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From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Variant record question
Date: 2000/01/21
Message-ID: <wccr9fbchbg.fsf@world.std.com>#1/1
X-Deja-AN: 575860896
Sender: bobduff@world.std.com (Robert A Duff)
References: <4V0i4.622$dw3.29725@news.wenet.net>
Organization: The World Public Access UNIX, Brookline, MA
Newsgroups: comp.lang.ada
Date: 2000-01-21T00:00:00+00:00
List-Id: <comp.lang.ada>

"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