[project @ 2003-05-30 09:19:39 by simonpj]

[ghc-base.git] / GHC / IOBase.lhs

diff --git a/GHC/IOBase.lhs b/GHC/IOBase.lhs
index be7c9c2..d8e61d6 100644 (file)
--- a/GHC/IOBase.lhs
+++ b/GHC/IOBase.lhs
@@ -391,7 +391,11 @@ data BufferMode
 -- IORefs
 
 -- |A mutable variable in the 'IO' monad
-newtype IORef a = IORef (STRef RealWorld a) deriving Eq
+newtype IORef a = IORef (STRef RealWorld a)
+
+-- explicit instance because Haddock can't figure out a derived one
+instance Eq (IORef a) where
+  IORef x == IORef y = x == y
 
 -- |Build a new 'IORef'
 newIORef    :: a -> IO (IORef a)
@@ -406,6 +410,46 @@ writeIORef  :: IORef a -> a -> IO ()
 writeIORef (IORef var) v = stToIO (writeSTRef var v)
 
 -- ---------------------------------------------------------------------------
+-- | An 'IOArray' is a mutable, boxed, non-strict array in the 'IO' monad.  
+-- The type arguments are as follows:
+--
+--  * @i@: the index type of the array (should be an instance of 'Ix')
+--
+--  * @e@: the element type of the array.
+--
+-- 
+
+newtype IOArray i e = IOArray (STArray RealWorld i e)
+
+-- explicit instance because Haddock can't figure out a derived one
+instance Eq (IOArray i e) where
+  IOArray x == IOArray y = x == y
+
+-- |Build a new 'IOArray'
+newIOArray :: Ix i => (i,i) -> e -> IO (IOArray i e)
+{-# INLINE newIOArray #-}
+newIOArray lu init  = stToIO $ do {marr <- newSTArray lu init; return (IOArray marr)}
+
+-- | Read a value from an 'IOArray'
+unsafeReadIOArray  :: Ix i => IOArray i e -> Int -> IO e
+{-# INLINE unsafeReadIOArray #-}
+unsafeReadIOArray (IOArray marr) i = stToIO (unsafeReadSTArray marr i)
+
+-- | Write a new value into an 'IOArray'
+unsafeWriteIOArray :: Ix i => IOArray i e -> Int -> e -> IO ()
+{-# INLINE unsafeWriteIOArray #-}
+unsafeWriteIOArray (IOArray marr) i e = stToIO (unsafeWriteSTArray marr i e)
+
+-- | Read a value from an 'IOArray'
+readIOArray  :: Ix i => IOArray i e -> i -> IO e
+readIOArray (IOArray marr) i = stToIO (readSTArray marr i)
+
+-- | Write a new value into an 'IOArray'
+writeIOArray :: Ix i => IOArray i e -> i -> e -> IO ()
+writeIOArray (IOArray marr) i e = stToIO (writeSTArray marr i e)
+
+
+-- ---------------------------------------------------------------------------
 -- Show instance for Handles
 
 -- handle types are 'show'n when printing error msgs, so