1 files changed, 4 insertions, 0 deletions

diff --git a/src/stackindex.hpp b/src/stackindex.hpp
index 1c2ce8c..c414ce2 100644
--- a/src/stackindex.hpp
+++ b/src/stackindex.hpp
@@ -5,6 +5,9 @@
 DECLARE_UNIQUE_TYPE(StackIndex, int);
 static_assert(std::is_trivial_v<StackIndex>);
 
+DECLARE_UNIQUE_TYPE(UserValueIndex, int);
+static_assert(std::is_trivial_v<UserValueIndex>);
+
 DECLARE_UNIQUE_TYPE(UserValueCount, int);
 static_assert(std::is_trivial_v<UserValueCount>);
 
@@ -14,4 +17,5 @@ static_assert(std::is_trivial_v<UserValueCount>);
 // #################################################################################################
 
 static constexpr StackIndex kIdxRegistry{ LUA_REGISTRYINDEX };
+static constexpr StackIndex kIdxNone{ 0 };
 static constexpr StackIndex kIdxTop{ -1 };