Message passing rather than object orientation

Ken Kahn kenkahn at toontalk.com
Thu Oct 11 18:53:35 UTC 2001


Andres Valloud  wrote:

> However, what I find very interesting is that we say "In a
> Smalltalk system everything is an object, and everything gets done when
> objects send messages".  IMHO, that everything is an object is
> insignificant when compared to the requirement that everything gets done
> by sending messages.
>

I think this is a GREAT insight. In my paper, "Objects - A Fresh Look",
ECOOP '89
http://www.ifs.uni-linz.ac.at/~ecoop/cd/papers/ec89/ec890207.pdf
I tried to argue for a much more expanded notion of objects but what I know
releasize is that I was really writing about was more general message
passing. You send a message and maybe an object generates a reply but maybe
several objects receive the message and collaboratively or competively
compute a reply. And a reply might be a single message or a stream of them.
And maybe after an object gets a message it changes into another kind of
object or maybe into a cloud of objects. And maybe an object has more than
one "mail box" where messages arrive. And so on.

A real classic on this topic is Carl Hewitt's "Viewing control structures as
patterns of passing messages", Artificial Intelligence 8 (1977).

Best,

-ken kahn ( www.toontalk.com )





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