They're a kind of advice [1]. Advice was indeed subsumed by CLOS method combination, but existed prior to that and has a life of its own, for example in Aspect

They're a kind of advice [1]. Advice was indeed subsumed by CLOS method combination, but existed prior to that and has a life of its own, for example in Aspect Oriented Programming. [1]: https://en.wikipedia.org/wiki/Advice_(programming) https://en.wikipedia.org/wiki/Advice_(programming) [2]: https://en.wikipedia.org/wiki/Aspect-oriented_programming https://en.wikipedia.org/wiki/Aspect-oriented_programming