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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: confusion about message passing between the tasks
Date: Sun, 26 Oct 2014 21:42:24 +0100
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Date: 2014-10-26T21:42:24+01:00
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On Sun, 26 Oct 2014 16:27:34 -0400, Robert A Duff wrote:

> "J-P. Rosen" <rosen@adalog.fr> writes:
> 
>> Le 26/10/2014 00:23, Robert A Duff a écrit :
>>> I prefer protected objects.  Less coupling: two tasks can communicate
>>> with each other with neither one knowing the identity of the other --
>>> they both just know about the protected object.
>>> 
>>> If I were redesigning Ada from scratch, I'd leave out rendezvous.
>>> Everything you can do with rendezvous you can do with (something like)
>>> protected objects.
>>
>> ... and everything you can do with structured statements you can do with
>> if and goto.
> 
> OK, then I'll make a stronger claim: Everything you can do with
> rendezvous you can do with (something like) protected objects,
> and do it just as cleanly, and sometimes even better.

You cannot program in a procedural way with PO. You can implement
equivalent semantics, possibly, but not the program structure.

An extreme scenario (unfortunately not Ada's annex E), a distributed system
could be decomposed around rendezvous between tasks running on physically
distributed nodes. This cannot be done with PO.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de