From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Subject: Re: Did I find a bug here?
Date: Sat, 3 Apr 2021 11:18:47 +0300 [thread overview]
Message-ID: <icqmn8F3h91U1@mid.individual.net> (raw)
In-Reply-To: <s492mr$d5e$1@dont-email.me>
On 2021-04-03 9:41, J-P. Rosen wrote:
> Le 03/04/2021 à 07:46, reinert a écrit :
>> Could AB_Type(X) in "case AB_Type(X) is" function as such a valid check?
> Yes,
I believe not. The use of X as an argument to a type conversion is an
"evaluation" of X, by RM 4.6(28), which can be a bounded error by RM
13.9.1(9) if X'Valid is False.
That bounded error can lead to an exception or simply to continued
execution with the invalid value.
> but I recommend "case AB_Type'(X) is", i.e. a qualification rather
> than a conversion.
That also requires an evaluation of X, by RM 4.7(4), and again can be a
bounded error if X'Valid is False.
The use of X in X'Valid is explicitly defined to mean that X is "read"
but is not "evaluated", RM 13.9.2(12)(13). So it seems to be the only
safe way to check for validity.
next prev parent reply other threads:[~2021-04-03 8:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 6:30 Did I find a bug here? reinert
2021-04-02 7:30 ` J-P. Rosen
2021-04-02 8:33 ` Niklas Holsti
2021-04-03 5:46 ` reinert
2021-04-03 6:41 ` J-P. Rosen
2021-04-03 8:18 ` Niklas Holsti [this message]
2021-04-03 12:37 ` J-P. Rosen
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2021-04-02 6:15 reinert
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