cpp98/impl/is_none.hpp

0001 #ifndef BOOST_METAPARSE_V1_CPP98_IMPL_IS_NONE_HPP
0002 #define BOOST_METAPARSE_V1_CPP98_IMPL_IS_NONE_HPP
0003
0004 // Copyright Abel Sinkovics (abel@sinkovics.hu)  2013.
0005 // Distributed under the Boost Software License, Version 1.0.
0006 //    (See accompanying file LICENSE_1_0.txt or copy at
0007 //          http://www.boost.org/LICENSE_1_0.txt)
0008
0009 #include <boost/metaparse/limit_one_char_except_size.hpp>
0010
0011 #include <boost/mpl/eval_if.hpp>
0012 #include <boost/mpl/bool.hpp>
0013
0014 #include <boost/preprocessor/cat.hpp>
0015 #include <boost/preprocessor/arithmetic/dec.hpp>
0016 #include <boost/preprocessor/repetition/enum_params.hpp>
0017 #include <boost/preprocessor/repetition/repeat_from_to.hpp>
0018
0019 namespace boost
0020 {
0021   namespace metaparse
0022   {
0023     namespace v1
0024     {
0025       namespace impl
0026       {
0027         template <class Stub = int>
0028         struct is_none0
0029         {
0030           template <class C>
0031           struct apply : boost::mpl::true_ {};
0032         };
0033
0034         #ifdef BOOST_METAPARSE_DEFINE_IS_NONE
0035         #  error BOOST_METAPARSE_DEFINE_IS_NONE already defined
0036         #endif
0037         #define BOOST_METAPARSE_DEFINE_IS_NONE(z, n, unused) \
0038           template <BOOST_PP_ENUM_PARAMS(n, class T)> \
0039           struct BOOST_PP_CAT(is_none, n) \
0040           { \
0041             template <class C> \
0042             struct apply : \
0043               boost::mpl::eval_if< \
0044                 boost::mpl::bool_< \
0045                   C::type::value \
0046                   == BOOST_PP_CAT(T, BOOST_PP_DEC(n))::type::value \
0047                 >, \
0048                 boost::mpl::false_, \
0049                 typename BOOST_PP_CAT(is_none, BOOST_PP_DEC(n))< \
0050                   BOOST_PP_ENUM_PARAMS(BOOST_PP_DEC(n), T) \
0051                 >::template apply<C> \
0052               > \
0053             {}; \
0054           };
0055
0056         BOOST_PP_REPEAT_FROM_TO(
0057           1,
0058           BOOST_METAPARSE_LIMIT_ONE_CHAR_EXCEPT_SIZE,
0059           BOOST_METAPARSE_DEFINE_IS_NONE,
0060           ~
0061         )
0062
0063         #undef BOOST_METAPARSE_DEFINE_IS_NONE
0064       }
0065     }
0066   }
0067 }
0068
0069 #endif
0070