unhexNibble :: Char -> Word8
unhexNibble ch =
  let (chDiff, intDiff) = diff ch
  in toEnum $ (fromEnum ch) - (fromEnum chDiff) + intDiff
unhexNibble :: Char -> Word8
unhexNibble ch =
  let (chDiff, intDiff) = diff ch
  in toEnum $ (fromEnum ch) - (fromEnum chDiff) + intDiff
unhexNibble ch =
  let (chDiff, intDiff) = diff ch
  in toEnum $ (fromEnum ch) - (fromEnum chDiff) + intDiff