unofficial mirror of bug-guile@gnu.org 
 help / color / mirror / Atom feed
From: Mark H Weaver <mhw@netris.org>
To: Andy Wingo <wingo@pobox.com>
Cc: David Kastrup <dak@gnu.org>, 17049@debbugs.gnu.org
Subject: bug#17049: [PATCH] Make reverse! forego the cost of SCM_VALIDATE_LIST
Date: Fri, 21 Mar 2014 00:38:46 -0400	[thread overview]
Message-ID: <87pplgnp2h.fsf@yeeloong.lan> (raw)
In-Reply-To: <87bnx0y4qk.fsf@pobox.com> (Andy Wingo's message of "Thu, 20 Mar 2014 21:50:11 +0100")

Andy Wingo <wingo@pobox.com> writes:

> On Thu 20 Mar 2014 12:23, David Kastrup <dak@gnu.org> writes:
>
>> +  /* We did not start with a proper list.  Undo the reversal. */
>
> I'm hesitant.  This is visible to other threads.  (Granted there has to
> be significant wrongness if we get here...)

If one thread attempts to access a list that's being destructively
reversed by another thread, the behavior is undefined.  Incidentally,
that's also the reason that your recent changes to 'for-each' are
defensible, Andy.  Therefore, I strongly believe this to be a non-issue.

I have yet to review this patch properly (except to notice that it does
not follow the GNU coding standards w.r.t. bracket placement, which
needs to be fixed), but based on the high-level description, it sounds
good to me, and also quite clever.

    Regards,
      Mark





  parent reply	other threads:[~2014-03-21  4:38 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-20 11:23 bug#17049: [PATCH] Make reverse! forego the cost of SCM_VALIDATE_LIST David Kastrup
2014-03-20 11:38 ` bug#17049: PostScriptum: David Kastrup
2014-03-20 14:19 ` bug#17049: [PATCH] Make reverse! forego the cost of SCM_VALIDATE_LIST David Kastrup
2014-03-20 20:50 ` Andy Wingo
2014-03-20 21:27   ` David Kastrup
2014-03-21  4:38   ` Mark H Weaver [this message]
2014-03-21 16:56     ` David Kastrup
2014-03-31 19:56       ` Mark H Weaver
2014-04-01 10:26         ` bug#17049: [PATCH v2] " David Kastrup
2014-04-01 10:40           ` David Kastrup
2014-04-01 14:09             ` Mark H Weaver
2014-04-01 14:24               ` bug#17049: [PATCH v3] " David Kastrup
2014-04-01 16:35                 ` Mark H Weaver
2014-03-21 17:44   ` bug#17049: [PATCH] " David Kastrup
2014-03-30 16:36 ` bug#17049: Further change ideas David Kastrup

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/guile/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87pplgnp2h.fsf@yeeloong.lan \
    --to=mhw@netris.org \
    --cc=17049@debbugs.gnu.org \
    --cc=dak@gnu.org \
    --cc=wingo@pobox.com \
    /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. 
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).