-----------------------------------------------------------------------------
-- References for the IO monad:
--
-- This file contains (non-standard) hooks for an implementation of
-- mutable variables, or references, in O'Hugs.  These operations
-- are only available if the version of Hugs that you are using was
-- built with the IO_REFS flag set.
--
-- Suitable for use with O'Hugs.
-----------------------------------------------------------------------------

module IORef where

-- type IORef a       -- builtin type of IO references

primitive newIORef   :: a -> IO (IORef a)
primitive readIORef  :: IORef a -> IO a
primitive writeIORef :: IORef a -> a -> IO ()
primitive eqIORef    :: IORef a -> IORef a -> Bool

instance Eq (IORef a) where
    (==) = eqIORef

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