vmd/tuple/size.hpp

0001
0002 //  (C) Copyright Edward Diener 2015
0003 //  Use, modification and distribution are subject to the Boost Software License,
0004 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0005 //  http://www.boost.org/LICENSE_1_0.txt).
0006
0007 #if !defined(BOOST_VMD_TUPLE_SIZE_HPP)
0008 #define BOOST_VMD_TUPLE_SIZE_HPP
0009
0010 #include <boost/vmd/detail/setup.hpp>
0011
0012 #if BOOST_PP_VARIADICS
0013
0014 #include <boost/preprocessor/control/iif.hpp>
0015 #include <boost/preprocessor/tuple/size.hpp>
0016 #include <boost/vmd/identity.hpp>
0017 #include <boost/vmd/is_empty.hpp>
0018
0019 /*
0020
0021   The succeeding comments in this file are in doxygen format.
0022
0023 */
0024
0025 /** \file
0026 */
0027
0028 /** \def BOOST_VMD_TUPLE_SIZE(tuple)
0029
0030     \brief  expands to the size of the tuple passed to it.
0031
0032     tuple = tuple whose size is to be extracted.
0033
0034     If the tuple is an empty tuple its size is 0.
0035     Otherwise the result is the number of elements in the tuple.
0036 */
0037
0038 #define BOOST_VMD_TUPLE_SIZE(tuple) \
0039     BOOST_VMD_IDENTITY_RESULT \
0040         ( \
0041         BOOST_PP_IIF \
0042             ( \
0043             BOOST_VMD_IS_EMPTY(tuple), \
0044             BOOST_VMD_IDENTITY(0), \
0045             BOOST_PP_TUPLE_SIZE \
0046             ) \
0047         (tuple) \
0048         ) \
0049 /**/
0050
0051 #endif /* BOOST_PP_VARIADICS */
0052 #endif /* BOOST_VMD_TUPLE_SIZE_HPP */