1 | |
2 | // (C) Copyright Edward Diener 2011-2015 |
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_IS_EMPTY_ARRAY_HPP) |
8 | #define BOOST_VMD_IS_EMPTY_ARRAY_HPP |
9 | |
10 | #include <boost/vmd/detail/setup.hpp> |
11 | |
12 | #if BOOST_PP_VARIADICS |
13 | |
14 | #include <boost/preprocessor/control/iif.hpp> |
15 | #include <boost/vmd/is_array.hpp> |
16 | #include <boost/vmd/identity.hpp> |
17 | #include <boost/vmd/detail/is_empty_array.hpp> |
18 | |
19 | /* |
20 | |
21 | The succeeding comments in this file are in doxygen format. |
22 | |
23 | */ |
24 | |
25 | /** \file |
26 | */ |
27 | |
28 | /** \def BOOST_VMD_IS_EMPTY_ARRAY(sequence) |
29 | |
30 | \brief Tests whether a sequence is an empty Boost PP array. |
31 | |
32 | An empty Boost PP array is a two element tuple where the first |
33 | size element is 0 and the second element is a tuple with a single |
34 | empty element, ie. '(0,())'. |
35 | |
36 | sequence = a possible empty array |
37 | |
38 | returns = 1 if the sequence is an empty Boost PP array |
39 | 0 if it is not. |
40 | |
41 | The macro will generate a preprocessing error if the sequence |
42 | is in the form of an array but its first tuple element, instead |
43 | of being a number, is a preprocessor token which VMD cannot parse, |
44 | as in the example '(&0,())' which is a valid tuple but an invalid |
45 | array. |
46 | |
47 | */ |
48 | |
49 | #define BOOST_VMD_IS_EMPTY_ARRAY(sequence) \ |
50 | BOOST_VMD_IDENTITY_RESULT \ |
51 | ( \ |
52 | BOOST_PP_IIF \ |
53 | ( \ |
54 | BOOST_VMD_IS_ARRAY(sequence), \ |
55 | BOOST_VMD_DETAIL_IS_EMPTY_ARRAY_SIZE, \ |
56 | BOOST_VMD_IDENTITY(0) \ |
57 | ) \ |
58 | (sequence) \ |
59 | ) \ |
60 | /**/ |
61 | |
62 | /** \def BOOST_VMD_IS_EMPTY_ARRAY_D(d,sequence) |
63 | |
64 | \brief Tests whether a sequence is an empty Boost PP array. Re-entrant version. |
65 | |
66 | An empty Boost PP array is a two element tuple where the first |
67 | size element is 0 and the second element is a tuple with a single |
68 | empty element, ie. '(0,())'. |
69 | |
70 | d = The next available BOOST_PP_WHILE iteration. |
71 | sequence = a possible empty array |
72 | |
73 | returns = 1 if the sequence is an empty Boost PP array |
74 | 0 if it is not. |
75 | |
76 | The macro will generate a preprocessing error if the sequence |
77 | is in the form of an array but its first tuple element, instead |
78 | of being a number, is a preprocessor token which VMD cannot parse, |
79 | as in the example '(&0,())' which is a valid tuple but an invalid |
80 | array. |
81 | |
82 | */ |
83 | |
84 | #define BOOST_VMD_IS_EMPTY_ARRAY_D(d,sequence) \ |
85 | BOOST_VMD_IDENTITY_RESULT \ |
86 | ( \ |
87 | BOOST_PP_IIF \ |
88 | ( \ |
89 | BOOST_VMD_IS_ARRAY_D(d,sequence), \ |
90 | BOOST_VMD_DETAIL_IS_EMPTY_ARRAY_SIZE, \ |
91 | BOOST_VMD_IDENTITY(0) \ |
92 | ) \ |
93 | (sequence) \ |
94 | ) \ |
95 | /**/ |
96 | |
97 | #endif /* BOOST_PP_VARIADICS */ |
98 | #endif /* BOOST_VMD_IS_EMPTY_ARRAY_HPP */ |
99 | |