diff options
Diffstat (limited to 'boost/vmd/is_empty_array.hpp')
-rw-r--r-- | boost/vmd/is_empty_array.hpp | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/boost/vmd/is_empty_array.hpp b/boost/vmd/is_empty_array.hpp new file mode 100644 index 0000000000..913af70db9 --- /dev/null +++ b/boost/vmd/is_empty_array.hpp @@ -0,0 +1,98 @@ + +// (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. + 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 */ |