From: Dave Abrahams <dave@boostpro.com>
To: rms@gnu.org
Cc: emacs-devel@gnu.org
Subject: Re: Should undefined behavior be encouraged in Emacs?
Date: Mon, 03 Oct 2011 22:18:48 -0400 [thread overview]
Message-ID: <m27h4lwlbr.fsf@pluto.luannocracy.com> (raw)
In-Reply-To: <E1RAuDy-00063B-VS@fencepost.gnu.org> (Richard Stallman's message of "Mon, 03 Oct 2011 21:55:14 -0400")
on Mon Oct 03 2011, Richard Stallman <rms-AT-gnu.org> wrote:
> > In simple cases such as (goto-char -5), users tend to see what the
> > behavior is, and are likely to write code that depends on it, even if
> > it isn't documented. Thus, leaving it undocumented doesn't mean that
> > we can change it and nobody will notice.
>
> If you make it a hard, inescapable error, that won't happen.
>
> That is true; this would pressure everyone to carefully make sure not
> to supply out-of-range arguments. But is that goal really more
> desirable than the convenience of rounding out-of-range arguments?
I would say it depends on the argument and its meaning. I remember when
I was working on a MIDI sequencer whose routines would assert that all
times used were nonnegative. For my code, that was a major PITA. I
would say the same probably applies to character positions.
Other arguments can't be so easily rounded (an int passed where a string
is expected), and probably some that can just shouldn't be
(e.g. indexing a vector).
--
Dave Abrahams
BoostPro Computing
http://www.boostpro.com
next prev parent reply other threads:[~2011-10-04 2:18 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-03 1:39 Should undefined behavior be encouraged in Emacs? Paul Eggert
2011-10-03 3:11 ` Stefan Monnier
2011-10-03 6:39 ` Andreas Röhler
2011-10-03 7:29 ` Stephen J. Turnbull
2011-10-03 8:58 ` Andreas Röhler
2011-10-06 2:17 ` Stephen J. Turnbull
2011-10-06 17:30 ` Richard Stallman
2011-10-06 19:49 ` Stephen J. Turnbull
2011-10-06 20:08 ` Andreas Röhler
2011-10-06 20:12 ` Lars Magne Ingebrigtsen
2011-10-06 20:46 ` Eli Zaretskii
2011-10-07 5:23 ` Andreas Röhler
2011-10-07 7:44 ` Stephen J. Turnbull
2011-10-07 7:52 ` John Wiegley
2011-10-07 17:27 ` Stephen J. Turnbull
2011-10-07 8:38 ` Alan Mackenzie
2011-10-07 15:26 ` Barry Warsaw
2011-10-07 18:06 ` ken manheimer
2011-10-07 18:21 ` Barry Warsaw
2011-10-07 18:46 ` Óscar Fuentes
2011-10-07 19:59 ` ken manheimer
2011-10-07 18:41 ` Drew Adams
2011-10-08 13:49 ` Miles Bader
2011-10-08 14:34 ` Drew Adams
2011-10-03 13:16 ` Stefan Monnier
2011-10-03 9:20 ` Alan Mackenzie
2011-10-03 9:52 ` Eli Zaretskii
2011-10-03 8:29 ` Andreas Schwab
2011-10-03 9:53 ` Eli Zaretskii
2011-10-03 13:13 ` Richard Stallman
2011-10-03 15:15 ` Dave Abrahams
2011-10-04 1:55 ` Richard Stallman
2011-10-04 2:18 ` Dave Abrahams [this message]
2011-10-03 16:14 ` Eli Zaretskii
2011-10-03 16:27 ` Andreas Schwab
2011-10-03 16:41 ` Eli Zaretskii
2011-10-04 1:55 ` Richard Stallman
2011-10-03 20:53 ` Paul Eggert
2011-10-03 14:49 ` Dave Abrahams
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=m27h4lwlbr.fsf@pluto.luannocracy.com \
--to=dave@boostpro.com \
--cc=emacs-devel@gnu.org \
--cc=rms@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).