-----------------------------------------------------------------------------
module Data.IORef
- ( 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 ()
+ (
+ -- * 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 ()
#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
+#ifdef __HUGS__
+import Hugs.IORef
+#endif
+
#ifdef __GLASGOW_HASKELL__
import GHC.Base ( mkWeak# )
import GHC.STRef
import Data.Dynamic
#if defined(__GLASGOW_HASKELL__) && !defined(__PARALLEL_HASKELL__)
+-- |Make a 'Weak' pointer to an 'IORef'
mkWeakIORef :: IORef a -> IO () -> IO (Weak (IORef a))
mkWeakIORef r@(IORef (STRef r#)) f = IO $ \s ->
case mkWeak# r# r f s of (# s1, w #) -> (# s1, Weak w #)
#endif
-#if defined __HUGS__
-data IORef a -- mutable variables containing values of type a
-
-primitive newIORef "newRef" :: a -> IO (IORef a)
-primitive readIORef "getRef" :: IORef a -> IO a
-primitive writeIORef "setRef" :: IORef a -> a -> IO ()
-primitive eqIORef "eqRef" :: IORef a -> IORef a -> Bool
-
-instance Eq (IORef a) where
- (==) = eqIORef
-#endif /* __HUGS__ */
-
+-- |Mutate the contents of an 'IORef'
modifyIORef :: IORef a -> (a -> a) -> IO ()
modifyIORef ref f = writeIORef ref . f =<< readIORef ref