Oz and Mozart Hackers Mailing List

Re: Proposal for fault detection on ports


From: Donatien Grolaux (ned@info.ucl.ac.be)
Date: Mon Nov 25 2002 - 14:24:50 CET


After seaching for a while, I couldn't figure a case that requires both kinds of sends on the same port. It may be a little bit less convenient, but it's not required, so I'm ok with the PSP (Peter-Seif-Per) proposal.

As for variable bindings, I don't know exactly what should be provided. However in my applications, I often need these operations:

- {BindOrSkip V1 V2} : where V1=V2 either succeeds or is replaced by skip.
- {BindOrDefault V1 V2 D ?R} : where if V1=V2 succeeds, R is bound to V1(==V2), otherwise R is bound to D.
- {BindAndNotify V1 V2 ?N}: tries continuously to V1=V2, and binds ?N to true when it succeeds. This operation can be canceled.

The two first operations are used when giving a free variable to another site as a response channel: let a compute server S and a client C sending a message containing a free variable R for the response. S computes the value requested by C, then BindOrSkip R to that value: it can just skip if C is dead in the meantime. C, when it wants to process the result from S, BindOrDefault R so that it uses a default value if S is dead in the meantime.

Donatien

----- Original Message -----
  From: Peter Van Roy
  Newsgroups: mozart-oz.hackers
  To: hackers@mozart-oz.org
  Sent: Tuesday, November 19, 2002 6:46 PM
  Subject: Re: Proposal for fault detection on ports

  Donatien Grolaux wrote:
>
> If you make the difference between strong and weak sends at the port
> level, then you cannot do both type of sends with the same port.
> However from my experience this is something you want to do in real
> applications. Why do you want to make that difference at the port
> level instead of the send operation level ?

  Can you give a real example of where you want to do this and
  explain why one couldn't do it with two ports?

  --
  Peter Van Roy
  Département d'Ingénierie Informatique
  (Department of Computing Science and Engineering)
  Université catholique de Louvain
  B-1348 Louvain-la-Neuve, Belgium

  Email: pvr@info.ucl.ac.be
  Tel: (+32) (10) 47.83.74
  Mobile: (+32) 485 42 46 77
  Web: http://www.info.ucl.ac.be/people/cvvanroy.html
  Mozart: http://www.mozart-oz.org
  -
  Please send submissions to hackers@mozart-oz.org
  and administriva mail to hackers-request@mozart-oz.org.
  The Mozart Oz web site is at http://www.mozart-oz.org/.

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Please send submissions to hackers@mozart-oz.org
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