[preprocessor] [variadic] VMD_SIZE using ADD -- why?
Hello all, I am using the VMD Boost Library Under Construction to handle variadic macros. On MVSC, this library uses PP_ADD to calculate the variadic size VMD_SIZE(__VA_ARGS__). However, it does not provide a reentrant version of VMD_SIZE (like VMD_SIZE_D) which is a problem when nesting size calculations within while iterations because PP_ADD uses PP_WHILE. I think, if this implementation is kept, the library should also provide the reentrant variant VMD_SIZE_D that invokes PP_ADD_D instead of PP_ADD. #if defined(BOOST_MSVC) #define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE(...) \ BOOST_PP_ADD(BOOST_DETAIL_PP_VMD_DETAIL_APPLY(BOOST_DETAIL_PP_VMD_DETAIL_ARG_N, (__VA_ARGS__, BOOST_DETAIL_PP_VMD_DETAIL_RSEQ_N())),0) \ /**/ #else #define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE(...) \ BOOST_DETAIL_PP_VMD_DETAIL_APPLY(BOOST_DETAIL_PP_VMD_DETAIL_ARG_N, (__VA_ARGS__, BOOST_DETAIL_PP_VMD_DETAIL_RSEQ_N())) \ /**/ #endif BTW, why is PP_ADD(size, 0) used on MSVC? If this is just for forcing proper macro expansion, I think other techniques (like the ones used by PP_EXPAND) should be used so no PP_WHILE reentrancy dependency is introduced. Thanks, --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-preprocessor-variadic-VMD-SIZE-usin... Sent from the Boost - Dev mailing list archive at Nabble.com.
Edward Diener-3 wrote:
OK, I'll update to the latest rev. Thanks :) --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-preprocessor-variadic-VMD-SIZE-usin... Sent from the Boost - Dev mailing list archive at Nabble.com.
lcaminiti wrote:
For example, something like this should work instead of using PP_ADD(size, 0): #if defined(BOOST_MSVC) # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MWCC() && ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_DMC() # define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND(x) BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND_I(x) # else # define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND(x) BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND_OO((x)) # define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND_OO(par) BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND_I ## par # endif # define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND_I(x) x #define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE(...) \ BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE_EXPAND(BOOST_DETAIL_PP_VMD_DETAIL_APPLY(BOOST_DETAIL_PP_VMD_DETAIL_ARG_N, (__VA_ARGS__, BOOST_DETAIL_PP_VMD_DETAIL_RSEQ_N()))) \ /**/ #else #define BOOST_DETAIL_PP_VMD_DETAIL_DATA_SIZE(...) \ BOOST_DETAIL_PP_VMD_DETAIL_APPLY(BOOST_DETAIL_PP_VMD_DETAIL_ARG_N, (__VA_ARGS__, BOOST_DETAIL_PP_VMD_DETAIL_RSEQ_N())) \ /**/ #endif --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-preprocessor-variadic-VMD-SIZE-usin... Sent from the Boost - Dev mailing list archive at Nabble.com.
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Edward Diener -
lcaminiti