Right, I don't really disagree with you, I think. It's just that I associate "pattern" with things that are "done by convention". By contrast the state monad

Right, I don't really disagree with you, I think. It's just that I associate "pattern" with things that are "done by convention". By contrast the state monad is encoded in the language in Haskell rather than just "done by convention". On the other hand, I would say that your state monad in Python is a pattern, because there's no way of expressing the structure of the state monad in Python.