Hi Kevin! On Mon, Jul 21, 2008 at 9:03 PM, Kevin Jenkins <gameprogrammer@rakkar.org> wrote:

Is there any way to automate this, to support from 0 to n parameters?

template <class P1, class P2, class P3, class P4, class P5> bool DoIt(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5) {

Boost.Preprocessor would do that. Create two files, which I'll call: main.hpp implementation.hpp In main.hpp: #include <boost/preprocessor/repetition.hpp> #include <boost/preprocessor/iteration/iterate.hpp> #define NUM_FUNCTION_PARAMS 8 // Or however many you need. // Define the function for 1 to 8 arguments. #define BOOST_PP_ITERATION_LIMITS(1, NUM_FUNCTION_PARAMS); #define BOOST_PP_FILENAME_1 "implementation.hpp" #include BOOST_PP_ITERATE() And then in implementation.hpp: // Note: If you want to support 0 arguments, you'll need to use BOOST_PP_IF // to only optionally include the template declaration. I'd recommend just putting the // argless version into main.hpp, unless the function is quite complex. template <BOOST_PP_ENUM_PARAMS(N, class Param)> inline void MyFunc(BOST_PP_ENUM_BINARY_PARAMS(N, Param, p)) { #define DO_THAT(n) DoThat<BOOST_PP_CAT(P, n)>(BOOST_PP_CAT(p, n)); BOOST_PP_REPEAT(N, DO_THAT,) #undef DO_THAT } Hope that helps - and can't promise it will immediately compile! I do this in the proposed Extension and Reflection libraries a few times. The best example is probably in the adaptable_factory class, where I wanted to support calling a factory function without knowing its arguments: http://svn.boost.org/trac/boost/browser/sandbox/boost/extension/impl/adaptab... http://svn.boost.org/trac/boost/browser/sandbox/boost/extension/adaptable_fa... Let me know if you have problems getting your function to compile. Also, with Boost.Preprocessor, "gcc -E" is your best friend. Good luck! Jeremy Pack http://boost-extension.blogspot.com

Kevin Jenkins wrote:

Is there any way to automate this, to support from 0 to n parameters?

template <class P1, class P2, class P3, class P4, class P5> bool DoIt(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5) { DoThat<P1>(p1); DoThat<P2>(p2); DoThat<P3>(p3); DoThat<P4>(p4); DoThat<P5>(p5); }

I think you can do it using Boost.Fusion or Boost.Preprocessor. For boost.fusion, I think you can you define the function to take a ::boost::fusion::vector, and use for_each to call a polymorphic function that calls DoThat. Then you make an unfused function from that. For boost.Preprocessor, you can generate a signature using macros like BOOST_PP_ENUM_PARAMS / ENUM_BINARY_PARAMS / REPEAT . --John