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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Ada 2012 Constraints (WRT an Ada IR)
Date: Wed, 14 Dec 2016 13:52:40 +0100
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Date: 2016-12-14T13:52:40+01:00
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On 14/12/2016 13:44, G.B. wrote:
> On 14/12/2016 12:25, Dmitry A. Kazakov wrote:
>
>> That is the problem with implied contracts. Is this legal:
>>
>> begin
>>    loop
>>       X (Read (Stream));
>>    end loop;
>> exception
>>    when Constraint_Error =>
>>       null;
>> end;
>
>    "Assertions are not an input checking mechanism"
>    "To avoid a common misunderstanding, make sure to note
> that each of the contracts discussed holds between a routine
> (the supplier) and another routine (its caller): we are concerned
> about software-to-software communication, not software-to-human
> or software-to-outside-world. (...) Here there is no substitute
> for the usual condition-checking constructs, include the venerable
> IF ... THEN ...; the exception handling mechanism ... may also be
> helpful ". [1]
>
> [1] Meyer, Bertrand: OOSC2, 2nd ed, §11.6

Is it legal or not?

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