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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: What about a Static_Assertion?
Date: Tue, 23 Jul 2013 22:13:15 +0200
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Date: 2013-07-23T22:13:15+02:00
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On Tue, 23 Jul 2013 20:57:05 +0200, Yannick Duchêne (Hibou57) wrote:

> Le Tue, 23 Jul 2013 20:43:19 +0200, Dmitry A. Kazakov  
> <mailbox@dmitry-kazakov.de> a écrit:
> 
>> On Tue, 23 Jul 2013 20:07:54 +0200, Yannick Duchêne (Hibou57) wrote:
>>
>>> Don't you believe it would be great to have static assertion just like  
>>> we have static predicates?
>>
>> What is the difference between assertion and precondition or invariant?
> 
> An assertion may applies to multiple things at a time. I like to see an  
> assertion as hypothesis (and I prefer the hypothesis to be statically  
> checkable :-P ), and it is an hypothesis I may refer to from multiple  
> place in a package (although I may like to duplicate it in multiple case),  
> not from a single sub‑program.

This does not make any sense. Provided we are talking about static things,
they by definition hold to the program as a whole.
 
> By the way, I don't believe assertions are seen as a deprecated feature,  
> and that suggest from many one's eyes, it is indeed different and can't be  
> replaced by the actual predicates.

Predicate by definition is a Boolean expression.

http://en.wikipedia.org/wiki/Predicate_%28mathematical_logic%29

Assertion, precondition, postcondition, invariant are all predicates. What
Ada 2012 calls "static predicate" is also a predicate.

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