2 //===-------------------------- type_traits -------------------------------===//
4 // The LLVM Compiler Infrastructure
6 // This file is dual licensed under the MIT and the University of Illinois Open
7 // Source Licenses. See LICENSE.TXT for details.
9 //===----------------------------------------------------------------------===//
11 #ifndef _LIBCPP_EXPERIMENTAL_TYPE_TRAITS
12 #define _LIBCPP_EXPERIMENTAL_TYPE_TRAITS
15 experimental/type_traits synopsis
18 #include <type_traits>
21 namespace experimental {
22 inline namespace fundamentals_v1 {
24 // 3.3.2, Other type transformations
25 template <class> class invocation_type; // not defined
26 template <class F, class... ArgTypes> class invocation_type<F(ArgTypes...)>;
27 template <class> class raw_invocation_type; // not defined
28 template <class F, class... ArgTypes> class raw_invocation_type<F(ArgTypes...)>;
31 using invocation_type_t = typename invocation_type<T>::type;
33 using raw_invocation_type_t = typename raw_invocation_type<T>::type;
35 // 3.3.4, Detection idiom
36 template <class...> using void_t = void;
41 nonesuch(nonesuch const&) = delete;
42 void operator=(nonesuch const&) = delete;
45 template <template<class...> class Op, class... Args>
46 using is_detected = see below;
47 template <template<class...> class Op, class... Args>
48 constexpr bool is_detected_v = is_detected<Op, Args...>::value;
49 template <template<class...> class Op, class... Args>
50 using detected_t = see below;
51 template <class Default, template<class...> class Op, class... Args>
52 using detected_or = see below;
53 template <class Default, template<class...> class Op, class... Args>
54 using detected_or_t = typename detected_or<Default, Op, Args...>::type;
55 template <class Expected, template<class...> class Op, class... Args>
56 using is_detected_exact = is_same<Expected, detected_t<Op, Args...>>;
57 template <class Expected, template<class...> class Op, class... Args>
58 constexpr bool is_detected_exact_v
59 = is_detected_exact<Expected, Op, Args...>::value;
60 template <class To, template<class...> class Op, class... Args>
61 using is_detected_convertible = is_convertible<detected_t<Op, Args...>, To>;
62 template <class To, template<class...> class Op, class... Args>
63 constexpr bool is_detected_convertible_v
64 = is_detected_convertible<To, Op, Args...>::value;
66 } // namespace fundamentals_v1
67 } // namespace experimental
72 #include <experimental/__config>
74 #if _LIBCPP_STD_VER > 11
76 #include <type_traits>
78 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
79 #pragma GCC system_header
82 _LIBCPP_BEGIN_NAMESPACE_LFTS
84 // 3.3.2, Other type transformations
87 class _LIBCPP_TEMPLATE_VIS raw_invocation_type;
89 template <class _Fn, class ..._Args>
90 class _LIBCPP_TEMPLATE_VIS raw_invocation_type<_Fn(_Args...)>;
93 class _LIBCPP_TEMPLATE_VIS invokation_type;
95 template <class _Fn, class ..._Args>
96 class _LIBCPP_TEMPLATE_VIS invokation_type<_Fn(_Args...)>;
99 using invokation_type_t = typename invokation_type<_Tp>::type;
102 using raw_invocation_type_t = typename raw_invocation_type<_Tp>::type;
105 // 3.3.4, Detection idiom
106 template <class...> using void_t = void;
110 ~nonesuch() = delete;
111 nonesuch (nonesuch const&) = delete;
112 void operator=(nonesuch const&) = delete;
115 template <class _Default, class _AlwaysVoid, template <class...> class _Op, class... _Args>
117 using value_t = false_type;
118 using type = _Default;
121 template <class _Default, template <class...> class _Op, class... _Args>
122 struct _DETECTOR<_Default, void_t<_Op<_Args...>>, _Op, _Args...> {
123 using value_t = true_type;
124 using type = _Op<_Args...>;
128 template <template<class...> class _Op, class... _Args>
129 using is_detected = typename _DETECTOR<nonesuch, void, _Op, _Args...>::value_t;
130 template <template<class...> class _Op, class... _Args>
131 using detected_t = typename _DETECTOR<nonesuch, void, _Op, _Args...>::type;
132 template <template<class...> class _Op, class... _Args>
133 _LIBCPP_CONSTEXPR bool is_detected_v = is_detected<_Op, _Args...>::value;
135 template <class Default, template<class...> class _Op, class... _Args>
136 using detected_or = _DETECTOR<Default, void, _Op, _Args...>;
137 template <class Default, template<class...> class _Op, class... _Args>
138 using detected_or_t = typename detected_or<Default, _Op, _Args...>::type;
140 template <class Expected, template<class...> class _Op, class... _Args>
141 using is_detected_exact = is_same<Expected, detected_t<_Op, _Args...>>;
142 template <class Expected, template<class...> class _Op, class... _Args>
143 _LIBCPP_CONSTEXPR bool is_detected_exact_v = is_detected_exact<Expected, _Op, _Args...>::value;
145 template <class To, template<class...> class _Op, class... _Args>
146 using is_detected_convertible = is_convertible<detected_t<_Op, _Args...>, To>;
147 template <class To, template<class...> class _Op, class... _Args>
148 _LIBCPP_CONSTEXPR bool is_detected_convertible_v = is_detected_convertible<To, _Op, _Args...>::value;
151 _LIBCPP_END_NAMESPACE_LFTS
153 #endif /* _LIBCPP_STD_VER > 11 */
155 #endif /* _LIBCPP_EXPERIMENTAL_TYPE_TRAITS */