X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FSTRef.hs;h=3edfb871ae33310be20c2fe330e45b6b3438ef5d;hb=e9e2a5412bb7cda8d13a063ac403d9f18ac97380;hp=336a61fbd30aabfb79b2b2bb320f590cbbd5bea3;hpb=1819f73fc5bb82bf8e2a57905edfde81017d9167;p=ghc-base.git

diff --git a/Data/STRef.hs b/Data/STRef.hs
index 336a61f..3edfb87 100644
--- a/Data/STRef.hs
+++ b/Data/STRef.hs
@@ -24,10 +24,19 @@ module Data.STRef (
 import Prelude
 
 #ifdef __GLASGOW_HASKELL__
+import GHC.ST
 import GHC.STRef
 #endif
 
-import Data.Dynamic
+#ifdef __HUGS__
+import Hugs.ST
+#endif
+
+import Data.Typeable
 
-#include "Dynamic.h"
+#include "Typeable.h"
 INSTANCE_TYPEABLE2(STRef,stRefTc,"STRef")
+
+-- |Mutate the contents of an 'STRef'
+modifySTRef :: STRef s a -> (a -> a) -> ST s ()
+modifySTRef ref f = writeSTRef ref . f =<< readSTRef ref