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|
----------------------------------------------------------------------
-- |
-- Module : (Module)
-- Maintainer : (Maintainer)
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date $
-- > CVS $Author $
-- > CVS $Revision $
--
-- (Description of the module)
-----------------------------------------------------------------------------
module SharedString (shareString) where
import Data.HashTable as H
import System.IO.Unsafe (unsafePerformIO)
{-# NOINLINE stringPool #-}
stringPool :: HashTable String String
stringPool = unsafePerformIO $ new (==) hashString
{-# NOINLINE shareString #-}
shareString :: String -> String
shareString s = unsafePerformIO $ do
mv <- H.lookup stringPool s
case mv of
Just s' -> return s'
Nothing -> do
H.insert stringPool s s
return s
|
