Distributing an argument in a variadic macro

Question

I would like to construct a macro that takes a variable number of arguments and distributes the first argument to each of the subsequent in a format similar to the examples shown below:

Call:   MACRO(F,A)
Result: F:A

Call:   MACRO(F,A,B,C)
Result: F:A F:B F:C

I have seen https://github.com/swansontec/map-macro and the general concept of the recursion workaround through:

#define EVAL0(...) __VA_ARGS__
#define EVAL1(...) EVAL0 (EVAL0 (EVAL0 (__VA_ARGS__)))
#define EVAL2(...) EVAL1 (EVAL1 (EVAL1 (__VA_ARGS__)))
#define EVAL3(...) EVAL2 (EVAL2 (EVAL2 (__VA_ARGS__)))
#define EVAL4(...) EVAL3 (EVAL3 (EVAL3 (__VA_ARGS__)))
#define EVAL(...)  EVAL4 (EVAL4 (EVAL4 (__VA_ARGS__)))

But I cannot wrap my mind around how to apply this to my problem. Can anyone provide an example to achieve the results shown above? Thanks!

Answer 1

With Boost.PP:

#include <boost/preprocessor/seq/for_each.hpp>
#include <boost/preprocessor/variadic/to_seq.hpp>

#define TRANSFORM(r, data, elem) data:elem

#define MACRO(F, ...) \
    BOOST_PP_SEQ_FOR_EACH(TRANSFORM, F, BOOST_PP_VARIADIC_TO_SEQ(__VA_ARGS__))

Demo. This will (AFAIR) work for up to 255 arguments.