[bunderbunder]

That speaks to one of the things that bothers me about OOP's intellectual traditions: there are two different ideas of what "object" can mean, and most object-oriented languages and practices deeply conflate the two.

On the one hand, "object" can mean a unification of data structures with the procedures that act on them. In this view, the ideal is for everything to be an "object", and for all the procedures to actually be methods of some class. This is the place from which we get both the motivation for Java's ban on functions that don't belong to classes, and the criticism of Java as not being truly OO because not every type is an object. In this view, Erlang is not OO, since, at the root, functions are separate from datatypes.

On the other hand, "object" can describe a certain approach to modularity, where the modules are relatively isolated entities that are supposed to behave like black boxes that can only communicate by passing some sort of message back and forth. This ends up being the motivation for Java's practice of making all fields private, and only communicating with them through method calls. In this view, Erlang is extremely OO, for all the reasons described in parent.

I haven't done an exhaustive analysis or anything, but I'm beginning to suspect that most the woes that critics commonly describe about OO come from the conflation of these two distinct ideas.

[convolvatron]

dont forget inheritance. its either orthogonal or essential to what it means to be 'object oriented' depending on who you are talking to.

[bunderbunder]

I haven't, but, at least insofar as my thinking has developed (and insofar as Erlang supports it), the question of inheritance is more orthogonal than essential to the specific point I was trying to make. And failed to state clearly, so here it is: This essay is right, and Armstrong is also right when he said "Erlang might be the only object-oriented language". The tension there isn't, at the root, because Armstrong was confused about what OOP is really about; it's because OOP itself was (and is) confused about what OOP is really about.

That said, I would also argue that, like "object", "inheritance" is a word that can describe many distinct concepts, that and here, too, OOP's intellectual traditions create a muddle by conflating them.

[reallydude]

> dont forget inheritance

Inheritance is a limited convention to do mixins. Including it in the abstract idea of object oriented programming is harmful, other than in reference to the ugly history of "Classical OOP" or "Non-Kay OOP" as you like.