From: Ken Garlington <garlingtonke@lmtas.lmco.com>
Subject: Re: Rules for Representation of Subtypes
Date: 1996/10/01
Date: 1996-10-01T00:00:00+00:00 [thread overview]
Message-ID: <32515744.3B83@lmtas.lmco.com> (raw)
In-Reply-To: qw6buemy9ea.fsf@gargantua.enst.fr
Samuel Tardieu wrote:
>
> >>>>> "Larry" == Larry Kilgallen <kilgallen@eisner.decus.org> writes:
>
> Larry> So can someone give an example of how Z'Valid _might_ be useful
> Larry> after an unchecked conversion, as seems to be indicated by the
> Larry> Reference Manual.
>
> I don't think that the Valid attribute has been put in the language to
> be used after an Unchecked_Conversion, but rather to be used after
> calls to imported subprograms and calls to Read attributes (data
> coming from a stream).
I don't know much, but I do know this: I specifically wrote a revision
request to Ada 83 to handle the following situation:
type Foo is range 1 .. 10;
X: Foo; -- assume that this takes up a storage unit with a range
-- greater than 1 .. 10
...
Read(X); -- some I/O operation, unchecked conversion, whatever
-- that might put a bit pattern in X that is not in 1 .. 10
if X in Foo then
raise Some_Exception; -- rarely works in Ada 83 due to optimization
end if;
I thought one of the important uses of X'Valid was to be able to test
for a legal bit pattern, and never mind the optimizations. If it doesn't
work, then why did I go to all the trouble to write the RR?
--
LMTAS - "Our Brand Means Quality"
next prev parent reply other threads:[~1996-10-01 0:00 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-09-22 0:00 Rules for Representation of Subtypes Matthew Heaney
1996-09-23 0:00 ` David C. Hoos, Sr.
1996-09-23 0:00 ` Robert A Duff
1996-09-23 0:00 ` Samuel T. Harris
1996-09-26 0:00 ` David C. Hoos, Sr.
1996-09-24 0:00 ` Robert Dewar
1996-09-26 0:00 ` Keith Thompson
1996-09-26 0:00 ` Matthew Heaney
1996-09-27 0:00 ` Robert Dewar
1996-09-27 0:00 ` Robert A Duff
1996-09-27 0:00 ` Robert Dewar
1996-09-27 0:00 ` Robert A Duff
1996-09-24 0:00 ` Robert Dewar
1996-09-23 0:00 ` Robert A Duff
1996-09-24 0:00 ` Matthew Heaney
1996-09-26 0:00 ` Robert A Duff
1996-09-26 0:00 ` Larry Kilgallen
1996-09-27 0:00 ` Robert A Duff
1996-09-27 0:00 ` Mark A Biggar
1996-09-30 0:00 ` Robert A Duff
1996-10-01 0:00 ` Larry Kilgallen
1996-10-01 0:00 ` Robert A Duff
1996-10-01 0:00 ` Samuel Tardieu
1996-10-01 0:00 ` Ken Garlington [this message]
1996-10-01 0:00 ` Valid Attribute and Unchecked Conversion Matthew Heaney
1996-10-02 0:00 ` Robert A Duff
1996-10-04 0:00 ` Keith Thompson
1996-10-04 0:00 ` Matthew Heaney
1996-10-07 0:00 ` Robert Dewar
1996-10-09 0:00 ` Keith Thompson
1996-10-04 0:00 ` Robert A Duff
1996-10-04 0:00 ` Robert Dewar
1996-10-11 0:00 ` Norman H. Cohen
1996-10-12 0:00 ` Robert Dewar
1996-10-06 0:00 ` Keith Thompson
1996-10-07 0:00 ` Robert Dewar
1996-10-09 0:00 ` Keith Thompson
1996-10-07 0:00 ` Ken Garlington
1996-10-08 0:00 ` Alan Brain
1996-10-07 0:00 ` Kenneth Almquist
1996-10-07 0:00 ` Robert Dewar
1996-10-10 0:00 ` Ken Garlington
1996-10-11 0:00 ` Robert Dewar
1996-10-14 0:00 ` Keith Thompson
1996-10-14 0:00 ` Ken Garlington
1996-09-28 0:00 ` Rules for Representation of Subtypes Larry Kilgallen
1996-09-29 0:00 ` Robert A Duff
1996-09-29 0:00 ` Larry Kilgallen
1996-09-29 0:00 ` Matthew Heaney
1996-09-30 0:00 ` Robert A Duff
1996-10-01 0:00 ` Ken Garlington
1996-10-02 0:00 ` Robert A Duff
1996-10-02 0:00 ` Ken Garlington
1996-10-06 0:00 ` Robert Dewar
1996-09-29 0:00 ` Matthew Heaney
1996-09-30 0:00 ` Robert Dewar
1996-09-30 0:00 ` Matthew Heaney
1996-09-30 0:00 ` Robert A Duff
1996-10-03 0:00 ` Robert Dewar
1996-10-02 0:00 ` Valid Attribute and Unchecked Conversion George Haddad
1996-10-03 0:00 ` John Herro
1996-10-04 0:00 ` Karl Cooper {46901}
1996-10-07 0:00 ` Mark A Biggar
1996-10-08 0:00 ` Robert Dewar
1996-10-05 0:00 ` Robert Dewar
1996-10-06 0:00 ` Keith Thompson
1996-10-14 0:00 ` Robert A Duff
1996-10-02 0:00 ` Robert I. Eachus
1996-10-02 0:00 ` Matthew Heaney
1996-09-27 0:00 ` Rules for Representation of Subtypes Matthew Heaney
1996-09-27 0:00 ` Robert A Duff
-- strict thread matches above, loose matches on Subject: below --
1996-09-28 0:00 Robert Dewar
1996-09-29 0:00 ` Robert A Duff
1996-09-29 0:00 ` Matthew Heaney
1996-09-28 0:00 Robert Dewar
1996-09-29 0:00 ` Robert A Duff
1996-09-29 0:00 ` Robert Dewar
1996-09-30 0:00 ` Art Schwarz
1996-09-30 0:00 ` Robert A Duff
1996-10-01 0:00 ` Larry Kilgallen
1996-10-01 0:00 ` Robert A Duff
1996-10-01 0:00 ` Brian R. Hanson
1996-09-29 0:00 ` Matthew Heaney
1996-09-28 0:00 Robert Dewar
1996-09-30 0:00 ` Keith Thompson
1996-10-02 0:00 Franco Mazzanti
1996-10-03 0:00 ` Robert A Duff
1996-10-03 0:00 Franco Mazzanti
1996-10-03 0:00 ` Robert A Duff
1996-10-10 0:00 W. Wesley Groleau (Wes)
1996-10-10 0:00 ` Robert Dewar
1996-10-11 0:00 ` Ken Garlington
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