store midi event history in a simple list

1 files changed, 14 insertions, 8 deletions

diff --git a/midi-dump.hs b/midi-dump.hs
index 0f714ed..a5a3d9c 100644
--- a/midi-dump.hs
+++ b/midi-dump.hs
@@ -2,26 +2,32 @@ import AlsaSeq
 import Control.Concurrent (threadDelay)
 import qualified Sound.ALSA.Exception as AlsaExc
 import qualified Data.Set as Set
+import qualified Haskore.Basic.Pitch as Pitch
+import qualified Sound.ALSA.Sequencer.Event as Event
 
 main = main' `AlsaExc.catch` handler
   where
   handler e = putStrLn $ "alsa_exception: " ++ AlsaExc.show e
 
+data State = State {
+  keysDown :: MidiPitchSet,
+  inputHistory :: [Maybe Event.T]
+}
+
 main' = withAlsaInit $ \h public private q publicAddr privateAddr -> do
   cmdlineAlsaConnect h public
 
   let
     forwardNOW = forwardNoteEvent h q publicAddr
-    go keysDown = do
-      keysDown' <- parseAlsaEvents h keysDown (\ev -> do forwardNOW ev; hook ev)
-      if (keysDown == keysDown') then
+    go state = do
+      (events, keysDown') <- parseAlsaEvents' h (keysDown state) forwardNOW
+      if ((keysDown state) == keysDown') then
         threadDelay 15000 -- 15ms.  Seems like a lot, but it sounds OK.  Cuts CPU down to 2%.
       else do
+        let newHistory = if (Set.null $ keysDown state) then Nothing:newEvents else newEvents
+            newEvents = map Just events
         printChordLn keysDown'
-      go keysDown'
+        go (state { keysDown = keysDown', inputHistory = newHistory ++ inputHistory state })
 
   putStrLn "Rock on!"
-  go Set.empty
-
-hook :: MidiHook
-hook ev = return ()
+  go (State Set.empty [])