X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Futils%2FMonadUtils.hs;h=733eda17005dbac5ba482493241ca368735915d1;hp=20646572df43aa916498d0c119cdcc7050823231;hb=5e5a08eb37f5513cecb47101a97fdaf09c4be040;hpb=2c8d42f32022f4950606d75d53e45a4c30d210df

diff --git a/compiler/utils/MonadUtils.hs b/compiler/utils/MonadUtils.hs
index 2064657..733eda1 100644
--- a/compiler/utils/MonadUtils.hs
+++ b/compiler/utils/MonadUtils.hs
@@ -19,6 +19,7 @@ module MonadUtils
         , mapMaybeM
         , anyM, allM
         , foldlM, foldrM
+        , maybeMapM
         ) where
 
 ----------------------------------------------------------------------------------------
@@ -149,3 +150,8 @@ foldlM = foldM
 foldrM        :: (Monad m) => (b -> a -> m a) -> a -> [b] -> m a
 foldrM _ z []     = return z
 foldrM k z (x:xs) = do { r <- foldrM k z xs; k x r }
+
+-- | Monadic version of fmap specialised for Maybe
+maybeMapM :: Monad m => (a -> m b) -> (Maybe a -> m (Maybe b))
+maybeMapM _ Nothing  = return Nothing
+maybeMapM m (Just x) = liftM Just $ m x