Control/Monad/ST/Safe.hs

{-# LANGUAGE Trustworthy #-}

-----------------------------------------------------------------------------
-- |
-- Module : Control.Monad.ST.Safe
-- 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/.
--
-- Safe API Only.
--
-----------------------------------------------------------------------------

module Control.Monad.ST.Safe (
 -- * 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
 ) where

import Control.Monad.ST.Imp