1 files changed, 63 insertions, 0 deletions
diff --git a/main-window/mixin-traits.hpp b/main-window/mixin-traits.hpp
new file mode 100644
index 00000000..e7d02c85
--- /dev/null
+++ b/main-window/mixin-traits.hpp
@@ -0,0 +1,63 @@
+#pragma once
+
+#include "compat/linkage-macros.hpp"
+#include "compat/macros.hpp"
+#include "compat/meta.hpp"
+
+#include <type_traits>
+
+namespace mixins::traits_detail {
+
+    using namespace meta;
+    template<typename... xs>
+    using tuple = meta::detail::tuple<xs...>;
+
+    template<typename t>
+    struct mixin_traits {
+        using depends = tuple<>;
+    };
+
+    template<typename klass, typename...> struct check_depends_;
+
+    template<typename klass>
+    struct check_depends_<klass>
+    {
+        static constexpr bool recurse() { return true; }
+    };
+
+    template<typename klass, typename x, typename... xs>
+    struct check_depends_<klass, x, xs...>
+    {
+        static constexpr bool recurse()
+        {
+            using depends = typename mixin_traits<x>::depends;
+
+            return (std::is_base_of_v<x, klass> || std::is_same_v<x, klass>) &&
+                   check_depends_<klass, xs...>::recurse() &&
+                   lift<check_depends_, cons<klass, depends>>::recurse();
+        }
+    };
+
+#if 0
+    template<typename final_class, typename t>
+    static constexpr void check_depends_recursively()
+    {
+        std::is_base_of_v<x, final_class> &&
+                           assert_depends<final_class, xs...>::check_depends()
+
+        using depends = typename mixin_traits<t>::depends;
+        static_assert(lift<assert_depends, cons<t, depends>>::check_depends());
+
+        using car = first<depends>;
+        using cdr = rest<depends>;
+
+        check_depends_recursively<car>();
+    }
+#endif
+
+    template<typename t>
+    class impl
+    {
+        static_assert(lift<check_depends_, cons<t, typename mixin_traits<t>::depends>>::recurse());
+    };
+} // ns mixins::traits_detail