Use explicit language extensions & remove extension fields from base.cabal

[ghc-base.git] / Data / IORef.hs

diff --git a/Data/IORef.hs b/Data/IORef.hs
index 7a6ec7d..a6f29e7 100644 (file)
--- a/Data/IORef.hs
+++ b/Data/IORef.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP, NoImplicitPrelude, MagicHash, UnboxedTuples #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.IORef
@@ -14,29 +16,29 @@
 
 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
@@ -61,7 +63,7 @@ mkWeakIORef r@(IORef (STRef r#)) f = IO $ \s ->
 
 -- |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'.
@@ -76,13 +78,13 @@ modifyIORef ref f = writeIORef ref . f =<< readIORef ref
 --
 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