Squashed 'externals/mcl/' content from commit a86a53843

git-subtree-dir: externals/mcl
git-subtree-split: a86a53843f82e4d6ca2f2e1437824495acad2712

include/mcl/iterator/reverse.hpp

@@ -0,0 +1,34 @@
+// This file is part of the mcl project.
+// Copyright (c) 2022 merryhime
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <iterator>
+
+namespace mcl::iterator {
+namespace detail {
+
+template<typename T>
+struct reverse_adapter {
+    T& iterable;
+
+    constexpr auto begin() {
+        using namespace std;
+        return rbegin(iterable);
+    }
+
+    constexpr auto end() {
+        using namespace std;
+        return rend(iterable);
+    }
+};
+
+}  // namespace detail
+
+template<typename T>
+constexpr detail::reverse_adapter<T> reverse(T&& iterable) {
+    return detail::reverse_adapter<T>{iterable};
+}
+
+}  // namespace mcl::iterator