libstdc++-v3/include/tr2/type_traits

   1 // TR2 <type_traits> -*- C++ -*-
   2
   3 // Copyright (C) 2011-2014 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /** @file tr2/type_traits
  26  *  This is a TR2 C++ Library header.
  27  */
  28
  29 #ifndef _GLIBCXX_TR2_TYPE_TRAITS
  30 #define _GLIBCXX_TR2_TYPE_TRAITS 1
  31
  32 #pragma GCC system_header
  33 #include <type_traits>
  34 #include <bits/c++config.h>
  35
  36 namespace std _GLIBCXX_VISIBILITY(default)
  37 {
  38 namespace tr2
  39 {
  40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  41
  42   /**
  43    * @addtogroup metaprogramming
  44    * @{
  45    */
  46
  47   /**
  48    *  See N2965: Type traits and base classes
  49    *  by Michael Spertus
  50    */
  51
  52   /**
  53    *  Simple typelist. Compile-time list of types.
  54    */
  55   template<typename... _Elements>
  56     struct __reflection_typelist;
  57
  58   /// Specialization for an empty typelist.
  59   template<>
  60     struct __reflection_typelist<>
  61     {
  62       typedef std::true_type                                    empty;
  63     };
  64
  65   /// Partial specialization.
  66   template<typename _First, typename... _Rest>
  67     struct __reflection_typelist<_First, _Rest...>
  68     {
  69       typedef std::false_type                                   empty;
  70
  71       struct first
  72       {
  73         typedef _First                                          type;
  74       };
  75
  76       struct rest
  77       {
  78         typedef __reflection_typelist<_Rest...>                 type;
  79       };
  80     };
  81
  82   /// Sequence abstraction metafunctions for manipulating a typelist.
  83
  84
  85
  86   /// Enumerate all the base classes of a class. Form of a typelist.
  87   template<typename _Tp>
  88     struct bases
  89     {
  90       typedef __reflection_typelist<__bases(_Tp)...>            type;
  91     };
  92
  93   /// Enumerate all the direct base classes of a class. Form of a typelist.
  94   template<typename _Tp>
  95     struct direct_bases
  96     {
  97       typedef __reflection_typelist<__direct_bases(_Tp)...>     type;
  98     };
  99
 100   /// @} group metaprogramming
 101
 102 _GLIBCXX_END_NAMESPACE_VERSION
 103 }
 104 }
 105
 106 #endif // _GLIBCXX_TR2_TYPE_TRAITS