text: # /* **************************************************************************
  #  *                                                                          *
  #  *     (C) Copyright Edward Diener 2011.                                    *
  #  *     (C) Copyright Paul Mensonides 2011.                                  *
  #  *     Distributed under the Boost Software License, Version 1.0. (See      *
  #  *     accompanying file LICENSE_1_0.txt or copy at                         *
  #  *     http://www.boost.org/LICENSE_1_0.txt)                                *
  #  *                                                                          *
  #  ************************************************************************** */
  #
  # /* Revised by Edward Diener (2020) */
  #
  # /* See http://www.boost.org for most recent version. */
  #
  # ifndef BOOST_PREPROCESSOR_VARIADIC_SIZE_HPP
  # define BOOST_PREPROCESSOR_VARIADIC_SIZE_HPP
  #
  # include "boost/preprocessor/cat.hpp"
  # include "boost/preprocessor/config/config.hpp"
  # include "boost/preprocessor/control/iif.hpp"
  # include "boost/preprocessor/facilities/check_empty.hpp"
  #
  # /* BOOST_PP_VARIADIC_SIZE */
  #
  # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_STRICT()
  #
  #    if BOOST_PP_VARIADIC_HAS_OPT()
  #       if BOOST_PP_VARIADICS_MSVC
  #           define BOOST_PP_VARIADIC_SIZE_NOT_EMPTY(...) BOOST_PP_CAT(BOOST_PP_VARIADIC_SIZE_I(__VA_ARGS__, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,),)
  #       else
  #           define BOOST_PP_VARIADIC_SIZE_NOT_EMPTY(...) BOOST_PP_VARIADIC_SIZE_I(__VA_ARGS__, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,)
  #       endif
  #       define BOOST_PP_VARIADIC_SIZE_EMPTY(...) 0
  #       define BOOST_PP_VARIADIC_SIZE(...) BOOST_PP_IIF(BOOST_PP_CHECK_EMPTY(__VA_ARGS__),BOOST_PP_VARIADIC_SIZE_EMPTY,BOOST_PP_VARIADIC_SIZE_NOT_EMPTY)(__VA_ARGS__)
  #    elif BOOST_PP_VARIADICS_MSVC
  #       define BOOST_PP_VARIADIC_SIZE(...) BOOST_PP_CAT(BOOST_PP_VARIADIC_SIZE_I(__VA_ARGS__, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,),)
  #    else
  #       define BOOST_PP_VARIADIC_SIZE(...) BOOST_PP_VARIADIC_SIZE_I(__VA_ARGS__, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,)
  #    endif
  #    define BOOST_PP_VARIADIC_SIZE_I(e0, e1, e2, e3, e4, e5, e6, e7, e8, e9, e10, e11, e12, e13, e14, e15, e16, e17, e18, e19, e20, e21, e22, e23, e24, e25, e26, e27, e28, e29, e30, e31, e32, e33, e34, e35, e36, e37, e38, e39, e40, e41, e42, e43, e44, e45, e46, e47, e48, e49, e50, e51, e52, e53, e54, e55, e56, e57, e58, e59, e60, e61, e62, e63, size, ...) size
  #
  # else
  #
  #    if BOOST_PP_VARIADIC_HAS_OPT()
  #       define BOOST_PP_VARIADIC_SIZE_EMPTY(...) 0
  #       define BOOST_PP_VARIADIC_SIZE(...) BOOST_PP_IIF(BOOST_PP_CHECK_EMPTY(__VA_ARGS__),BOOST_PP_VARIADIC_SIZE_EMPTY,BOOST_PP_VARIADIC_DO_SIZE)(__VA_ARGS__)
  #    else
  #       define BOOST_PP_VARIADIC_SIZE(...) BOOST_PP_VARIADIC_DO_SIZE(__VA_ARGS__)
  #    endif
  #
  # include "boost/preprocessor/config/limits.hpp"
  #
  # if BOOST_PP_LIMIT_VARIADIC == 64
  # include "boost/preprocessor/variadic/limits/size_64.hpp"
  # elif BOOST_PP_LIMIT_VARIADIC == 128
  # include "boost/preprocessor/variadic/limits/size_128.hpp"
  # elif BOOST_PP_LIMIT_VARIADIC == 256
  # include "boost/preprocessor/variadic/limits/size_256.hpp"
  # else
  # error Incorrect value for the BOOST_PP_LIMIT_TUPLE limit
  # endif
  #
  # endif
  #
  # endif
  