me through it and possibly show ways to avoid the massive nesting. dtz = do SndSeq.withDefault SndSeq.Block $ \h -> do Client.setName (h :: SndSeq.T SndSeq.DuplexMode) "Haskell-Melody" Port.withSimple h "out" (Port.caps [Port.capRead, Port.capSubsRead, Port.capWrite]) (Port.types [Port.typeMidiGeneric, Port.typeApplication]) $ \p -> do Queue.with h $ \q -> do c <- Client.getId h let me = Addr.Cons c p conn <- parseDestArgs h me ["20:0"] Queue.control h q Event.QueueStart Nothing Queue.control h q (Event.QueueTempo (Event.Tempo 10000000)) Nothing return () -- Martin