readInt8 :: ReadValue Int8
readInt8 = readIntegral f
  where f (I8LIT x) = Just x
        f _          = Nothing
readInt8 :: ReadValue Int8
readInt8 = readIntegral f
  where f (I8LIT x) = Just x
        f _          = Nothing
readInt8 = readIntegral f
  where f (I8LIT x) = Just x
        f _          = Nothing