1 # /* **************************************************************************
2 #  *                                                                          *
3 #  *     (C) Copyright Edward Diener 2015.
4 #  *     Distributed under the Boost Software License, Version 1.0. (See
5 #  *     accompanying file LICENSE_1_0.txt or copy at
6 #  *     http://www.boost.org/LICENSE_1_0.txt)
7 #  *                                                                          *
8 #  ************************************************************************** */
9 #
10 # /* See http://www.boost.org for most recent version. */
11 #
12 # ifndef BOOST_PREPROCESSOR_SEQ_DETAIL_IS_EMPTY_HPP
13 # define BOOST_PREPROCESSOR_SEQ_DETAIL_IS_EMPTY_HPP
14 #
15 # include <boost/preprocessor/config/config.hpp>
16 # include <boost/preprocessor/arithmetic/dec.hpp>
17 # include <boost/preprocessor/logical/bool.hpp>
18 # include <boost/preprocessor/logical/compl.hpp>
19 # include <boost/preprocessor/seq/size.hpp>
20 #
21 /* An empty seq is one that is just BOOST_PP_SEQ_NIL */
22 #
23 # define BOOST_PP_SEQ_DETAIL_IS_EMPTY(seq) \
24     BOOST_PP_COMPL \
25         ( \
26         BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY(seq) \
27         ) \
28 /**/
29 #
30 # define BOOST_PP_SEQ_DETAIL_IS_EMPTY_SIZE(size) \
31     BOOST_PP_COMPL \
32         ( \
33         BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(size) \
34         ) \
35 /**/
36 #
37 # define BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY(seq) \
38     BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(BOOST_PP_SEQ_DETAIL_EMPTY_SIZE(seq)) \
39 /**/
40 #
41 # define BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(size) \
42     BOOST_PP_BOOL(size) \
43 /**/
44 #
45 # define BOOST_PP_SEQ_DETAIL_EMPTY_SIZE(seq) \
46     BOOST_PP_DEC(BOOST_PP_SEQ_SIZE(seq (nil))) \
47 /**/
48 #
49 # endif
50