Control/Monad/ST.hs

{-# LANGUAGE Unsafe #-}

-----------------------------------------------------------------------------
-- |
-- Module : Control.Monad.ST
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : experimental
-- Portability : non-portable (requires universal quantification for runST)
--
-- This library provides support for /strict/ state threads, as
-- described in the PLDI \'94 paper by John Launchbury and Simon Peyton
-- Jones /Lazy Functional State Threads/.
--
-----------------------------------------------------------------------------

module Control.Monad.ST (
 -- * The 'ST' Monad
 ST, -- abstract, instance of Functor, Monad, Typeable.
 runST, -- :: (forall s. ST s a) -> a
 fixST, -- :: (a -> ST s a) -> ST s a

 -- * Converting 'ST' to 'IO'
 RealWorld, -- abstract
 stToIO, -- :: ST RealWorld a -> IO a

 -- * Unsafe Functions
 unsafeInterleaveST,
 unsafeIOToST,
 unsafeSTToIO
 ) where

import Control.Monad.ST.Safe
import qualified Control.Monad.ST.Unsafe as U

{-# DEPRECATED unsafeInterleaveST, unsafeIOToST, unsafeSTToIO
 "Please import from Control.Monad.ST.Unsafe instead; This will be removed in the next release"
 #-}

{-# INLINE unsafeInterleaveST #-}
unsafeInterleaveST :: ST s a -> ST s a
unsafeInterleaveST = U.unsafeInterleaveST

{-# INLINE unsafeIOToST #-}
unsafeIOToST :: IO a -> ST s a
unsafeIOToST = U.unsafeIOToST

{-# INLINE unsafeSTToIO #-}
unsafeSTToIO :: ST s a -> IO a
unsafeSTToIO = U.unsafeSTToIO