1 files changed, 15 insertions, 7 deletions

diff --git a/src/unique.hpp b/src/unique.hpp
index aeb7a67..846708e 100644
--- a/src/unique.hpp
+++ b/src/unique.hpp
@@ -3,7 +3,7 @@
 // #################################################################################################
 
 // A unique type generator
-template <typename T, auto = [] {}, typename specialization = void>
+template <typename T, typename TAG, typename specialization = void>
 class Unique
 {
     private:
@@ -11,13 +11,15 @@ class Unique
 
     public:
     using type = T;
-    Unique() = default;
+    constexpr Unique() = default;
     operator T() const { return val; }
-    explicit Unique(T b_)
+    Unique& operator=(T const&) = delete;
+    Unique& operator=(T&&) = delete;
+    explicit constexpr Unique(T b_)
     : val{ b_ }
     {
     }
-    // pre-imcrement
+    // pre-increment
     auto& operator++()
     {
         ++val;
@@ -26,12 +28,12 @@ class Unique
     // post-increment
     auto operator++(int)
     {
-        return Unique<T>{ std::exchange(val, val + 1) };
+        return Unique<T, TAG>{ std::exchange(val, val + 1) };
     }
 };
 
-template <typename T, auto lambda>
-class Unique<T, lambda, std::enable_if_t<!std::is_scalar_v<T>>>
+template <typename T, typename TAG>
+class Unique<T, TAG, std::enable_if_t<!std::is_scalar_v<T>>>
 : public T
 {
     public:
@@ -42,3 +44,9 @@ class Unique<T, lambda, std::enable_if_t<!std::is_scalar_v<T>>>
     {
     }
 };
+
+#define DECLARE_UNIQUE_TYPE(_name, _type) using _name = Unique<_type, class Unique_##_name##_Tag>
+
+// putting this here to break a header circular dependency until I find a better place
+DECLARE_UNIQUE_TYPE(StackIndex, int);
+static constexpr StackIndex kIdxTop{ -1 };