Yeah an example of typeclasses being less flexible to me is if what you really want is OOP polymorphism for something like being able to choose what code to run

Yeah an example of typeclasses being less flexible to me is if what you really want is OOP polymorphism for something like being able to choose what code to run based on configuration. Given that you can add objects to your class path at runtime, you can clearly get some extreme flexibility out of a system without clear parallels in typeclass based polymorphism. Obviously this isn't something you'd want to do all the time, but it's an example of something I think about periodically when comparing the two approaches. With typeclasses, polymorphic behavior is driven strictly by the type, and one must follow that thought to it's conclusion to see the difference. Sometimes it's more useful, sometimes not.