From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: why access parameter in stream attributes to begin with, instead of in or in/out ?
Date: Tue, 12 Jun 2018 10:30:25 +0200
Date: 2018-06-12T10:30:25+02:00 [thread overview]
Message-ID: <pfo0b0$1ii9$1@gioia.aioe.org> (raw)
In-Reply-To: cc1d2271-6057-4a67-a8d9-23344276f707@googlegroups.com
On 2018-06-12 08:28, Mehdi Saada wrote:
> Oh... Understood. In the first draft/drafts, functions were in/out, that was forsaken for the sake of purity from side-effects, then for the sake of the said side-effects access parameters are added (don't know if dispatching on access parameters/results were added at the same moment), yet they waited one more version to put back in-out function parameters... Surely there are many reasons (probably) but it still seems funny.
There was no clear understanding of the contracts back then. Absence of
side effects is a behavioral contract #1. It is different from absence
of effects on the parameters #2. One can have any combination of these
two. The choice was to have functions with any side effects allowed but
no effects on the parameters except the dedicated one = the result. It
was a pragmatic choice because that time it was impossible to have
contracts on the side effects. Now we have SPARK and profiles, it should
be possible.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
prev parent reply other threads:[~2018-06-12 8:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-11 21:49 why access parameter in stream attributes to begin with, instead of in or in/out ? Mehdi Saada
2018-06-11 22:48 ` Shark8
2018-06-11 23:17 ` Randy Brukardt
2018-06-12 6:28 ` Mehdi Saada
2018-06-12 8:30 ` Dmitry A. Kazakov [this message]
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