Re: Domain name parser not working

On Mon, Jan 1, 2018 at 6:49 PM, Michael Powell <[email protected]> wrote:
> Hello,
>
> // Where Let is char_(/*upper/lower-case chars*/), Dig is
> char_("0123456789"), Hyp is char_('.'), and dot_ is '.'.
>
> template<typename It>
> struct DomainNameParser : boost::spirit::qi::grammar<It, Ast::Address()> {
>
>   DomainNameParser() {
>
>     _hyp = char_('-');
>     _dig = char_(DOMAIN_NAME_PARSER_DIGITS);
>     _let = char_(DOMAIN_NAME_PARSER_LOWERCASE DOMAIN_NAME_PARSER_UPPERCASE);
>
>     // A straight interpretation of the Domain Name grammar leads me to this:
>     /*qi::rule<It, std::string()>*/ _label = raw[_let >> -(*(_let |
> _dig | _hyp) >> (_let | _dig))];
>     /*qi::rule<It, Ast::Address()>*/ _start = (_label % dot_) >> eoi;
>     // ...
>
>  }
> };
>
> Assuming,
>
> struct Address {
>   std::vector<std::string> _labels;
> };
>
> BOOST_FUSION_ADAPT_STRUCT(Ast::Address,
>     (std::vector<std::string>, _labels)
> )
>
> However, this is failing to match: "E-PHUMZ8G8j1KEZG26C" in spite of
> the fact this matches the expected pattern. No skippers involved, just
> the iterator (std::string::const_iterator), and the AST, of course.
>
> For now, dropping the semantic action until I can get the parser to
> work properly. However, eventually I want to incorporate the
> validation rule:
>
> struct label_validation {
>     // Notwithstanding Qi/Fusion bits that glue it together.
>     bool operator()(std::string const& l) const {
>         return l.length() <= 63;
>     }
> };
>
> Once again I am suspicious whether Optional is working properly, never
> minding Kleene Star productions. I ended up needing to separate out
> Alternative phrases instead of the Optional before in order to make it
> work properly.
>
> Perhaps I need to capture each phrase in a rule of its own focused
> solely on std::string or char, respectively, as contrasted with the
> entire std::string?

Here's an MRP:

https://wandbox.org/permlink/cbpUPMnQ4APZeDdw

More or less based on RFC 1034: https://tools.ietf.org/html/rfc1034#section-3.5

Thoughts?

Cheers,

Michael

> Cheers,
>
> Michael Powell

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