X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Futils%2FMaybes.lhs;h=f1f859a5ea3d7e60fdd5232cd54c55e1acdb4c96;hb=1525a5819aa3a6eae8d8b05cfe348a2384da0c84;hp=3c9bd693e6d944f8bfe23f7c59f728bb60ee090b;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1;p=ghc-hetmet.git

diff --git a/compiler/utils/Maybes.lhs b/compiler/utils/Maybes.lhs
index 3c9bd69..f1f859a 100644
--- a/compiler/utils/Maybes.lhs
+++ b/compiler/utils/Maybes.lhs
@@ -8,7 +8,7 @@ module Maybes (
 	module Maybe,		-- Re-export all of Maybe
 
 	MaybeErr(..),	-- Instance of Monad
-	failME,
+	failME, isSuccess,
 
 	orElse, 
 	mapCatMaybes,
@@ -118,6 +118,10 @@ 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}