on 19.08.2009 at 9:50 joel wrote :
THis may end up as a test case for the general numerical functions library I'm trying to generate out of my Boost.SIMD proposal. In a large scope, it provides a large number of stub functions that are tag dispatched rather efficiently based on "arithmetic"-like value types. So basically, it defines 150+ functions that looks at their parameters and decide which implementation to use at compile-time. I use that to discriminate between scalar and SIMD functions, but if you "tag" this bignum class correctly and follow my extension mecanism, then we can statically choose between implementation. Roughly : bignum<> x; bignum<impl::gmp> y; x = abs(x); <-- call the "standard bignum" implementation y = abs(y); <-- call the GMP implementation
i consider it a poor solution if i want debug version to use native c++ code and release version to use a back end i would be forced to type something like #ifdef NDEBUG typedef bignum<impl::gmp> mybignum; //release #elif typedef bignum<> mybignum; //debug #endif and to replicate it in every compilation unit what comes to my mind is for example build main.cpp funcs.cpp -dUSE_SPECIFIC_BACK_END -dNDEBUG for release version and build main.cpp funcs.cpp for debug version (i hope you got the point) note that i decide to use it or not by leaving the code unchanged or to enable back end explicitly in code i can #include <bignum/specific_back_end.h> -- Pavel