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

source code of boost/boost/vmd/is_empty_array.hpp