You could, but then you'd have 'comments' that change the semantics of the program, which is exactly what comments are not supposed to do. The point of adding a

You could, but then you'd have 'comments' that change the semantics of the program, which is exactly what comments are not supposed to do. The point of adding annotations in comments is that environments that don't understand the annotations will ignore them, because they're in comments. It's therefore only a not-horrible idea to add features via comments in situations where the new features actually don't change semantics, such that the program will still produce the same result when run in an environment that doesn't understand the extras.