Hi Kevin!
On Mon, Jul 21, 2008 at 9:03 PM, Kevin Jenkins
wrote:
Is there any way to automate this, to support from 0 to n parameters?
template
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
#include
#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
inline void MyFunc(BOST_PP_ENUM_BINARY_PARAMS(N, Param, p)) {
#define DO_THAT(n) DoThat(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
