On Thu, Aug 12, 2004 at 07:03:57PM -0700, Paul Mensonides wrote:
From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Rene Rivera
[snip]
a look at the preprocessor library but I couldnt come up with a solution. Is there an alternative to the macros for registering types? (A sample program exhibiting what I am trying is attached.) [snip] // Doesn't work (wrong number of macro arguments ): // BOOST_CLASS_EXPORT( DerivedStatus< Algo< int, double > > );
Did you try using BOOST_PP_COMMA ?? For example:
BOOST_CLASS_EXPORT( DerivedStatus< Algo< int BOOST_PP_COMMA double > > );
Should be with nullary parentheses:
BOOST_CLASS_EXPORT( DerivedStatus< Algo<int BOOST_PP_COMMA() double > > );
[...]
The COMMA() trick will only work through one level of macro expansion.
Unfortunately, the serialization lib's export macros go through several levels. Therefore, replacing the commas by BOOST_PP_COMMA() does not help. (I tried it a few minutes ago.)
Incidently, do we have a function argument mapping for the common case of this type of thing?
E.g.
template<class> struct pack;
template<class T> struct pack<void (T)> { typedef T type; };
BOOST_CLASS_EXPORT( pack<void (DerivedStatus< Algo<int, double > >)>::type );
That did the trick! Great! I am not sure which of Boost's libraries is the most adequate place for such a tool (preprocessor? mpl?), but it is certainly valuable. And if / once there is such a tool in Boost, then the documentation of macros that are likely to take classes genareted from templates as arguments should refer to it. Regards Christoph -- http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/cludwig.html LiDIA: http://www.informatik.tu-darmstadt.de/TI/LiDIA/Welcome.html