[libcxx] r287981 - Implement the 'detection idiom' from LFTS v2
Marshall Clow via cfe-commits
cfe-commits at lists.llvm.org
Sat Nov 26 07:49:40 PST 2016
Author: marshall
Date: Sat Nov 26 09:49:40 2016
New Revision: 287981
URL: http://llvm.org/viewvc/llvm-project?rev=287981&view=rev
Log:
Implement the 'detection idiom' from LFTS v2
Added:
libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/
libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp
libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp
libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp
libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp
libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp
Modified:
libcxx/trunk/include/experimental/type_traits
Modified: libcxx/trunk/include/experimental/type_traits
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/experimental/type_traits?rev=287981&r1=287980&r2=287981&view=diff
==============================================================================
--- libcxx/trunk/include/experimental/type_traits (original)
+++ libcxx/trunk/include/experimental/type_traits Sat Nov 26 09:49:40 2016
@@ -172,6 +172,45 @@ inline namespace fundamentals_v1 {
template <class T>
using raw_invocation_type_t = typename raw_invocation_type<T>::type;
+ // 3.3.3, Logical operator traits
+ template<class... B> struct conjunction;
+ template<class... B> constexpr bool conjunction_v = conjunction<B...>::value;
+ template<class... B> struct disjunction;
+ template<class... B> constexpr bool disjunction_v = disjunction<B...>::value;
+ template<class B> struct negation;
+ template<class B> constexpr bool negation_v = negation<B>::value;
+
+ // 3.3.4, Detection idiom
+ template <class...> using void_t = void;
+
+ struct nonesuch {
+ nonesuch() = delete;
+ ~nonesuch() = delete;
+ nonesuch(nonesuch const&) = delete;
+ void operator=(nonesuch const&) = delete;
+ };
+
+ template <template<class...> class Op, class... Args>
+ using is_detected = see below;
+ template <template<class...> class Op, class... Args>
+ constexpr bool is_detected_v = is_detected<Op, Args...>::value;
+ template <template<class...> class Op, class... Args>
+ using detected_t = see below;
+ template <class Default, template<class...> class Op, class... Args>
+ using detected_or = see below;
+ template <class Default, template<class...> class Op, class... Args>
+ using detected_or_t = typename detected_or<Default, Op, Args...>::type;
+ template <class Expected, template<class...> class Op, class... Args>
+ using is_detected_exact = is_same<Expected, detected_t<Op, Args...>>;
+ template <class Expected, template<class...> class Op, class... Args>
+ constexpr bool is_detected_exact_v
+ = is_detected_exact<Expected, Op, Args...>::value;
+ template <class To, template<class...> class Op, class... Args>
+ using is_detected_convertible = is_convertible<detected_t<Op, Args...>, To>;
+ template <class To, template<class...> class Op, class... Args>
+ constexpr bool is_detected_convertible_v
+ = is_detected_convertible<To, Op, Args...>::value;
+
} // namespace fundamentals_v1
} // namespace experimental
} // namespace std
@@ -420,6 +459,52 @@ template <class _Tp>
using raw_invocation_type_t = typename raw_invocation_type<_Tp>::type;
*/
+// 3.3.4, Detection idiom
+template <class...> using void_t = void;
+
+struct nonesuch {
+ nonesuch() = delete;
+ ~nonesuch() = delete;
+ nonesuch (nonesuch const&) = delete;
+ void operator=(nonesuch const&) = delete;
+ };
+
+template <class _Default, class _AlwaysVoid, template <class...> class _Op, class... _Args>
+struct _DETECTOR {
+ using value_t = false_type;
+ using type = _Default;
+ };
+
+template <class _Default, template <class...> class _Op, class... _Args>
+struct _DETECTOR<_Default, void_t<_Op<_Args...>>, _Op, _Args...> {
+ using value_t = true_type;
+ using type = _Op<_Args...>;
+ };
+
+
+template <template<class...> class _Op, class... _Args>
+ using is_detected = typename _DETECTOR<nonesuch, void, _Op, _Args...>::value_t;
+template <template<class...> class _Op, class... _Args>
+ using detected_t = typename _DETECTOR<nonesuch, void, _Op, _Args...>::type;
+template <template<class...> class _Op, class... _Args>
+ _LIBCPP_CONSTEXPR bool is_detected_v = is_detected<_Op, _Args...>::value;
+
+template <class Default, template<class...> class _Op, class... _Args>
+ using detected_or = _DETECTOR<Default, void, _Op, _Args...>;
+template <class Default, template<class...> class _Op, class... _Args>
+ using detected_or_t = typename detected_or<Default, _Op, _Args...>::type;
+
+template <class Expected, template<class...> class _Op, class... _Args>
+ using is_detected_exact = is_same<Expected, detected_t<_Op, _Args...>>;
+template <class Expected, template<class...> class _Op, class... _Args>
+ _LIBCPP_CONSTEXPR bool is_detected_exact_v = is_detected_exact<Expected, _Op, _Args...>::value;
+
+template <class To, template<class...> class _Op, class... _Args>
+ using is_detected_convertible = is_convertible<detected_t<_Op, _Args...>, To>;
+template <class To, template<class...> class _Op, class... _Args>
+ _LIBCPP_CONSTEXPR bool is_detected_convertible_v = is_detected_convertible<To, _Op, _Args...>::value;
+
+
_LIBCPP_END_NAMESPACE_LFTS
#endif /* _LIBCPP_STD_VER > 11 */
Added: libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp?rev=287981&view=auto
==============================================================================
--- libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp (added)
+++ libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_or.pass.cpp Sat Nov 26 09:49:40 2016
@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+// <experimental/type_traits>
+
+#include <experimental/type_traits>
+#include <string>
+
+#include "test_macros.h"
+
+namespace ex = std::experimental;
+
+template <typename T>
+ using hasFoo = typename T::Foo;
+
+struct yesFoo {
+ using Foo = int;
+};
+
+struct noFoo {
+};
+
+
+template <typename T, typename Res>
+void test() {
+ static_assert( std::is_same<Res, typename ex::detected_or <double, hasFoo, T>::type>::value, "" );
+ static_assert( std::is_same<Res, typename ex::detected_or_t<double, hasFoo, T> >::value, "" );
+}
+
+int main () {
+ test<yesFoo, int>();
+ test<noFoo, double>();
+}
Added: libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp?rev=287981&view=auto
==============================================================================
--- libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp (added)
+++ libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/detected_t.pass.cpp Sat Nov 26 09:49:40 2016
@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+// <experimental/type_traits>
+
+#include <experimental/type_traits>
+#include <string>
+
+#include "test_macros.h"
+
+namespace ex = std::experimental;
+
+template <typename T>
+ using callFoo = decltype(std::declval<T&>().Foo());
+
+struct yesFoo {
+ int Foo() { return 0; }
+};
+
+struct noFoo {
+};
+
+struct wrongFoo {
+ std::string Foo() { return ""; }
+};
+
+struct convertibleFoo {
+ long Foo() { return 0; }
+};
+
+
+template <typename T, typename Res>
+void test() {
+ static_assert( std::is_same<Res, typename ex::detected_t<callFoo, T>>::value, "" );
+}
+
+int main () {
+ test<yesFoo, int>();
+ test<noFoo, ex::nonesuch>(); // lookup failure returns nonesuch
+ test<wrongFoo, std::string>();
+}
Added: libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp?rev=287981&view=auto
==============================================================================
--- libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp (added)
+++ libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected.pass.cpp Sat Nov 26 09:49:40 2016
@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+// <experimental/type_traits>
+
+#include <experimental/type_traits>
+#include <string>
+
+#include "test_macros.h"
+
+namespace ex = std::experimental;
+
+template <typename T>
+ using copy_assign_t = decltype(std::declval<T&>() = std::declval<T const &>());
+
+struct not_assignable {
+ not_assignable & operator=(const not_assignable&) = delete;
+};
+
+template <typename T, bool b>
+void test() {
+ static_assert( b == ex::is_detected <copy_assign_t, T>::value, "" );
+ static_assert( b == ex::is_detected_v<copy_assign_t, T>, "" );
+}
+
+int main () {
+ test<int, true>();
+ test<std::string, true>();
+ test<not_assignable, false>();
+}
Added: libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp?rev=287981&view=auto
==============================================================================
--- libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp (added)
+++ libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_convertible.pass.cpp Sat Nov 26 09:49:40 2016
@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+// <experimental/type_traits>
+
+#include <experimental/type_traits>
+#include <string>
+
+#include "test_macros.h"
+
+namespace ex = std::experimental;
+
+template <typename T>
+ using callFoo = decltype(std::declval<T&>().Foo());
+
+struct yesFoo {
+ int Foo() { return 0; }
+};
+
+struct noFoo {
+};
+
+struct wrongFoo {
+ std::string Foo() { return ""; }
+};
+
+struct convertibleFoo {
+ long Foo() { return 0; }
+};
+
+
+template <typename T, bool b>
+void test() {
+ static_assert( b == ex::is_detected_convertible <int, callFoo, T>::value, "" );
+ static_assert( b == ex::is_detected_convertible_v<int, callFoo, T>, "" );
+}
+
+int main () {
+ test<yesFoo, true>();
+ test<noFoo, false>();
+ test<wrongFoo, false>();
+ test<convertibleFoo, true>();
+}
Added: libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp?rev=287981&view=auto
==============================================================================
--- libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp (added)
+++ libcxx/trunk/test/std/experimental/utilities/meta/meta.detect/is_detected_exact.pass.cpp Sat Nov 26 09:49:40 2016
@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+// <experimental/type_traits>
+
+#include <experimental/type_traits>
+#include <string>
+
+#include "test_macros.h"
+
+namespace ex = std::experimental;
+
+template <typename T>
+ using callFoo = decltype(std::declval<T&>().Foo());
+
+struct yesFoo {
+ int Foo() { return 0; }
+};
+
+struct noFoo {
+};
+
+struct wrongFoo {
+ std::string Foo() { return ""; }
+};
+
+struct convertibleFoo {
+ long Foo() { return 0; }
+};
+
+template <typename T, bool b>
+void test() {
+ static_assert( b == ex::is_detected_exact <int, callFoo, T>::value, "" );
+ static_assert( b == ex::is_detected_exact_v<int, callFoo, T>, "" );
+}
+
+int main () {
+ test<yesFoo, true>();
+ test<noFoo, false>();
+ test<wrongFoo, false>();
+ test<convertibleFoo, false>();
+}
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