boost/vmd/is_empty_array.hpp
// (C) Copyright Edward Diener 2011-2015
// Use, modification and distribution are subject to 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).
#if !defined(BOOST_VMD_IS_EMPTY_ARRAY_HPP)
#define BOOST_VMD_IS_EMPTY_ARRAY_HPP
#include <boost/vmd/detail/setup.hpp>
#if BOOST_PP_VARIADICS
#include <boost/preprocessor/control/iif.hpp>
#include <boost/vmd/is_array.hpp>
#include <boost/vmd/identity.hpp>
#include <boost/vmd/detail/is_empty_array.hpp>
/*
The succeeding comments in this file are in doxygen format.
*/
/** \file
*/
/** \def BOOST_VMD_IS_EMPTY_ARRAY(sequence)
\brief Tests whether a sequence is an empty Boost PP array.
An empty Boost PP array is a two element tuple where the first
size element is 0 and the second element is a tuple with a single
empty element, ie. '(0,())'.
sequence = a possible empty array
returns = 1 if the sequence is an empty Boost PP array,
0 if it is not.
The macro will generate a preprocessing error if the sequence
is in the form of an array but its first tuple element, instead
of being a number, is a preprocessor token which VMD cannot parse,
as in the example '(&0,())' which is a valid tuple but an invalid
array.
*/
#define BOOST_VMD_IS_EMPTY_ARRAY(sequence) \
BOOST_VMD_IDENTITY_RESULT \
( \
BOOST_PP_IIF \
( \
BOOST_VMD_IS_ARRAY(sequence), \
BOOST_VMD_DETAIL_IS_EMPTY_ARRAY_SIZE, \
BOOST_VMD_IDENTITY(0) \
) \
(sequence) \
) \
/**/
/** \def BOOST_VMD_IS_EMPTY_ARRAY_D(d,sequence)
\brief Tests whether a sequence is an empty Boost PP array. Re-entrant version.
An empty Boost PP array is a two element tuple where the first
size element is 0 and the second element is a tuple with a single
empty element, ie. '(0,())'.
d = The next available BOOST_PP_WHILE iteration. <br/>
sequence = a possible empty array
returns = 1 if the sequence is an empty Boost PP array,
0 if it is not.
The macro will generate a preprocessing error if the sequence
is in the form of an array but its first tuple element, instead
of being a number, is a preprocessor token which VMD cannot parse,
as in the example '(&0,())' which is a valid tuple but an invalid
array.
*/
#define BOOST_VMD_IS_EMPTY_ARRAY_D(d,sequence) \
BOOST_VMD_IDENTITY_RESULT \
( \
BOOST_PP_IIF \
( \
BOOST_VMD_IS_ARRAY_D(d,sequence), \
BOOST_VMD_DETAIL_IS_EMPTY_ARRAY_SIZE, \
BOOST_VMD_IDENTITY(0) \
) \
(sequence) \
) \
/**/
#endif /* BOOST_PP_VARIADICS */
#endif /* BOOST_VMD_IS_EMPTY_ARRAY_HPP */