More refactoring of constraint simplification

[ghc-hetmet.git] / compiler / utils / Maybes.lhs

diff --git a/compiler/utils/Maybes.lhs b/compiler/utils/Maybes.lhs
index 3c9bd69..7d1fa4e 100644 (file)
--- a/compiler/utils/Maybes.lhs
+++ b/compiler/utils/Maybes.lhs
@@ -1,14 +1,14 @@
 %
+% (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}
 module Maybes (
-       module Maybe,           -- Re-export all of Maybe
+       module Data.Maybe,      -- Re-export all of Maybe
 
        MaybeErr(..),   -- Instance of Monad
-       failME,
+       failME, isSuccess,
 
        orElse, 
        mapCatMaybes,
@@ -22,8 +22,7 @@ module Maybes (
 
 #include "HsVersions.h"
 
-import Maybe
-
+import Data.Maybe
 
 infixr 4 `orElse`
 \end{code}
@@ -118,6 +117,10 @@ instance Monad (MaybeErr err) where
   Succeeded v >>= k = k v
   Failed e    >>= k = Failed e
 
+isSuccess :: MaybeErr err val -> Bool
+isSuccess (Succeeded {}) = True
+isSuccess (Failed {})    = False
+
 failME :: err -> MaybeErr err val
 failME e = Failed e
 \end{code}