preprocessor/facilities/is_empty_or_1.hpp

0001 # /* **************************************************************************
0002 #  *                                                                          *
0003 #  *     (C) Copyright Paul Mensonides 2003.
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 # /* See http://www.boost.org for most recent version. */
0011 #
0012 # ifndef BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_OR_1_HPP
0013 # define BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_OR_1_HPP
0014 #
0015 # include <boost/preprocessor/control/iif.hpp>
0016 # include <boost/preprocessor/facilities/empty.hpp>
0017 # include <boost/preprocessor/facilities/identity.hpp>
0018 # include <boost/preprocessor/facilities/is_1.hpp>
0019 # include <boost/preprocessor/facilities/is_empty.hpp>
0020 #
0021 # /* BOOST_PP_IS_EMPTY_OR_1 */
0022 #
0023 # define BOOST_PP_IS_EMPTY_OR_1(x) \
0024     BOOST_PP_IIF( \
0025         BOOST_PP_IS_EMPTY(x BOOST_PP_EMPTY()), \
0026         BOOST_PP_IDENTITY(1), \
0027         BOOST_PP_IS_1 \
0028     )(x) \
0029     /**/
0030 #
0031 # endif