-- Copyright (c) 2009-2010, ERICSSON AB, Koen Claessen
-- All rights reserved.
--
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--
-- * Redistributions of source code must retain the above copyright notice,
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{-# OPTIONS_GHC -O0 #-}
-- |
-- A simple implementation of \"observable sharing\". See
--
-- * Koen Claessen, David Sands,
-- \"/Observable sharing for functional circuit description/\",
-- Asian Computing Science Conference, 1999.
--
-- for more details.
module Feldspar.Core.Ref
( Ref
, refId
, deref
, ref
) where
import Data.Unique
import System.IO.Unsafe
data Ref a = Ref
{ refId :: Unique
, deref :: a
}
instance Eq (Ref a) where
Ref x _ == Ref y _ = x == y
instance Ord (Ref a) where
Ref x _ `compare` Ref y _ = x `compare` y
ref :: a -> Ref a
ref x = unsafePerformIO $ do
u <- newUnique
return (Ref u x)