ParserInput reading directly off a ByteString. (Based on the ByteArrayBasedParserInput)
This avoids a separate decoding step but assumes that each byte represents exactly one character,
which is encoded by ISO-8859-1!
You can therefore use this ParserInput type only if you know that all input will be
ISO-8859-1-encoded,
or only contains 7-bit ASCII characters (which is a subset of ISO-8859-1)!
Note that this ParserInput type will NOT work with general UTF-8-encoded input as this can contain
character representations spanning multiple bytes. However, if you know that your input will only ever contain
7-bit ASCII characters (0x00-0x7F) then UTF-8 is fine, since the first 127 UTF-8 characters are
encoded with only one byte that is identical to 7-bit ASCII and ISO-8859-1.