Youre being too direct if Im honest! All I was saying is you cant have dynamic constant code, its simply not how C++ works and I see what you want but obviously without access to these other engines I have no idea if it even is possible entirely.
In all honestly Im not fussed about credentials, you clearly know what you want but with so limited information on your use case its actually difficult to provide any sort of solid example. Your question and thought process has been closed before you even posted, thanks for your time.