ceph/src/boost/libs/spirit/include/boost/spirit/home/qi/reference.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7 #if !defined(BOOST_SPIRIT_REFERENCE_OCTOBER_31_2008_1218AM)
   8 #define BOOST_SPIRIT_REFERENCE_OCTOBER_31_2008_1218AM
   9
  10 #if defined(_MSC_VER)
  11 #pragma once
  12 #endif
  13
  14 #include <boost/spirit/home/qi/meta_compiler.hpp>
  15 #include <boost/spirit/home/qi/parser.hpp>
  16 #include <boost/spirit/home/support/info.hpp>
  17 #include <boost/spirit/home/support/handles_container.hpp>
  18 #include <boost/type_traits/remove_const.hpp>
  19 #include <boost/ref.hpp>
  20
  21 namespace boost { namespace spirit { namespace qi
  22 {
  23     ///////////////////////////////////////////////////////////////////////////
  24     // reference is a parser that references another parser (its Subject)
  25     ///////////////////////////////////////////////////////////////////////////
  26     template <typename Subject>
  27     struct reference : parser<reference<Subject> >
  28     {
  29         typedef Subject subject_type;
  30
  31         reference(Subject& subject)
  32           : ref(subject) {}
  33
  34         template <typename Context, typename Iterator>
  35         struct attribute : Subject::template attribute<Context, Iterator> {};
  36
  37         template <typename Iterator, typename Context
  38           , typename Skipper, typename Attribute>
  39         bool parse(Iterator& first, Iterator const& last
  40           , Context& context, Skipper const& skipper
  41           , Attribute& attr_) const
  42         {
  43             return ref.get().parse(first, last, context, skipper, attr_);
  44         }
  45
  46         template <typename Context>
  47         info what(Context& context) const
  48         {
  49             // the reference is transparent (does not add any info)
  50             return ref.get().what(context);
  51         }
  52
  53         boost::reference_wrapper<Subject> ref;
  54     };
  55 }}}
  56
  57 namespace boost { namespace spirit { namespace traits
  58 {
  59     ///////////////////////////////////////////////////////////////////////////
  60     template <typename Subject, typename Attribute, typename Context
  61       , typename Iterator>
  62     struct handles_container<qi::reference<Subject>, Attribute, Context
  63       , Iterator>
  64       : handles_container<typename remove_const<Subject>::type
  65         , Attribute, Context, Iterator>
  66     {};
  67 }}}
  68
  69 #endif