Refactored build of executable and library.

1 files changed, 29 insertions, 0 deletions

diff --git a/lib/ControlMaybe.hs b/lib/ControlMaybe.hs
new file mode 100644
index 0000000..659dab7
--- /dev/null
+++ b/lib/ControlMaybe.hs
@@ -0,0 +1,29 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+module ControlMaybe where
+
+-- import GHC.IO.Exception (IOException(..))
+import Control.Exception as Exception (IOException(..),catch)
+
+
+withJust :: Monad m => Maybe x -> (x -> m ()) -> m ()
+withJust (Just x) f = f x
+withJust Nothing  f = return ()
+
+whenJust :: Monad m => m (Maybe x) -> (x -> m ()) -> m ()
+whenJust acn f = do
+    x <- acn
+    withJust x f
+
+
+catchIO_ :: IO a -> IO a -> IO a
+catchIO_ a h = Exception.catch a (\(_ :: IOException) -> h)
+
+catchIO :: IO a -> (IOException -> IO a)  -> IO a
+catchIO body handler = Exception.catch body handler
+
+handleIO_ :: IO a -> IO a -> IO a
+handleIO_ = flip catchIO_
+
+
+handleIO :: (IOException -> IO a) -> IO a -> IO a
+handleIO = flip catchIO