....so.....exactly no sophisticated project (except something like tex, maybe) can meet this requirement under all circumstances, let alone a nle.
Even something written in "safe languages" like haskell or prolog are at the whims of their interpreters.
However, you later say "more or less", so obviously that requirement isn't as hard as you said in the beginning
Don't take my first post so literally. I exaggerated to make a point.