From: Ted Dennison <dennison@telepath.com>
Subject: Re: Three simple questions
Date: 2000/10/11
Date: 2000-10-11T00:00:00+00:00 [thread overview]
Message-ID: <39E4A0B5.6A6FEA0E@telepath.com> (raw)
In-Reply-To: 39E47660.3F85CAF9@averstar.com
Tucker Taft wrote:
> Ted Dennison wrote:
> >
> > In article <39E30759.7A402CB6@bton.ac.uk>,
> > John English <je@bton.ac.uk> wrote:
> > > I agree completely -- from a safety point of view, something like
> > > this is surely essential for Ada 0X...
> >
> > I'm glad I'm not the only one who feels that way.
>
> You'll be happy to know that pragmas have been proposed that
> allow the programmer to prevent this kind of mistake. See AI-218, at:
>
> http://www.ada-auth.org/cgi-bin-acats/cvsweb.cgi/AIs/AI-00218.DOC?rev=1.4
After looking over that AI, I think I'd rather see us wait for Ada0XX and fix
it "right". They are clearly a bit of a hack, but I'm worried that they will
become the permanent solution once they are officially blessed..
Since we already have a keyword to designate dispatching operations without
implementations (abstract), it wouldn't be a big conceptual leap to make
keywords to designate overriding dispatching operations ("overrides", or
perhaps "is new"). The big problem is that leaving the default behavior in a
backward-compatable state is undesirable. Perhaps the best solution would be
leave the default the way it is, and to also have an optional keyword
designating that the routine *cannot* be an override. Then it could probably
be left to coding standards to enforce usage of the appropriate keywords
(rather than taking the default). This would mesh with the situation we
currently have with the "in" parameter mode.
The text dismisses the keyword solution above as ugly (and new keywords as
"bad"). But the pragma solution is even uglier, as it comes on a completly
separate line. Worse yet, the pragma wouldn't appear in the body at all (which
is where I went looking for the source of my "bug").
In general I think the proposed pragmas are just a hack to cover what should
be a first-class part of the language. I do agree wholeheartedly with the part
of the AI that says "Syntax was determined to be too heavyweight a solution
for an amendment.". Of course that would make us wait until the next full
language revision, whereas pragmas can be applied now.
--
T.E.D.
Home - mailto:dennison@telepath.com Work - mailto:dennison@ssd.fsi.com
WWW - http://www.telepath.com/dennison/Ted/TED.html ICQ - 10545591
next prev parent reply other threads:[~2000-10-11 0:00 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-10-09 0:00 Three simple questions Frank Christiny
2000-10-09 0:00 ` John McCabe
2000-10-09 0:00 ` Frank Christiny
2000-10-10 0:00 ` John English
2000-10-10 0:00 ` Dale Stanbrough
2000-10-10 0:00 ` Larry Kilgallen
2000-10-10 0:00 ` John English
2000-10-10 0:00 ` Ted Dennison
2000-10-11 0:00 ` Tucker Taft
2000-10-11 0:00 ` Ted Dennison [this message]
2000-10-12 0:00 ` Tucker Taft
2000-10-12 0:00 ` The AI process (was: Three simple questions) Ted Dennison
2000-10-12 0:00 ` Marc A. Criley
2000-10-12 0:00 ` Tucker Taft
2000-10-16 0:00 ` Three simple questions Robert A Duff
2000-10-11 0:11 ` wv12
2000-10-10 0:00 ` Larry Kilgallen
2000-10-14 3:25 ` Robert Dewar
2000-10-15 0:00 ` The Ludwig Family
2000-10-16 0:00 ` Florian Weimer
2000-10-17 0:00 ` David Starner
2000-10-18 0:00 ` Florian Weimer
2000-10-19 0:00 ` David Starner
2000-10-21 0:00 ` Robert Dewar
2000-10-21 0:00 ` David Starner
2000-10-23 0:00 ` Robert A Duff
2000-10-28 11:00 ` Robert Dewar
2000-10-28 10:56 ` Robert Dewar
2000-10-28 10:57 ` Robert Dewar
2000-10-21 0:00 ` Robert Dewar
2000-10-21 0:00 ` David Starner
2000-10-16 3:10 ` Robert Dewar
2000-10-17 0:00 ` The Ludwig Family
2000-10-16 0:00 ` Robert A Duff
2000-10-16 0:00 ` James Hassett
2000-10-16 0:00 ` Robert Dewar
2000-10-16 0:00 ` Robert Dewar
2000-10-11 0:00 ` John English
2000-10-11 0:00 ` Pascal Obry
2000-10-11 0:00 ` mjsilva
2000-10-11 0:00 ` David Gillon
2000-10-11 2:12 ` DuckE
2000-10-10 0:00 ` Larry Kilgallen
2000-10-10 0:00 ` Case for case-sensitivity (Was: Three simple questions) Frank Christiny
2000-10-10 0:00 ` David C. Hoos, Sr.
2000-10-10 0:00 ` tmoran
2000-10-10 0:00 ` mjsilva
2000-10-10 0:00 ` John Magness
2000-10-10 0:00 ` Ted Dennison
2000-10-10 0:00 ` David Starner
2000-10-12 0:00 ` John English
2000-10-11 0:00 ` dmitry6243
2000-10-11 0:00 ` John English
2000-10-11 0:00 ` Frank Christiny
2000-10-12 0:00 ` Larry Kilgallen
2000-10-14 0:00 ` nickerson
2000-10-15 1:48 ` Robert Dewar
2000-10-15 0:00 ` Jean-Pierre Rosen
2000-10-11 4:39 ` Ken Garlington
2000-10-10 0:47 ` Three simple questions Larry Elmore
2000-10-10 1:16 ` Ed Falis
2000-10-11 3:47 ` Jeff Carter
2000-10-13 0:00 ` Philippe Torres
2000-10-13 0:00 ` Stefan Skoglund
2000-10-10 0:00 ` Pascal Obry
2000-10-11 3:59 ` Jeff Carter
2000-10-14 0:00 ` Keith Thompson
2000-10-10 0:42 ` Ken Garlington
2000-10-11 0:00 ` Pat Rogers
2000-10-11 0:00 ` Marin David Condic
2000-10-13 0:00 ` Keith Thompson
2000-10-13 0:00 ` Marin David Condic
2000-10-13 0:00 ` Wes Groleau
[not found] ` <39EAEEEA.4F58C47C@cepsz.unizar.es>
2000-10-16 0:00 ` David Starner
2000-10-16 0:00 ` Robert A Duff
2000-10-16 0:00 ` Larry Kilgallen
2000-10-16 0:00 ` Florian Weimer
2000-10-17 0:43 ` Robert Dewar
2000-10-17 0:00 ` Larry Kilgallen
2000-10-17 0:00 ` Florian Weimer
2000-11-03 7:24 ` E. E. Cummings (was Re: Three simple questions) Robert I. Eachus
2000-10-17 0:00 ` Three simple questions Keith Thompson
2000-10-17 0:00 ` Wes Groleau
2000-10-14 0:37 ` Ken Garlington
2000-10-14 0:00 ` Richard Kenner
2000-10-14 0:00 ` Laurent Guerby
2000-10-16 0:00 ` Robert A Duff
2000-10-16 0:00 ` Laurent Guerby
2000-10-17 0:00 ` Ronald Cole
2000-10-17 0:00 ` Wes Groleau
2000-10-14 0:00 ` Marin David Condic
2000-10-11 0:00 ` Larry Hazel
2000-10-11 0:00 ` Tucker Taft
2000-10-12 1:05 ` Bjarne Bäckström
2000-10-13 0:00 ` Anders Wirzenius
2000-10-13 0:00 ` Wes Groleau
2000-10-14 3:28 ` Robert Dewar
2000-10-13 0:00 ` Bjarne Bäckström
2000-10-16 0:00 ` Anders Wirzenius
2000-10-11 0:00 ` Simon Wright
2000-10-14 0:00 ` Robert Dewar
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