boost_tuple/detail/build_cons.hpp

0001 /*=============================================================================
0002     Copyright (c) 2012-2014 Kohei Takahashi
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007 #if !defined(BOOST_FUSION_BUILD_CONS_10172012_0130)
0008 #define BOOST_FUSION_BUILD_CONS_10172012_0130
0009
0010 #include <boost/tuple/tuple.hpp>
0011 #include <boost/fusion/iterator/equal_to.hpp>
0012 #include <boost/fusion/iterator/next.hpp>
0013 #include <boost/fusion/iterator/value_of.hpp>
0014 #include <boost/fusion/iterator/deref.hpp>
0015
0016 namespace boost { namespace fusion { namespace detail
0017 {
0018     template <
0019         typename First
0020       , typename Last
0021       , bool is_empty = result_of::equal_to<First, Last>::value>
0022     struct build_tuple_cons;
0023
0024     template <typename First, typename Last>
0025     struct build_tuple_cons<First, Last, true>
0026     {
0027         typedef boost::tuples::null_type type;
0028
0029         BOOST_FUSION_GPU_ENABLED
0030         static type
0031         call(First const&, Last const&)
0032         {
0033             return type();
0034         }
0035     };
0036
0037     template <typename First, typename Last>
0038     struct build_tuple_cons<First, Last, false>
0039     {
0040         typedef
0041             build_tuple_cons<typename result_of::next<First>::type, Last>
0042         next_build_tuple_cons;
0043
0044         typedef boost::tuples::cons<
0045             typename result_of::value_of<First>::type
0046           , typename next_build_tuple_cons::type>
0047         type;
0048
0049         BOOST_FUSION_GPU_ENABLED
0050         static type
0051         call(First const& f, Last const& l)
0052         {
0053             typename result_of::value_of<First>::type v = *f;
0054             return type(v, next_build_tuple_cons::call(fusion::next(f), l));
0055         }
0056     };
0057 }}}
0058
0059 #endif