preprocessor/facilities/is_empty_variadic.hpp

0001 # /* **************************************************************************
0002 #  *                                                                          *
0003 #  *     (C) Copyright Edward Diener 2014,2019.
0004 #  *     Distributed under the Boost Software License, Version 1.0. (See
0005 #  *     accompanying file LICENSE_1_0.txt or copy at
0006 #  *     http://www.boost.org/LICENSE_1_0.txt)
0007 #  *                                                                          *
0008 #  ************************************************************************** */
0009 0010 ">#
0011 # /* See http://www.boost.org for most recent version. */
0012 0013 ">#
0014 # ifndef BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP
0015 # define BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP
0016 0017 ">#
0018 # include <boost/preprocessor/config/config.hpp>
0019 # include <boost/preprocessor/punctuation/is_begin_parens.hpp>
0020 # include <boost/preprocessor/facilities/detail/is_empty.hpp>
0021 0022 ">#
0023 #if BOOST_PP_VARIADICS_MSVC && _MSC_VER <= 1400
0024 0025 ">#
0026 #define BOOST_PP_IS_EMPTY(param) \
0027     BOOST_PP_DETAIL_IS_EMPTY_IIF \
0028       ( \
0029       BOOST_PP_IS_BEGIN_PARENS \
0030         ( \
0031         param \
0032         ) \
0033       ) \
0034       ( \
0035       BOOST_PP_IS_EMPTY_ZERO, \
0036       BOOST_PP_DETAIL_IS_EMPTY_PROCESS \
0037       ) \
0038     (param) \
0039 /**/
0040 #define BOOST_PP_IS_EMPTY_ZERO(param) 0
0041 # else
0042 # if defined(__cplusplus) && __cplusplus > 201703L
0043 # include <boost/preprocessor/variadic/has_opt.hpp>
0044 #define BOOST_PP_IS_EMPTY(...) \
0045     BOOST_PP_DETAIL_IS_EMPTY_IIF \
0046       ( \
0047       BOOST_PP_VARIADIC_HAS_OPT() \
0048       ) \
0049       ( \
0050       BOOST_PP_IS_EMPTY_OPT, \
0051       BOOST_PP_IS_EMPTY_NO_OPT \
0052       ) \
0053     (__VA_ARGS__) \
0054 /**/
0055 #define BOOST_PP_IS_EMPTY_FUNCTION2(...) \
0056     __VA_OPT__(0,) 1 \
0057 /**/
0058 #define BOOST_PP_IS_EMPTY_FUNCTION(...) \
0059     BOOST_PP_IS_EMPTY_FUNCTION2(__VA_ARGS__) \
0060 /**/
0061 #define BOOST_PP_IS_EMPTY_OPT(...) \
0062     BOOST_PP_VARIADIC_HAS_OPT_ELEM0(BOOST_PP_IS_EMPTY_FUNCTION(__VA_ARGS__),) \
0063 /**/
0064 # else
0065 #define BOOST_PP_IS_EMPTY(...) \
0066     BOOST_PP_IS_EMPTY_NO_OPT(__VA_ARGS__) \
0067 /**/
0068 # endif /* defined(__cplusplus) && __cplusplus > 201703L */
0069 #define BOOST_PP_IS_EMPTY_NO_OPT(...) \
0070     BOOST_PP_DETAIL_IS_EMPTY_IIF \
0071       ( \
0072       BOOST_PP_IS_BEGIN_PARENS \
0073         ( \
0074         __VA_ARGS__ \
0075         ) \
0076       ) \
0077       ( \
0078       BOOST_PP_IS_EMPTY_ZERO, \
0079       BOOST_PP_DETAIL_IS_EMPTY_PROCESS \
0080       ) \
0081     (__VA_ARGS__) \
0082 /**/
0083 #define BOOST_PP_IS_EMPTY_ZERO(...) 0
0084 # endif /* BOOST_PP_VARIADICS_MSVC && _MSC_VER <= 1400 */
0085 # endif /* BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP */