[boost] Re: Re: Spirit and typeof [was typeof]

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2004-05-05 11:08:29

"Reece Dunn" <msclrhd_at_[hidden]> wrote

> One question though: I have a parser where I have created several external
> grammars to help modularize the grammar and employ the trick suggested in
> the techniques section (c.f. sub-grammar):
>
>       using namespace boost::spirit;
>
>       struct identifier_parser: public sub_grammar< identifier_parser >
>       {
>          public:
>             typedef sequence_t
>             <
>                alternative< alpha_parser, chlit<> >,
>                kleene_alternative_t< alnum_parser, chlit<> >::type
>             >::type
> start_t;
>          public:
>             start_t                    start;
>          public:
>             inline           identifier_parser():
>                start
>                (
>                   ( alpha_p | '_' ) >> *( alnum_p | '_' )
>                )
>             {
>             }
>       } identifier;
>
> NOTE: This is using various type construction helpers.
>
> Once you have a (sub-)rule like this, you can use it like:
>
>    rule_t<ScannerT> tagName = !( identifier >> ':' ) >> identifier;
>
> I was wondering if this would cause any major problems when implemented
with
> the typeof/auto hack (since it could then be implemented as a grammar).

I think you would just have to register your identifier_parser class.  The
typeof system then would treat it as an atom and not care what is behind it.

Regards,
Arkadiy