Re: Domain name parser not working

On Mon, Jan 1, 2018 at 7:11 PM, Michael Powell <[email protected]> wrote:
> 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

I tried a little bit different version, IMO a little closer to the RFC
if not exactly:

https://wandbox.org/permlink/1sDTqnFphTA2egDu

Notwithstanding the roll up in to std::vector of std::string, and
ultimately ast::address.

> 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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