ceph/src/boost/boost/bimap/relation/member_at.hpp

   1 // Boost.Bimap
   2 //
   3 // Copyright (c) 2006-2007 Matias Capeletto
   4 //
   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 /// \file relation/member_at.hpp
  10 /// \brief Defines the tags for the member_at::side idiom
  11
  12 #ifndef BOOST_BIMAP_RELATION_MEMBER_AT_HPP
  13 #define BOOST_BIMAP_RELATION_MEMBER_AT_HPP
  14
  15 #if defined(_MSC_VER)
  16 #pragma once
  17 #endif
  18
  19 #include <boost/config.hpp>
  20
  21 namespace boost {
  22 namespace bimaps {
  23 namespace relation {
  24
  25 /// \brief member_at::side idiom to access relation values and types using metaprogramming.
  26 /**
  27
  28 This tags are used to specify which member you want to acces when using a metafunction over
  29 a symmetrical type. The idea is to be able to write code like:
  30
  31 \code
  32 result_of::get<member_at::left,relation>::type data = get<member_at::left>(rel);
  33 \endcode
  34
  35 The relation class supports this idiom even when the elements are tagged. This is useful
  36 because a user can decide to start tagging in any moment of the development.
  37
  38 See also member_with_tag, is_tag_of_member_at_left, is_tag_of_member_at_right, get
  39 value_type_of, pair_by, pair_type_by.
  40
  41 \ingroup relation_group
  42                                                                                         **/
  43 namespace member_at {
  44
  45     /// \brief Member at left tag
  46     /**
  47     See also member_at, rigth.
  48                                             **/
  49
  50     struct left  {};
  51
  52     /// \brief Member at right tag
  53     /**
  54     See also member_at, left.
  55                                             **/
  56
  57     struct right {};
  58
  59     /// \brief Member info tag
  60     /**
  61     See also member_at, left, right.
  62                                             **/
  63
  64     struct info  {};
  65
  66 }
  67
  68 } // namespace relation
  69 } // namespace bimaps
  70 } // namespace boost
  71
  72 #endif // BOOST_BIMAP_RELATION_MEMBER_AT_HPP