Hi there, Is there any interest in library that makes template programming imperative. Basically it provides following API VAR(T); // define a variable T SET(T, Type1); // Assign T = Type1 GET(T); // This macro will be expanded to Type1 SET(T, Type2); // Re-assign T = Type2 GET(T); // This macro will be expanded to Type2 The same idea applies to constexpr variable as well. I.e. it's possible to re-define constexpr variable after initialization, though this functionality is not implemented yet. - Github: https://github.com/Mizuchi/tm - Try it online: https://godbolt.org/z/yfQb4K Thanks, Tianjiao