From d42eb123775b5ed627a41adedfce4f582cc27acc Mon Sep 17 00:00:00 2001
From: Patrick Wuttke <p.wuttke@dsfishlabs.com>
Date: Tue, 17 Feb 2026 10:25:09 +0100
Subject: [PATCH] Added variant_index utility trait.

---
 source/mijin/util/variant.hpp | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/source/mijin/util/variant.hpp b/source/mijin/util/variant.hpp
index a3a98d5..da21699 100644
--- a/source/mijin/util/variant.hpp
+++ b/source/mijin/util/variant.hpp
@@ -20,6 +20,29 @@ inline constexpr bool variant_contains_v = false;
 template<typename TSearch, typename... TVariantTypes>
 inline constexpr bool variant_contains_v<TSearch, std::variant<TVariantTypes...>> = mijin::is_any_type_v<TSearch, TVariantTypes...>;
 
+
+template<typename TSearch, typename TVariant>
+struct variant_index;
+
+template<typename TSearch, typename TFirst, typename... TVariantTypes>
+struct variant_index<TSearch, std::variant<TFirst, TVariantTypes...>>
+{
+    static constexpr std::size_t getValue() noexcept
+    {
+        if constexpr (std::is_same_v<TSearch, TFirst>) {
+            return 0;
+        }
+        else {
+            return variant_index<TSearch, std::variant<TVariantTypes...>>::getValue() + 1;
+        }
+    }
+
+    static constexpr std::size_t value = getValue();
+};
+
+template<typename TSearch, typename TVariant>
+inline constexpr std::size_t variant_index_v = variant_index<TSearch, TVariant>::value;
+
 //
 // public types
 //