[boost] grammar productions without virtual dispatch (was Re: [preprocessor] use case: named parameters for macros

From: Larry Evans (cppljevans_at_[hidden])
Date: 2006-10-25 08:38:19

On 10/25/2006 05:30 AM, Tobias Schwinger wrote:
[snip]
 >
 > Well, the experiment was driven by the question whether it would be
 > possible to add more features of spirit::rule to a macro-based
 > replacement that uses typeof instead of virtual dispatch (see
 > boost/spirit/utility/rule_parser.hpp, note: no named parameters in
 > there, yet) without compromising the interface or even making it
 > better.

The zip file:

   <boost-vault>/Template Metaprogramming/proto_static_disp.zip

uses g++ typeof, CRTP, and mpl::fold to do what sounds like something
similar, i.e. eliminate the virtual dispatch.  IIRC, the CRTP was
needed since the parse functions were mutually recursive and CRTP
allowed them to be defined in the same class, or something like that.

Maybe viewing your code would give me some ideas about how to tweak
proto_static_disp.  Any chance you could post it?