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From: tombre@weissenburger.crin.fr (Karl Tombre)
Newsgroups: comp.object
Subject: Re: "Messaging" (Re: Reentrant code)
Message-ID: <374@loria.crin.fr>
Date: 11 Oct 89 16:48:43 GMT
References: <8636@goofy.megatest.UUCP> <135300001@p.cs.uiuc.edu>
Sender: news@loria.crin.fr
Reply-To: tombre@loria.crin.fr (Karl Tombre)
Organization: CRIN - INRIA Lorraine, Nancy, France
Lines: 25

In article <135300001@p.cs.uiuc.edu> johnson@p.cs.uiuc.edu writes:
>Of course C++ has messages!  There is no essential difference
>between Smalltalk messages and C++ virtual functions.  Although
>their implementation is entirely different, they are used the
>same way.

It is probably better to call this common use "dynamic binding".
The "message sending" vocabulary became popular with Smalltalk.
However, even Smalltalk messages are not that real !!! Think of it: a
Smalltalk message is not an object. And communication remains synchronous:
sending a message blocks the sender until it receives a response.

You can find "real" messages in the actor model (Hewitt, Lieberman,
Agha) or in some other languages, for instance Hybrid from the
University of Geneva. The latter language has both synchronous and
asynchronous communication, i.e. message can be sent in such a way
that it blocks the sender, or it can be put into the mailbox of the
receiver and liberate immediatly the sender.

Once again, didn't we lose something from Simula, which had a "detach"
instruction ?


Karl Tombre - INRIA Lorraine / CRIN
EMAIL : tombre@loria.crin.fr - POST : BP 239, 54506 VANDOEUVRE CEDEX, France