make midi inputs and outputs optional

1 files changed, 13 insertions, 1 deletions

diff --git a/AlsaSeq.hs b/AlsaSeq.hs
index 8fb5bd2..22208bd 100644
--- a/AlsaSeq.hs
+++ b/AlsaSeq.hs
@@ -111,6 +111,17 @@ cmdlineAlsaConnect h public = do
   args <- getArgs
   case args of
 
+     ["0"] -> do
+       return ()
+
+     ["0", output] -> do
+        (Connect.createTo   h public =<< Addr.parse h output)
+        return ()
+
+     [input] -> do
+       (Connect.createFrom h public =<< Addr.parse h input)
+       return ()
+
      [input, output] -> do
         (Connect.createFrom h public =<< Addr.parse h input)
         (Connect.createTo   h public =<< Addr.parse h output)
@@ -118,7 +129,8 @@ cmdlineAlsaConnect h public = do
 
      _ -> do
         showAlsaPorts h
-        IO.hPutStrLn IO.stderr "need arguments: input-port output-port"
+        IO.hPutStrLn IO.stderr "need arguments: <input-port> [output-port]"
+        IO.hPutStrLn IO.stderr "  (use port 0 for no input)"
         Exit.exitFailure
 
 inputPendingLoop h b = do