libstdc++

tr2/type_traits
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1 // TR2 <type_traits> -*- C++ -*-
2
3 // Copyright (C) 2011-2013 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