+{-# OPTIONS_GHC -XNoImplicitPrelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : Data.IORef
module Data.IORef
(
- -- * IORefs
- IORef, -- abstract, instance of: Eq, Typeable
- newIORef, -- :: a -> IO (IORef a)
- readIORef, -- :: IORef a -> IO a
- writeIORef, -- :: IORef a -> a -> IO ()
- modifyIORef, -- :: IORef a -> (a -> a) -> IO ()
- atomicModifyIORef, -- :: IORef a -> (a -> (a,b)) -> IO b
+ -- * IORefs
+ IORef, -- abstract, instance of: Eq, Typeable
+ newIORef, -- :: a -> IO (IORef a)
+ readIORef, -- :: IORef a -> IO a
+ writeIORef, -- :: IORef a -> a -> IO ()
+ modifyIORef, -- :: IORef a -> (a -> a) -> IO ()
+ atomicModifyIORef, -- :: IORef a -> (a -> (a,b)) -> IO b
#if !defined(__PARALLEL_HASKELL__) && defined(__GLASGOW_HASKELL__)
- mkWeakIORef, -- :: IORef a -> IO () -> IO (Weak (IORef a))
+ mkWeakIORef, -- :: IORef a -> IO () -> IO (Weak (IORef a))
#endif
- ) where
-
-import Prelude -- Explicit dependency helps 'make depend' do the right thing
+ ) where
#ifdef __HUGS__
import Hugs.IORef
#endif
#ifdef __GLASGOW_HASKELL__
-import GHC.Base ( mkWeak#, atomicModifyMutVar# )
+import GHC.Base
import GHC.STRef
-import GHC.IOBase
+-- import GHC.IO
+import GHC.IORef hiding (atomicModifyIORef)
+import qualified GHC.IORef
#if !defined(__PARALLEL_HASKELL__)
import GHC.Weak
#endif
-- |Mutate the contents of an 'IORef'
modifyIORef :: IORef a -> (a -> a) -> IO ()
-modifyIORef ref f = writeIORef ref . f =<< readIORef ref
+modifyIORef ref f = readIORef ref >>= writeIORef ref . f
-- |Atomically modifies the contents of an 'IORef'.
--
atomicModifyIORef :: IORef a -> (a -> (a,b)) -> IO b
#if defined(__GLASGOW_HASKELL__)
-atomicModifyIORef (IORef (STRef r#)) f = IO $ \s -> atomicModifyMutVar# r# f s
+atomicModifyIORef = GHC.IORef.atomicModifyIORef
#elif defined(__HUGS__)
-atomicModifyIORef = plainModifyIORef -- Hugs has no preemption
+atomicModifyIORef = plainModifyIORef -- Hugs has no preemption
where plainModifyIORef r f = do
- a <- readIORef r
- case f a of (a',b) -> writeIORef r a' >> return b
+ a <- readIORef r
+ case f a of (a',b) -> writeIORef r a' >> return b
#elif defined(__NHC__)
atomicModifyIORef r f =
excludeFinalisers $ do