Merge pull request #1 from liamoc/patch-1

Fix deadlock

Author: yamadapc

src/Control/Memoization/Utils.hs

@@ -22,7 +22,9 @@ memoize action = do
  return $ \arg -> do
  m <- takeMVar mm
  case Map.lookup arg m of
- Just ret -> return ret
+ Just ret -> do
+ putMVar mm m 
+ return ret
  Nothing -> do
  ret <- action arg
  putMVar mm (Map.insert arg ret m)