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Comment by klibertp | Hacker News Reader

Actually, Erlang and Elixir are one of the most OO languages out there. The original definition of OO, by Alan Kay, was to have a lot of miniature computers, with state and computation ability, called objects, which communicate by sending messages to each other. Yes, calling a method in Smalltalk or Self is called a "message send". Now, take a look at Erlangs processes - doesn't it all sound very similar?

Edited to add: Kay also frequently says he's a proponent of object oriented, not class oriented programming. Classes are just a means of organizing the code, objects and their relationships is what matters. In that way, modules in Elixir are not inferior to classes in single-inheritance OO languages: they offer the same level of sharing and composing code (via macros, defoverridable, and defdelegate). Add to it protocols, which can extend arbitrary types (modules) and you get quite nice OO toolbox to use in Elixir.

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My understanding is that Alan Kay cannot reasonably claim to have "the original definition of OO", only "a very good early definition". Additionally, it seems like he's either been a bit inconsistent or unclear about the essential ideas at different times.

One source: https://hillelwayne.com/post/alan-kay/

Alan Kay provided the first definition of OOP. That is not the same as using the word “object” for the first time.

As that article clearly shows, at least once you’re past its clickbait title, Kay acknowledges his influences. That isn’t a lack of clarity, it’s an awareness that we all build on the effort of our peers and predecessors, that ideas do not spring forth fully formed from the void.

This does not discredit anyone’s work, far from it; context is an aid to understanding.

I could probably have been more specific.

What I mean by lack of clarity is that Kay in 1998 thinks that messaging is the key idea, and suggests that was always the key idea. But none of the historical sources I've seen suggest he was clearly and consistently saying that in the 70s.

That's really a minor point, it does nothing to invalidate Kay's contributions. You can design a system that has value, and only later find the best way to talk about its value. That happens constantly: people create something and then end up saying "in hindsight, I got X right and Y wrong" or "back then, I knew this worked, but it was only later that I knew why".

It doesn't disprove the idea that focusing on messaging gives you the best version of OOP. It doesn't even disprove that "real" OOP is about messaging (though I think that argument has a high bar to clear--most terms are messy).

What it does disprove is that messaging has a right to be the core of OOP because Alan Kay defined it that way back in the 70s.

P.S. Maybe the title isn't ideal, but Hillel was literally reacting to someone who said Alan Kay invented objects: https://lobste.rs/s/8yohqt/alan_kay_oo_programming#c_5xo7on. Actually, that might be a better source than what I linked to, because it marshals more evidence that Kay was not consistently saying "messaging is what matters" during the 70s. He may have believed it, he may have said it sometimes, but he wasn't consistent about it.

Again, that's not a criticism of Kay, except the super mild one that his 90s/2000s memory of what he said 20 years earlier wasn't perfect. But I forget shit I said last week, so I'm not gonna judge.

> disprove ... that messaging has a right

Well, I think "messaging" is an abstract concept. It doesn't have rights, so there was nothing to prove.

Nevertheless, credit matters, because people matter, and do have rights. One of those rights is to have an opinion, including the opinion that messaging is the core of OOP.

> clearly and consistently saying that in the 70s

This is indeed a preposterous and unhealthy standard to expect of anyone, on any topic. It's the kind of thing that two-bit politicians like to dig up on each other, to nobody's edification.

> "messaging" is an abstract concept. It doesn't have rights

We agree. No idea how I screwed up that sentence. The intent was "that messaging is the right core of OOP because", but it was awkward, and I spliced something together.

> It's the kind of thing that two-bit politicians like to dig up on each other, to nobody's edification.

This is a discussion of what a word means, not an attack on someone's character.

Good read, thanks. I knew about Simula, but never analysed it deep enough to know how much of an effect it had on early Smalltalk.

Still, the definition Kay gave as late as in 1998 resonates with me the most:

OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things.

And this is almost exactly what Erlang implements: just add "asynchronous" before "messaging" and it fits perfectly.

Alan has commented a number of times on a number of threads on HN on this....

you can find his various comments here: https://news.ycombinator.com/threads?id=alankay

I've seen his account. I'm not sure I've read every comment, however. Is there one in particular that you think says something not covered in the two pieces I've linked in this thread?

Simula(67) definitely was the original concept/implementation of OO. Smalltalk, C++, Java, etc all derived different aspects of it.

- Main abstraction are classes (of objects).

- Concept of self-initializing data/procedure objects Internal ("concrete") view of an object vs an external ("abstract")

- Differentiated between object instances and the class

- Class/subclass facility made it possible to define generalized object classes, which could be specialized by defining subclasses containing additional declared properties

- Different subclasses could contain different virtual procedure declarations

- Domain specific language dialects

Note Java is actually explicitly based on Objective-C, not on Simula or C++. They just removed most of the Smalltalk bits to make it faster and less scary-looking to C++ programmers.

Hey smt1, looks like your account is dead and has been for a while.

it's clearly not dead.

Actually, it might be. The comment was dead, I vouched for it, so it appeared.

"Object oriented as Alan Kay intended" has been a strapline of Erlang proponents for some time. I think even Joe Armstrong said it once. And I seem to recall Kay speaking approvingly of the quip, and of Erlang itself.

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