From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,195f9d06474696b0
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news3.google.com!news.glorb.com!news.banetele.no!news.szn.dk!news.jacob-sparre.dk!pnx.dk!not-for-mail
From: Jacob Sparre Andersen <sparre@nbi.dk>
Newsgroups: comp.lang.ada
Subject: Re: Choice of variant record discriminant (design question)
Date: Mon, 31 Oct 2005 16:53:48 +0100
Organization: Jacob's private Usenet server
Message-ID: <m2pspl8yyb.fsf@hugin.crs4.it>
References: <m2acgwmpsu.fsf@hugin.crs4.it>
	<fP2dnZ4nFtAFQMLenZ2dnUVZ_smdnZ2d@megapath.net>
NNTP-Posting-Host: dhcp236.dhcp.nbi.dk
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: jacob-sparre.dk 1130774028 6748 172.24.5.236 (31 Oct 2005 15:53:48
 GMT)
X-Complaints-To: sparre@jacob-sparre.dk
NNTP-Posting-Date: Mon, 31 Oct 2005 15:53:48 +0000 (UTC)
User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux)
Cancel-Lock: sha1:7pNYvowBWQ+cGgTLqnXhFSO20qE=
Xref: g2news1.google.com comp.lang.ada:6075
Date: 2005-10-31T16:53:48+01:00
List-Id: <comp.lang.ada>

Randy Brukardt wrote:

> I have to wonder if the variant is worth it. There is not going to
> be any space savings,

Right.  But I hardly ever use variant records to save space.

> and in typical use, there isn't going to be much increase in safety,
> either.

Not that much, no.  But I prefer to let the code match the logic of
the problem.

> So I'd probably give up on the variant in this case, because I'd
> rather keep the aggregates (they are big help when a component needs
> to be added). But only you can weight that trade-off, because the
> relative value of the two options is something that depends on the
> components and the intended uses. (If the "empty" variant wasn't
> going to be empty in future version, for instance, the variant would
> make more sense.)

In this case, the null variant is most unlikely to end up containing
data later, so I can not use the argument that I may save space later
using this design.

If I didn't use that Ada allows me to encode the logic of my problem
in the source, couldn't I just as well use C or Fortran?

Thanks for the advice,

Jacob
-- 
"Only Hogwarts students really need spellcheckers"
                                -- An anonymous RISKS reader