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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: about the new Ada 2012 pre/post conditions
Date: Thu, 5 Jul 2012 09:24:57 +0200
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Date: 2012-07-05T09:24:57+02:00
List-Id: <comp.lang.ada>

On Wed, 4 Jul 2012 19:58:31 -0700 (PDT), Shark8 wrote:

> Also, I don't know where you got the idea that pre- and post-conditions
> must not implement anything.

Trivial:

IF pre-/post-condition is contract THEN they are not implementation

[POV #2]

(Historically, pre-/post-conditions were invented by Dijkstra for the
purpose of proving correctness. Later they were used for types to analyze
substitutability issues etc.)

ELSE ... [POV #1]

> If that was the case then, strictly speaking
> JavaDoc's pre and postcondition annotating comments are superior to Ada's
> pre and post condition because they don't implement anything and are, in
> fact, just comments having no actual impact on the program text.

Not if condition proof fault makes the program illegal.

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