Add logical trait polyfills

1 files changed, 44 insertions, 0 deletions

diff --git a/src/catch2/internal/catch_logical_traits.hpp b/src/catch2/internal/catch_logical_traits.hpp
new file mode 100644
index 00000000..bd875659
--- /dev/null
+++ b/src/catch2/internal/catch_logical_traits.hpp
@@ -0,0 +1,44 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#ifndef CATCH_LOGICAL_TRAITS_HPP_INCLUDED
+#define CATCH_LOGICAL_TRAITS_HPP_INCLUDED
+
+#include <type_traits>
+
+namespace Catch {
+namespace Detail {
+
+#if defined( __cpp_lib_logical_traits ) && __cpp_lib_logical_traits >= 201510
+
+    using std::conjunction;
+    using std::disjunction;
+    using std::negation;
+
+#else
+
+    template <class...> struct conjunction : std::true_type {};
+    template <class B1> struct conjunction<B1> : B1 {};
+    template <class B1, class... Bn>
+    struct conjunction<B1, Bn...>
+        : std::conditional_t<bool( B1::value ), conjunction<Bn...>, B1> {};
+
+    template <class...> struct disjunction : std::false_type {};
+    template <class B1> struct disjunction<B1> : B1 {};
+    template <class B1, class... Bn>
+    struct disjunction<B1, Bn...>
+        : std::conditional_t<bool( B1::value ), B1, disjunction<Bn...>> {};
+
+    template <class B>
+    struct negation : std::integral_constant<bool, !bool(B::value)> {};
+
+#endif
+
+} // namespace Detail
+} // namespace Catch
+
+#endif // CATCH_LOGICAL_TRAITS_HPP_INCLUDED