StaticValue helper.

Incorporated into `Testing`, for now.  Semi-threadsafe statics,
initialize them before going multithreaded.

Utility/StaticValue.h

@@ -0,0 +1,47 @@
+static_assert( __cplusplus > 201700, "C++17 Required" );
+
+#pragma once
+
+namespace Alepha::Hydrogen::Utility
+{
+	inline namespace exports { inline namespace static_value {} }
+
+	namespace detail::static_value
+	{
+		inline namespace exports {}
+
+		template< typename T >
+		struct default_init
+		{
+			T *operator()() const { return new T{}; }
+		};
+
+		namespace exports
+		{
+			template< typename T, typename Init= default_init< T > >
+			struct StaticValue;
+		}
+
+		template< typename T, typename Init >
+		struct exports::StaticValue
+		{
+			private:
+				T *storage= nullptr;
+
+			public:
+				decltype( auto )
+				get()
+				{
+					if( not storage ) storage= Init{}();
+					return *storage;
+				}
+
+				decltype( auto ) operator ()() { return get(); }
+		};
+	}
+
+	namespace exports::static_value
+	{
+		using namespace detail::static_value::exports;
+	}
+}