readWord8 :: ReadValue Word8
readWord8 = readIntegral f
  where f (U8LIT x) = Just x
        f _          = Nothing
readWord8 :: ReadValue Word8
readWord8 = readIntegral f
  where f (U8LIT x) = Just x
        f _          = Nothing
readWord8 = readIntegral f
  where f (U8LIT x) = Just x
        f _          = Nothing