ceph/src/boost/libs/metaparse/include/boost/metaparse/v1/always.hpp

   1 #ifndef BOOST_METAPARSE_V1_ALWAYS_HPP
   2 #define BOOST_METAPARSE_V1_ALWAYS_HPP
   3
   4 // Copyright Abel Sinkovics (abel@sinkovics.hu)  2009 - 2010.
   5 // Distributed under the Boost Software License, Version 1.0.
   6 //    (See accompanying file LICENSE_1_0.txt or copy at
   7 //          http://www.boost.org/LICENSE_1_0.txt)
   8
   9 #include <boost/metaparse/v1/accept.hpp>
  10 #include <boost/metaparse/v1/is_error.hpp>
  11 #include <boost/metaparse/v1/get_remaining.hpp>
  12 #include <boost/metaparse/v1/get_position.hpp>
  13
  14 #include <boost/mpl/eval_if.hpp>
  15
  16 namespace boost
  17 {
  18   namespace metaparse
  19   {
  20     namespace v1
  21     {
  22       template <class P, class Result>
  23       struct always
  24       {
  25       private:
  26         template <class Res>
  27         struct apply_unchecked :
  28           accept<
  29             Result,
  30             typename get_remaining<Res>::type,
  31             typename get_position<Res>::type
  32           >
  33         {};
  34       public:
  35         typedef always type;
  36
  37         template <class S, class Pos>
  38         struct apply :
  39           boost::mpl::eval_if<
  40             typename is_error<typename P::template apply<S, Pos> >::type,
  41             typename P::template apply<S, Pos>,
  42             apply_unchecked<typename P::template apply<S, Pos> >
  43           >
  44         {};
  45       };
  46     }
  47   }
  48 }
  49
  50 #endif
  51