1 2 // (C) Copyright Edward Diener 2015 3 // Use, modification and distribution are subject to the Boost Software License, 4 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at 5 // http://www.boost.org/LICENSE_1_0.txt). 6 7 #if !defined(BOOST_VMD_SEQ_POP_BACK_HPP) 8 #define BOOST_VMD_SEQ_POP_BACK_HPP 9 10 #include <boost/vmd/detail/setup.hpp> 11 12 #if BOOST_PP_VARIADICS 13 14 #include <boost/preprocessor/comparison/equal.hpp> 15 #include <boost/preprocessor/control/iif.hpp> 16 #include <boost/preprocessor/seq/pop_back.hpp> 17 #include <boost/preprocessor/seq/size.hpp> 18 #include <boost/vmd/empty.hpp> 19 20 /* 21 22 The succeeding comments in this file are in doxygen format. 23 24 */ 25 26 /** \file 27 */ 28 29 /** \def BOOST_VMD_SEQ_POP_BACK(seq) 30 31 \brief pops an element from the end of a seq. 32 33 seq = seq to pop an element from. 34 35 If the seq is an empty seq the result is undefined. 36 If the seq is a single element the result is an empty seq. 37 Otherwise the result is a seq after removing the last element. 38 */ 39 40 #define BOOST_VMD_SEQ_POP_BACK(seq) \ 41 BOOST_PP_IIF \ 42 ( \ 43 BOOST_PP_EQUAL(BOOST_PP_SEQ_SIZE(seq),1), \ 44 BOOST_VMD_EMPTY, \ 45 BOOST_PP_SEQ_POP_BACK \ 46 ) \ 47 (seq) \ 48 /**/ 49 50 #endif /* BOOST_PP_VARIADICS */ 51 #endif /* BOOST_VMD_SEQ_POP_BACK_HPP */ 52