[jeremiep]

Ah my bad! :)

These look very much like Clojure's protocols and multi-methods.

[junke]

Yes, more like multi-methods, except for standard qualifiers (:around, :before, ...) and user-defined ones. OTOH, Clojure allows you to define a custom dispatch function.

[jeremiep]

Ah yes, Clojure has no first-class support for aspects. Its easy enough to monkey patch definitions for the rare case when its needed.

Most of the time however I try to avoid aspects as they introduce hidden behaviour in existing functions, which can be hard to reason about at scale, especially with more than a few developers.

[junke]

I use them all the time. It's a great way to separate responsibilities.

[jeremiep]

I prefer function composition for that when possible :)

Aspects I feel are more useful when you want to modify the behaviour of existing code you don't own.

Maybe if I had easy access to them I'd find more use cases :)