X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Futils%2FMaybes.lhs;h=c9924f7e4b32607bf6ae62ce82877153600b1c57;hb=1a7d1b77334529ca96ed4cbc03fcb5f55dc2de4a;hp=f1f859a5ea3d7e60fdd5232cd54c55e1acdb4c96;hpb=2763f56de2097a34176aa883dd4f0b3de1cb896c;p=ghc-hetmet.git

diff --git a/compiler/utils/Maybes.lhs b/compiler/utils/Maybes.lhs
index f1f859a..c9924f7 100644
--- a/compiler/utils/Maybes.lhs
+++ b/compiler/utils/Maybes.lhs
@@ -1,11 +1,18 @@
 %
+% (c) The University of Glasgow 2006
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-\section[Maybes]{The `Maybe' types and associated utility functions}
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module Maybes (
-	module Maybe,		-- Re-export all of Maybe
+	module Data.Maybe,	-- Re-export all of Maybe
 
 	MaybeErr(..),	-- Instance of Monad
 	failME, isSuccess,
@@ -17,13 +24,12 @@ module Maybes (
 	expectJust,
 	maybeToBool,
 
-	thenMaybe, seqMaybe, returnMaybe, failMaybe
+	thenMaybe, seqMaybe, returnMaybe, failMaybe, fmapMMaybe
     ) where
 
 #include "HsVersions.h"
 
-import Maybe
-
+import Data.Maybe
 
 infixr 4 `orElse`
 \end{code}
@@ -101,6 +107,11 @@ failMaybe = Nothing
 orElse :: Maybe a -> a -> a
 (Just x) `orElse` y = x
 Nothing  `orElse` y = y
+
+fmapMMaybe :: Monad m => (a -> m b) -> Maybe a -> m (Maybe b)
+fmapMMaybe f Nothing  = return Nothing
+fmapMMaybe f (Just x) = f x >>= \x' -> return (Just x')
+
 \end{code}