added delete callback to const_list_node

include/const_list.h

@@ -6,6 +6,7 @@
 #define UDIFF_CONST_LIST_H_
 
 #include <concepts>
+#include <functional>
 #include <initializer_list>
 #include <iterator>
 
@@ -213,10 +214,17 @@ namespace cc {
 			const_list_node *_next = nullptr;
 			const_list<D> *_owner = nullptr;
 			
+			void (*_delete_cb)() = nullptr;
+
 		public:
 			constexpr const_list_node() noexcept { asserts(); }
             virtual constexpr ~const_list_node();
 			
+			constexpr void on_delete(void (*cb)());
+		
+		private:
+			void notify_delete();
+			
 			friend class const_list<D>;
 			friend class _const_list_iterator_base<D>;
 	};
@@ -320,9 +328,24 @@ namespace cc {
 	template<typename D>
     constexpr const_list_node<D>::~const_list_node()
 	{
+		if (_delete_cb) 
+			(*_delete_cb)();
         _owner->remove(*this);
     }
 
+	template<typename D>
+	constexpr void const_list_node<D>::on_delete(void (*cb)())
+	{
+		_delete_cb = cb;
+	}
+
+	template<typename D>
+	void const_list_node<D>::notify_delete()
+	{
+		if (_delete_cb)
+			(*_delete_cb)();
+	}
+
 } // cc
 
 #endif //UDIFF_CONST_LIST_H_