preprocessor/list/at.hpp

0001 # /* Copyright (C) 2001
0002 #  * Housemarque Oy
0003 #  * http://www.housemarque.com
0004 #  *
0005 #  * Distributed under the Boost Software License, Version 1.0. (See
0006 #  * accompanying file LICENSE_1_0.txt or copy at
0007 #  * http://www.boost.org/LICENSE_1_0.txt)
0008 #  */
0009 #
0010 # /* Revised by Paul Mensonides (2002) */
0011 #
0012 # /* See http://www.boost.org for most recent version. */
0013 #
0014 # ifndef BOOST_PREPROCESSOR_LIST_AT_HPP
0015 # define BOOST_PREPROCESSOR_LIST_AT_HPP
0016 #
0017 # include <boost/preprocessor/config/config.hpp>
0018 # include <boost/preprocessor/list/adt.hpp>
0019 # include <boost/preprocessor/list/rest_n.hpp>
0020 #
0021 # /* BOOST_PP_LIST_AT */
0022 #
0023 # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG()
0024 #    define BOOST_PP_LIST_AT(list, index) BOOST_PP_LIST_FIRST(BOOST_PP_LIST_REST_N(index, list))
0025 # else
0026 #    define BOOST_PP_LIST_AT(list, index) BOOST_PP_LIST_AT_I(list, index)
0027 #    define BOOST_PP_LIST_AT_I(list, index) BOOST_PP_LIST_FIRST(BOOST_PP_LIST_REST_N(index, list))
0028 # endif
0029 #
0030 # /* BOOST_PP_LIST_AT_D */
0031 #
0032 # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG()
0033 #    define BOOST_PP_LIST_AT_D(d, list, index) BOOST_PP_LIST_FIRST(BOOST_PP_LIST_REST_N_D(d, index, list))
0034 # else
0035 #    define BOOST_PP_LIST_AT_D(d, list, index) BOOST_PP_LIST_AT_D_I(d, list, index)
0036 #    define BOOST_PP_LIST_AT_D_I(d, list, index) BOOST_PP_LIST_FIRST(BOOST_PP_LIST_REST_N_D(d, index, list))
0037 # endif
0038 #
0039 # endif