[PaulDavisThe1st]

> It implements message-based programming, which is "real" OOP

No, it's message-based programming, which is a very powerful and useful tool. It's not the one true inheritor of the fundamental OOP concept.

OOP wasn't defined by "you send messages to objects", it was defined by the idea that objects had their own semantics which in turn constrained/defined the things you could do with them. Some OOP languages implemented "doing something to an object" as "send it a message"; some didn't.

ObjC is in the former group; C++ is in the latter.

[mpweiher]

Well, considering that Alan Kay coined the term...

[zepto]

Absolutely incorrect: http://wiki.c2.com/?AlanKayOnMessaging

[PaulDavisThe1st]

Alan Kay didn't invent object oriented programming though he was instrumental in expanding its scope and usage. Simula 67 was a big influence on Kay's work, and as he has noted, the "revelation" that "it's all messages" was a huge one.

But Smalltalk is just one OOP language, not the only one and not even the original one (though we could argue about how much Simula was or was not OOP, and I'd rather not).

The message from Kay you cite about is strictly about Smalltalk & Squeak:

> The big idea is "messaging" - that is what the kernal of Smalltalk/Squeak is all about

He doesn't say "what OOP is all about".

[zepto]

Actually he did invent Object Oriented programming.

Simula was an inspiration, but was never considered as object oriented. After Kay came up with the concept, Simula was identified as part of the historical background.

“I invented the term object oriented, and I can tell you that C++ wasn't what I had in mind.” —Alan Kay.

[PaulDavisThe1st]

Dahl & Nygard would not agree with you:

https://www.sciencedirect.com/science/article/pii/S089054011...

http://kristennygaard.org/FORSKNINGSDOK_MAPPE/F_OO_start.htm...

Kay came up with the term "object oriented programming", but he has made it very clear that what he had in mind has little relationship to what most people mean by that term today.

If you want to give Kay veto power over the correct application of the term, be my guest but please be consistent across all other cases where a word or phrase changes its meaning over time.

Contemporary OOP pays only lip service to Kay's ideas (something he would be the first to say), and is only tangentially influenced by Smalltalk at this point (Objective C probably being one of the few widely used counterpoints to that).

[zepto]

Those links don’t support your claim about Dahl and Nygard.

They are retrospectives written by other people talking about their work. Not papers by Dahl and Nygard themselves.

Just because you can find some people who are making the same retrospective mistake you are, doesn’t change the history.

OOP was defined by message passing.

What you are calling ‘contemporary OOP’ is a cargo cult based on a failure to appreciate that. The problems with this are increasingly acknowledged.

If you want to say OOP is class based programming, be my guest, but your statements about the history that I responded to are simply false.

[PaulDavisThe1st]

The second link is titled:

> How Object-Oriented Programming Started > > by Ole-Johan Dahl and Kristen Nygaard, > Dept. of Informatics, University of Oslo

The first link is "based on an invited talk" given by the author at the Dept. of Informatics, University of Oslo, with colleagues of (then-deceased) Dahl and Nygaard in attendance. That doesn't guarantee anything in particular, but it makes it likely that they are not making stuff out of thin air.

If OOP was defined by message passing, why was it necessary for Kay to note in 1998 that people had apparently lost sight of this (his) definition?

If you want to say that C++ programming is not OOP, be my guest, but your statements about the history of OOP are not part of some canon or bible.