BOOST PP MAGIC

gistfile1.txt

#include <boost/preprocessor/comparison/not_equal.hpp>
#include <boost/preprocessor/punctuation/remove_parens.hpp>
#include <boost/preprocessor/tuple/pop_back.hpp>
#include <boost/preprocessor/tuple/push_back.hpp>
#include <boost/preprocessor/tuple/reverse.hpp>
#include <boost/preprocessor/variadic/to_array.hpp>

#define __COCAINE_LOG_IS_NEW_SYNTAX(...) \
    BOOST_PP_NOT_EQUAL(1, \
        BOOST_PP_LIST_FIRST( \
            BOOST_PP_VARIADIC_TO_ARRAY( \
                BOOST_PP_REMOVE_PARENS( \
                    BOOST_PP_TUPLE_ELEM(0, BOOST_PP_TUPLE_REVERSE((__VA_ARGS__))) \
                ) \
            ) \
        ) \
    )

#define __COCAINE_LOG_ADD_SOURCE(...) \
    BOOST_PP_TUPLE_PUSH_BACK( \
        BOOST_PP_TUPLE_POP_BACK((__VA_ARGS__)), \
        (::blackhole::attribute_list{ \
            BOOST_PP_REMOVE_PARENS(BOOST_PP_TUPLE_ELEM(0, BOOST_PP_TUPLE_REVERSE((__VA_ARGS__))))\
            ,{"dbg.lineno", __LINE__}\
            ,{"dbg.filename", __FILE__}\
            ,{"dbg.function", __func__ }\
            ,{"dbg.translation", __DATE__ ":" __TIME__}\
        })\
    )

#define COCAINE_LOG(__logger__, __severity__, ...) \
    ::cocaine::detail::logging::make_facade(__logger__).log(__severity__, \
        BOOST_PP_REMOVE_PARENS(\
            BOOST_PP_IF(__COCAINE_LOG_IS_NEW_SYNTAX(__VA_ARGS__), \
                __COCAINE_LOG_ADD_SOURCE(__VA_ARGS__), \
                (__VA_ARGS__)\
            )\
        )\
    )