GNU bug report logs - #6743
Backslash regexp in Elisp manual

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Package: emacs;

Reported by: Arni Magnusson <arnima <at> hafro.is>

Date: Tue, 27 Jul 2010 23:33:01 UTC

Severity: normal

Done: Juanma Barranquero <lekktu <at> gmail.com>

Bug is archived. No further changes may be made.

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Message #8 received at 6743 <at> debbugs.gnu.org (full text, mbox):

From: Juanma Barranquero <lekktu <at> gmail.com>
To: Arni Magnusson <arnima <at> hafro.is>
Cc: 6743 <at> debbugs.gnu.org
Subject: Re: bug#6743: Backslash regexp in Elisp manual
Date: Wed, 28 Jul 2010 02:25:35 +0200

On Wed, Jul 28, 2010 at 01:31, Arni Magnusson <arnima <at> hafro.is> wrote:

>  Therefore, the read syntax for a regular expression matching
>  @samp{\} is @code{"\\\\"}.
>
> should be
>
>  Therefore, the read syntax for a regular expression matching
>  @samp{\\} is @code{"\\\\"}.

Why do you think so?

The section is talking about the read syntax. To match \, you need a
regexp with \\, and to write \\ in a string, you need \\\\.

Try

  emacs -Q
  \ <left>
  M-: (looking-at "\\") <RET>   => (invalid-regexp "Trailing backslash")
  q
  M-: (looking-at "\\\\") <RET> => t

Note that \\\\ is matching a single \ on the buffer, not \\

    Juanma
This bug report was last modified 14 years and 301 days ago.

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