"Paul Mensonides" <pmenso57@comcast.net> wrote
It isn't usually the case that preprocessor metaprogramming is used to do type computation. It is possible, of course, given enough scaffolding, but templates are much more naturally suited to it. Types as values just doesn't scale with the preprocessor. It is common, OTOH, to generate a template-based solution with the preprocessor. Thus, what exactly are you trying to do?
So I am wonderring if there is any facility in the preprocessor (or in the Boost.Preprocessor) that would allow me to do this.
There isn't a facility to do it directly in the pp-lib, but it is
I am trying to extend my typeof emulation system (see http://groups.yahoo.com/group/boost/files/typeof.zip) with the ability to conveniently support integral template parameters. I am generating partial template specializations that are responsible for encoding/decoding of a template instantiation. In such specialization, type parameters are handled differently from integral parameters in a few different aspects. I could encapsulate these aspects in a preprocessor tuple, and provide macros to generate these tuples, so that I would get something like this from the user: template<typename T, bool b, unsigned int n> class foo; REGISTER_TEMPLATE(foo, 3, ( TYPE_ARG, INTEGRAL_ARG(bool), INTEGRAL_ARG(unsigned int) )); // this expands into encoding/decoding specializations Here both TYPE_ARG and INTEGRAL_ARG(x) expand into a preprocessor tuple where all the necessary information is contained, so that I can generate my specializations. This looks implementable, but I am just trying to explore an alternative, where the user would just specify: REGISTER_TEMPLATE(foo, 3, (typename, bool, unsigned int)); And this requires to associate a few properties with, e.g., "unsigned int", which caused my original question. possible. Any information on the subject would be greatly appreciated. Thanks, Arkadiy