Panel digits seem to be a bit useless outside of Lite-C.
If you want to use ints or floats in C++ you can't do the necessary var conversion.
If you want to use other non-C-compatible languages you often can't pass a variable pointer at all.
My suggestion would be an update callback mechanism for digits. Instead of a var* pointer each digit(slider,...) can optionally get a function pointer. The return value of this function (which gets called every frame) sets the value the digit displays. There should also be a user data parameter which gets passed to the function.
Or maybe someone has a better idea?