-type MutArray a = IOArray Int32 a
-type HTArray a = MutArray a -- Array Int32 a
-newMutArray = newIOArray
-readHTArray arr i = readMutArray arr i -- return $! (unsafeAt arr (fromIntegral i))
-readMutArray :: MutArray a -> Int32 -> IO a
-readMutArray arr i = unsafeReadIOArray arr (fromIntegral i)