Small comment only

[ghc-hetmet.git] / compiler / utils / IOEnv.hs

diff --git a/compiler/utils/IOEnv.hs b/compiler/utils/IOEnv.hs
index c0277ae..728e55c 100644 (file)
--- a/compiler/utils/IOEnv.hs
+++ b/compiler/utils/IOEnv.hs
@@ -1,3 +1,10 @@
+{-# 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
+
 --
 -- (c) The University of Glasgow 2002-2006
 --
@@ -47,6 +54,9 @@ instance Monad (IOEnv m) where
   return = returnM
   fail s = failM       -- Ignore the string
 
+instance Functor (IOEnv m) where
+  fmap f (IOEnv m) = IOEnv (\ env -> fmap f (m env))
+
 returnM :: a -> IOEnv env a
 returnM a = IOEnv (\ env -> return a)