From: Adam Spiers <adam@spiers.net>
To: org-mode mailing list <emacs-orgmode@gnu.org>
Subject: Re: proposal: defconst/defcustom org-tags-regexp
Date: Fri, 20 Jul 2007 16:05:13 +0100 [thread overview]
Message-ID: <20070720150513.GB28297@atlantic.linksys.moosehall> (raw)
In-Reply-To: <56626b2502c1e0ead302243cb947b0b2@science.uva.nl>
On Wed, Jul 18, 2007 at 11:24:40PM +0200, Carsten Dominik wrote:
> On Jul 16, 2007, at 15:21, Adam Spiers wrote:
> >There seem to be a number of hardcoded regexps currently used for
> >matching heading tags, all very similar looking, and typically
> >something like:
> >
> > [ \t]*\\(:[[:alnum:]_@:]+:\\)?[ \t]*\\($\\|\r\\)
> >
> >Is there any reason why these shouldn't be factored out into a new
> >defcustom org-tags-regexp?
>
> Well, one reason is efficiency. When a regular expression is a
> constant,
> Emacs is able to cache the compiled version of the regular expression,
> and this can speed up code that does a lot of matching quite a bit. The
> token you show above is usually part of a larger string, so the full
> regular expression would have to be make with concat and will therefore
> be recompiled all the time.
Right, point taken - like m//o in Perl. To be honest, it doesn't
matter too much to me if it's defconst rather than defcustom. The
main thing is that I can have tags starting with '<' :-)
I suggest that we start by refactoring into a defconst, and then we
can worry about turning that into a defcustom in a way which retains
efficiency at a later date - if anyone needs the defcustom badly
enough. Makes sense?
Cheers,
Adam
next prev parent reply other threads:[~2007-07-20 15:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-16 13:21 proposal: defconst/defcustom org-tags-regexp Adam Spiers
2007-07-18 21:24 ` Carsten Dominik
2007-07-19 13:08 ` Eddward DeVilla
2007-07-19 15:08 ` Carsten Dominik
2007-07-19 16:14 ` Eddward DeVilla
2007-07-20 15:05 ` Adam Spiers [this message]
[not found] ` <931245f7aaa24436377e537552f1beab@science.uva.nl>
2007-09-01 11:01 ` Adam Spiers
2007-09-02 7:30 ` Carsten Dominik
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.orgmode.org/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20070720150513.GB28297@atlantic.linksys.moosehall \
--to=adam@spiers.net \
--cc=emacs-orgmode@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/org-mode.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).