From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Variant record question
Date: 2000/01/21
Date: 2000-01-21T00:00:00+00:00 [thread overview]
Message-ID: <wccr9fbchbg.fsf@world.std.com> (raw)
In-Reply-To: 4V0i4.622$dw3.29725@news.wenet.net
"Mike Silva" <mjsilva@jps.net> writes:
>...Why must
> I put in a default discriminant when I can then override it in an aggregate
> (variable 'A' below)?
It was a design goal of Ada 83 that it should be impossible to have an
uninitialized discriminant. Therefore, if you don't want to give a
value when you create each object, you have to have a default.
Also, having a default means that there can exist objects of the type
whose discriminant can change (unless the record is limited). That's
weird, IMHO -- there should have been a separate syntax for that. This
rule always seems to confuse people.
It was also a dresign goal that array components should always have the
same size.
- Bob
next prev parent reply other threads:[~2000-01-21 0:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-01-21 0:00 Variant record question Mike Silva
2000-01-21 0:00 ` Robert A Duff [this message]
2000-01-21 0:00 ` Ted Dennison
2000-01-21 0:00 ` Matthew Heaney
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