IPv6 address parsing

Hello,

I'm moving on to IPv6 address parsing, which grammar is a super set,
sort of, of IPv4.

Basically modeled after the IPv6 grammar, more or less. I am using the
digit-wise IPv4 parsing approach here instead of uint_parser, because
I need the entire string to parse, from what I understand, and
according to RFC 5954 section 4.1.

I was also having difficulty getting "repeat" to work quite right.

_dot = ".";
_col = ":";
_col_x2 = "::";

/* TODO: TBD: This "may" work, except I really do not want to parse actual
INTEGERS, but rather them as STRINGS. */

// _dec_octet = uint_parser<std::uint8_t, 10, 1, 3>();

qi::rule<Iterator> _dec_octet = (
    char_('0')
    | char_('1') >> -(digit >> -digit)
    | char_('2') >> (
        char_('0', '4') >> -digit
        | char_('5') >> -char_('0', '5')
        | char_('6', '9')
        )
    | char_('3', '9') >> -digit
    );

qi::rule<Iterator> _ipv4_addr = _dec_octet >> repeat(3)[_dot >> _dec_octet];
// or, qi::rule<Iterator> _ipv4_addr = _dec_octet >> _dot >>
_dec_octet >> _dot >> _dec_octet >> _dot >> _dec_octet;

qi::rule<Iterator> _h16 = repeat(1, 4)[hex];
//_h16 = hex >> -(hex >> -(hex >> -hex));
qi::rule<Iterator> _h16_col = _h16 >> _col;
qi::rule<Iterator> _ls32 = _h16_col >> _h16 | _ipv4_addr;

qi::rule<Iterator> _ipv6_addr
    = repeat(6)[_h16_col] >> _ls32
    | _col_x2 >> repeat(5)[_h16_col] >> _ls32
    | -(_h16) >> _col_x2 >> repeat(4)[_h16_col] >> _ls32
    | -(_h16_col >> _h16) >> _col_x2 >> repeat(3)[_h16_col] >> _ls32
    | -(repeat(1, 2)[_h16_col] >> _h16) >> _col_x2 >>
repeat(2)[_h16_col] >> _ls32
    | -(repeat(1, 3)[_h16_col] >> _h16) >> _col_x2 >> _h16_col >> _ls32
    | -(repeat(1, 4)[_h16_col] >> _h16) >> _col_x2 >> _ls32
    | -(repeat(1, 5)[_h16_col] >> _h16) >> _col_x2 >> _h16
    | -(repeat(1, 6)[_h16_col] >> _h16) >> _col_x2
    ;

qi::rule<Iterator> _start = _ipv6_addr >> eoi;

ref: http://www.ietf.org/rfc/rfc5954.txt, section 4.1 Resolution for
Extra Colon in IPv4-Mapped IPv6 Address

I'll cook up a web program example if necessary, just wanted to get
some initial feedback.

Thoughts?

Thanks!

Regards,

Michael Powell

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