stabilize build system: depends, installer, boost/bdb fixes, cross targets groundwork

2026-02-24 18:38:47 +00:00
parent da8c28aaeb
commit 65cb2619a7
13106 changed files with 2484322 additions and 1804 deletions
@@ -0,0 +1,40 @@
+/*!
+@file
+Defines `boost::hana::detail::variadic::at`.
+
+@copyright Louis Dionne 2013-2017
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#ifndef BOOST_HANA_DETAIL_VARIADIC_AT_HPP
+#define BOOST_HANA_DETAIL_VARIADIC_AT_HPP
+
+#include <boost/hana/config.hpp>
+
+#include <cstddef>
+#include <utility>
+
+
+BOOST_HANA_NAMESPACE_BEGIN namespace detail { namespace variadic {
+    template <std::size_t n, typename = std::make_index_sequence<n>>
+    struct at_type;
+
+    template <std::size_t n, std::size_t ...ignore>
+    struct at_type<n, std::index_sequence<ignore...>> {
+    private:
+        template <typename Nth>
+        static constexpr auto go(decltype(ignore, (void*)0)..., Nth nth, ...)
+        { return nth; }
+
+    public:
+        template <typename ...Xs>
+        constexpr auto operator()(Xs ...xs) const
+        { return *go(&xs...); }
+    };
+
+    template <std::size_t n>
+    constexpr at_type<n> at{};
+}} BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_DETAIL_VARIADIC_AT_HPP