From: Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>
Subject: Re: issue with implementing a visitor design pattern
Date: Tue, 27 Jan 2004 09:36:20 +0100
Date: 2004-01-27T09:36:20+01:00 [thread overview]
Message-ID: <c18c10pbb7edaj178snc54pfogna2ntt59@4ax.com> (raw)
In-Reply-To: wccllnubh0e.fsf@shell01.TheWorld.com
On 26 Jan 2004 15:18:41 -0500, Robert A Duff
<bobduff@shell01.TheWorld.com> wrote:
>Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> writes:
>
>> On 24 Jan 2004 16:44:02 -0500, Robert A Duff
>> <bobduff@shell01.TheWorld.com> wrote:
>>
>> >Dale Stanbrough <MrNoSpam@bigpoop.net.au> writes:
>> >
>> >> Robert A Duff wrote:
>>
>> >Adding "case on 'Tag" to Ada would not be trivial. One would have to
>> >reconcile the open-ended type extension capability of tagged types with
>> >the full-coverage rules of case statements.
>>
>> Same as with integer types, an obligatory:
>>
>> when others =>
>> ...
>
>"when others" *defeats* the full-coverage rules. It should be used only
>if you know it covers *all* the other cases, including the ones that
>haven't been invented yet!
It is a strange thing, "when others". Especially when others (:-)) is
empty, like in:
subtype Empty is String (0..-1);
X : Empty := (others => ' ');
--
Regards,
Dmitry A. Kazakov
www.dmitry-kazakov.de
next prev parent reply other threads:[~2004-01-27 8:36 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-15 19:22 issue with implementing a visitor design pattern cl1
2004-01-17 3:41 ` Robert I. Eachus
2004-01-17 21:24 ` Robert A Duff
2004-01-24 20:38 ` Dale Stanbrough
2004-01-24 21:44 ` Robert A Duff
2004-01-26 8:34 ` Dmitry A. Kazakov
2004-01-26 20:18 ` Robert A Duff
2004-01-27 8:36 ` Dmitry A. Kazakov [this message]
2004-02-01 0:32 ` Georg Bauhaus
2004-01-17 23:05 ` cl1
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