From: "Štěpán Němec" <stepnem@gmail.com>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: Andreas Schwab <schwab@linux-m68k.org>,
Tom <adatgyujto@gmail.com>,
emacs-devel@gnu.org
Subject: Re: Patch for lookaround assertion in regexp
Date: Mon, 23 Jan 2012 19:45:00 +0100 [thread overview]
Message-ID: <874nvm1cnn.fsf@gmail.com> (raw)
In-Reply-To: <jwvvco2fiu0.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Mon, 23 Jan 2012 12:11:26 -0500")
On Mon, 23 Jan 2012 18:11:26 +0100
Stefan Monnier wrote:
>>> If it doesn't then it's a job for the translation layer. Char syntaxes
>>> and categories could be converted into the standard [...] format.
>> Enumerating the syntax/category members is not an option.
>
> Indeed.
>
>> There is no easy way to do that.
>
> For `categories', there is a way, but the result is a *very* large [...]
> chunk, so it's impractical. For `syntax' there is indeed no way, since
> the syntax of a char doesn't only depend on the char itself but also of
> the `char-table' text-property that might be applied to that particular
> character position (and of course, if we ignore this problem, we're
> still back to the same problem of enormous [...] expressions, as is the
> case for categories).
> These entities really need to be implemented inside the regexp-engine
> (but they're usually pretty easy to implement there).
OTOH using something like PCRE would finally fix the currently erroneous
implementation of classes like [:space:], which now is the same as \s-.
(And personally I would gladly forgo the syntax categories for standard
[:classes:], although I imagine the former might be used by the
font-locking or somewhere... I never felt the need for them.)
--
Štěpán
next prev parent reply other threads:[~2012-01-23 18:45 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-23 11:17 Patch for lookaround assertion in regexp Colin Fraizer
2012-01-23 14:11 ` Stefan Monnier
2012-01-23 14:44 ` Tom
2012-01-23 14:50 ` Andreas Schwab
2012-01-23 15:19 ` Tom
2012-01-23 16:14 ` Andreas Schwab
2012-01-23 17:11 ` Stefan Monnier
2012-01-23 18:45 ` Štěpán Němec [this message]
2012-01-30 0:31 ` Juri Linkov
2012-01-23 15:31 ` Stefan Monnier
2012-01-24 8:41 ` Nikolai Weibull
2012-01-24 14:40 ` Stefan Monnier
2012-01-24 15:09 ` Nikolai Weibull
2012-01-24 17:34 ` Stefan Monnier
2012-01-24 23:27 ` David De La Harpe Golden
2012-01-25 6:07 ` Nikolai Weibull
2012-02-14 17:53 ` Daniel Colascione
2012-02-14 18:36 ` Stefan Monnier
2012-02-20 16:19 ` Dimitri Fontaine
2012-09-26 6:55 ` Tomohiro Matsuyama
-- strict thread matches above, loose matches on Subject: below --
2009-06-03 23:04 Tomohiro MATSUYAMA
2009-06-04 4:47 ` Miles Bader
2009-06-04 8:27 ` Deniz Dogan
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