Thanks for the link to Clojure's polymorphism. I'll need to read through it later and in more detail. Isn't the open/closed principle more of an OOP design con

Thanks for the link to Clojure's polymorphism. I'll need to read through it later and in more detail. Isn't the open/closed principle more of an OOP design concept? In a statically typed language like F#, I want and expect to be notified what functions I need to update when I add a new type constructor to an existing type. This isn't a problem and is welcomed. Just because one updates functions doesn't make them brittle or inextensible. By only adding a new pattern matching branch, one is able to extend a function without affecting the other branches. However, this is getting into the statically typed nature of F#. I think that link explains the expression problem rather superficially. It says you just need to add a new class, but neglects to mention that that also entails adding the new method overrides. So simply saying the OOP way is easy and functional programming is difficult when adding a new type is not really accurate. Same thing for adding a function in the functional programming paradigm, because it neglects you need to add a branch for all types. In reality, OOP inheritance and functional pattern matching are simply transposes of each other, and I'd argue that one is not really necessarily better or worse than the other. They're simply different organizational methods of how the data and functions on the data are organized.