metaparse/v1/if_.hpp

0001 #ifndef BOOST_METAPARSE_V1_IF__HPP
0002 #define BOOST_METAPARSE_V1_IF__HPP
0003
0004 // Copyright Abel Sinkovics (abel@sinkovics.hu)  2009 - 2010.
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/v1/accept.hpp>
0010 #include <boost/metaparse/v1/is_error.hpp>
0011
0012 #include <boost/mpl/if.hpp>
0013
0014 namespace boost
0015 {
0016   namespace metaparse
0017   {
0018     namespace v1
0019     {
0020       template <class P, class T, class F>
0021       struct if_
0022       {
0023         typedef if_ type;
0024
0025         template <class S, class Pos>
0026         struct apply :
0027           accept<
0028             typename boost::mpl::if_<
0029               is_error<typename P::template apply<S, Pos> >,
0030               F,
0031               T
0032             >::type,
0033             S,
0034             Pos
0035           >
0036         {};
0037       };
0038     }
0039   }
0040 }
0041
0042 #endif
0043