add trackbar 'sub-consumer' for value label refresh when 'change-on-release'

src/logic/scripting/scripting_functional.hpp

@@ -72,6 +72,12 @@ namespace scripting {
         const std::string& src, 
         const std::string& file="<string>"
     );
+
+    dynamic::to_string_func create_tostring(
+        const scriptenv& env,
+        const std::string& src,
+        const std::string& file="<string>"
+    );
 }
 
 #endif // LOGIC_SCRIPTING_SCRIPTING_FUNCTIONAL_HPP_