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Here's my rebuttal of this rebuttal. For the record, I think OOP is wrong in the sense it had some advantage over the procedural programming, but that has since been superseded by functional (and type/category theory) approaches. In some sense, OOP tends to conflate too many concepts into a single one, a class (or an object), to the point where it is harming the clarity of the code. Ad objection #1: The post doesn't explain, why would you want to model the "natural clustering" of functions on pieces of data, why is not just adding an accidental complexity. Clusters of function and data types do tend to happen, so what? (In fact, they tend to happen differently for functions and data types, which makes encapsulation problematic.) Ad objection #2: This has not been refuted. Ad objection #3: I think this is pretty much a complaint about subtyping polymorphism, which yes tends to be a problem (AFAIK nobody really gave a good semantics to it). For example, a GUI container element needs to define a type of it's elements so it could define how to deal with them. It's difficult to use composition there, because you need to define certain functions on those elements, and many classic OOP languages (Java) do not let you add an interface to an existing class. Parametric polymorphism (and its enhancements like type classes) solves this problem much better, IMHO. Ad objection #4: One of the problems of OOP is that modules also tend to be modeled with classes (see for example public/private access controls). But modules are a third distinct useful category of things, aside from functions and data types. OOP conflates these things into a single entity, an object (or a class). I found in practice, much more useful is to have modules as a separate concept, and explicit import/export controls on the module boundaries. That is, do not tie access controls to functions or data types themselves. This makes modularization easier, because there is an additional layer (module definition) where you can override existing exports and imports. |