| > Relying on shapes instead of types to identify results / objects Is the issue lack of types or relying on shapes? Those can be orthogonal features, since you can have structural typing (i.e. types that are built on top of shapes). Nominal typing is often too rigid (and not the direction we are exploring in Elixir's type system). > for example behaviors / protocols should be one implementation instead of two separate ideas Elixir has three building blocks: processes, modules, and data. Message-passing is polymorphism for processes, behaviour is polymorphism for modules, and protocol is polymorphism for data. The overlapping comes that modules in Elixir are first-class (so they can be used as data) and that data (structs) must be defined inside modules. So while maybe those features could feel closer to each other, I don't think they could be one implementation. One idea would be to treat modules/behaviors as "nullary protocols" but that's not what "nullary typeclasses" mean in Haskell, so it is quite debatable. Do you have examples of languages that do both in one implementation? For example, my understanding is that both Haskell and Go offer "protocols" but not "behaviours". I'm not aware of a language with both as one. I'd love to hear other concepts that overlap, it is always good food for thought! |