src/RMCA/Translator/SortMessage.hs

   1 -- The idea is that the stream of data coming from the MIDI input port
   2 -- will be sorted in three categories: note on events, controller
   3 -- events and other events. The latter will be transmitted as is
   4 -- through the whole systems.
   5
   6 module RMCA.Translator.SortMessage where
   7
   8 import qualified Data.Bifunctor          as BF
   9 import           Data.Function           (on)
  10 import           Data.List               (groupBy)
  11 import           Data.Maybe
  12 import           RMCA.Semantics
  13 import           RMCA.Translator.Message
  14 import           RMCA.Translator.Note
  15
  16 sortRawMessages :: [(Frames, RawMessage)]
  17                 -> ([(Frames,Message)], [(Frames,RawMessage)])
  18 sortRawMessages = sortRawMessages' ([],[])
  19   where sortRawMessages' r [] = r
  20         sortRawMessages' (m, rm) (x@(n,xm):xs)
  21           | isNothing nm = sortRawMessages' (m, x:rm) xs
  22           | otherwise = sortRawMessages' ((n,fromJust nm) :m, rm) xs
  23           where nm = fromRawMessage xm
  24
  25 -- Direct each message to a specific channel.
  26 -- /!\ To be modified.
  27 sortChannel :: [Message] -> [(Int,[Message])]
  28 sortChannel = map ((,) <$> (fst . head) <*> map snd)
  29               . groupBy ((==) `on` fst) . map sortChannel'
  30   where sortChannel' :: Message -> (Int, Message)
  31         sortChannel' m = let c = getChannel m in (c,m)
  32
  33 -- NoteOn messages are on the right, other Control messages are on the
  34 -- left. For now we throw away NoteOff messages.
  35 sortNotes :: [(Frames, Message)]
  36           -> ([(Frames,Message)], [(Frames,Message)])
  37 sortNotes = sortNotes' ([],[])
  38   where sortNotes' r [] = r
  39         sortNotes' (n, c) (x@(_,m):xs)
  40           | isNoteOn m = sortNotes' (x:n, c) xs
  41           | isNoteOff m = sortNotes' (n,c) xs
  42           | isControl m = sortNotes' (n,x:c) xs
  43           | otherwise = sortNotes' (n,c) xs
  44
  45 -- Note messages are converted to PlayHeads
  46 convertMessages :: [(Frames,Message)] -> [(Frames,Note)]
  47 convertMessages = map (BF.second messageToNote)