boost/preprocessor/list/first_n.hpp
# /* Copyright (C) 2001 # * Housemarque Oy # * http://www.housemarque.com # * # * 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 Paul Mensonides (2002) */ # # /* See http://www.boost.org for most recent version. */ # # ifndef BOOST_PREPROCESSOR_LIST_FIRST_N_HPP # define BOOST_PREPROCESSOR_LIST_FIRST_N_HPP # # include <boost/preprocessor/arithmetic/dec.hpp> # include <boost/preprocessor/config/config.hpp> # include <boost/preprocessor/control/while.hpp> # include <boost/preprocessor/list/adt.hpp> # include <boost/preprocessor/list/reverse.hpp> # include <boost/preprocessor/tuple/elem.hpp> # include <boost/preprocessor/tuple/rem.hpp> # # /* BOOST_PP_LIST_FIRST_N */ # # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG() # define BOOST_PP_LIST_FIRST_N(count, list) BOOST_PP_LIST_REVERSE(BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL)))) # else # define BOOST_PP_LIST_FIRST_N(count, list) BOOST_PP_LIST_FIRST_N_I(count, list) # define BOOST_PP_LIST_FIRST_N_I(count, list) BOOST_PP_LIST_REVERSE(BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL)))) # endif # # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG() # define BOOST_PP_LIST_FIRST_N_P(d, data) BOOST_PP_TUPLE_ELEM(3, 0, data) # else # define BOOST_PP_LIST_FIRST_N_P(d, data) BOOST_PP_LIST_FIRST_N_P_I data # define BOOST_PP_LIST_FIRST_N_P_I(c, l, nl) c # endif # # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MWCC() # define BOOST_PP_LIST_FIRST_N_O(d, data) BOOST_PP_LIST_FIRST_N_O_D data # else # define BOOST_PP_LIST_FIRST_N_O(d, data) BOOST_PP_LIST_FIRST_N_O_D(BOOST_PP_TUPLE_ELEM(3, 0, data), BOOST_PP_TUPLE_ELEM(3, 1, data), BOOST_PP_TUPLE_ELEM(3, 2, data)) # endif # # define BOOST_PP_LIST_FIRST_N_O_D(c, l, nl) (BOOST_PP_DEC(c), BOOST_PP_LIST_REST(l), (BOOST_PP_LIST_FIRST(l), nl)) # # /* BOOST_PP_LIST_FIRST_N_D */ # # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG() # define BOOST_PP_LIST_FIRST_N_D(d, count, list) BOOST_PP_LIST_REVERSE_D(d, BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE_ ## d(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL)))) # else # define BOOST_PP_LIST_FIRST_N_D(d, count, list) BOOST_PP_LIST_FIRST_N_D_I(d, count, list) # define BOOST_PP_LIST_FIRST_N_D_I(d, count, list) BOOST_PP_LIST_REVERSE_D(d, BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE_ ## d(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL)))) # endif # # endif