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remove conflicting import for nhc98
[haskell-directory.git]
/
Data
/
STRef.hs
diff --git
a/Data/STRef.hs
b/Data/STRef.hs
index
747d5ba
..
10853be
100644
(file)
--- a/
Data/STRef.hs
+++ b/
Data/STRef.hs
@@
-1,33
+1,41
@@
-----------------------------------------------------------------------------
-----------------------------------------------------------------------------
---
+-- |
-- Module : Data.STRef
-- Copyright : (c) The University of Glasgow 2001
-- Module : Data.STRef
-- Copyright : (c) The University of Glasgow 2001
--- License : BSD-style (see the file libraries/core/LICENSE)
+-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : experimental
--
-- Maintainer : libraries@haskell.org
-- Stability : experimental
--- Portability : non-portable (requires non-portable module ST)
---
--- $Id: STRef.hs,v 1.2 2001/07/03 11:37:50 simonmar Exp $
+-- Portability : non-portable (uses Control.Monad.ST)
--
--
--- Mutable references in the ST monad.
+-- Mutable references in the (strict) ST monad.
--
-----------------------------------------------------------------------------
module Data.STRef (
--
-----------------------------------------------------------------------------
module Data.STRef (
+ -- * STRefs
STRef, -- abstract, instance Eq
newSTRef, -- :: a -> ST s (STRef s a)
readSTRef, -- :: STRef s a -> ST s a
STRef, -- abstract, instance Eq
newSTRef, -- :: a -> ST s (STRef s a)
readSTRef, -- :: STRef s a -> ST s a
- writeSTRef -- :: STRef s a -> a -> ST s ()
+ writeSTRef, -- :: STRef s a -> a -> ST s ()
+ modifySTRef -- :: STRef s a -> (a -> a) -> ST s ()
) where
import Prelude
#ifdef __GLASGOW_HASKELL__
) where
import Prelude
#ifdef __GLASGOW_HASKELL__
+import GHC.ST
import GHC.STRef
#endif
import GHC.STRef
#endif
-import Data.Dynamic
+#ifdef __HUGS__
+import Hugs.ST
+import Data.Typeable
-#include "Dynamic.h"
+#include "Typeable.h"
INSTANCE_TYPEABLE2(STRef,stRefTc,"STRef")
INSTANCE_TYPEABLE2(STRef,stRefTc,"STRef")
+#endif
+
+-- |Mutate the contents of an 'STRef'
+modifySTRef :: STRef s a -> (a -> a) -> ST s ()
+modifySTRef ref f = writeSTRef ref . f =<< readSTRef ref