Total agreement! OCaml's object system is wonderfully austere. It arises as a pretty natural extension of the more restrained signature subtyping relation---an

Total agreement! OCaml's object system is wonderfully austere. It arises as a pretty natural extension of the more restrained signature subtyping relation---and this helps drive home, as this article also emphasizes, the vital distinction between subclassing and subtyping. That alone means that you'll have a more well-principled and reasonable object system than basically any other one I've ever used. In day-to-day OCaml, I often hear people suggest that one should avoid the object system. The primary things it buys you are access to the row-typing system and class/object constructor hierarchies. It however is a bit slower due to the use of dynamic dispatch (instead of compiling vtables statically to their use site) and can face some inference issues. That said, row types are an incredibly useful type construct (often Haskellers lament the fact that they're missing leading to the creation of things like Ermine and Vinyl). Cautious use of the object system is very exciting!