boost/preprocessor/facilities/va_opt.hpp

   1 # /* **************************************************************************
   2 #  *                                                                          *
   3 #  *     (C) Copyright Edward Diener 2019.
   4 #  *     Distributed under the Boost Software License, Version 1.0. (See
   5 #  *     accompanying file LICENSE_1_0.txt or copy at
   6 #  *     http://www.boost.org/LICENSE_1_0.txt)
   7 #  *                                                                          *
   8 #  ************************************************************************** */
   9 #
  10 # /* See http://www.boost.org for most recent version. */
  11 #
  12 # ifndef BOOST_PREPROCESSOR_FACILITIES_VA_OPT_HPP
  13 # define BOOST_PREPROCESSOR_FACILITIES_VA_OPT_HPP
  14 # include <boost/preprocessor/variadic/has_opt.hpp>
  15 # if BOOST_PP_VARIADIC_HAS_OPT()
  16 # include <boost/preprocessor/control/iif.hpp>
  17 # include <boost/preprocessor/facilities/check_empty.hpp>
  18 # include <boost/preprocessor/tuple/rem.hpp>
  19 # define BOOST_PP_VA_OPT_IMPL(atuple) \
  20     BOOST_PP_TUPLE_REM() atuple       \
  21 /**/
  22 # define BOOST_PP_VA_OPT(rdata,rempty,...)     \
  23     BOOST_PP_VA_OPT_IMPL                       \
  24         (                                      \
  25         BOOST_PP_IIF                           \
  26             (                                  \
  27             BOOST_PP_CHECK_EMPTY(__VA_ARGS__), \
  28             rempty,                            \
  29             rdata                              \
  30             )                                  \
  31         )                                      \
  32 /**/
  33 # endif /* BOOST_PP_VARIADIC_HAS_OPT() */
  34 # endif /* BOOST_PREPROCESSOR_FACILITIES_VA_OPT_HPP */