GNU bug report logs - #15107
24.3; replace-regexp-in-string wrong on \`

Previous Next

Full log

Message #30 received at 15107 <at> debbugs.gnu.org (full text, mbox):

From: Erik Anderson <erikbpanderson <at> gmail.com>
To: Noam Postavsky <npostavs <at> users.sourceforge.net>,
 Eli Zaretskii <eliz <at> gnu.org>
Cc: 15107 <at> debbugs.gnu.org
Subject: Re: bug#15107: [PATCH] Add replace-regexp-in-string regression test
Date: Wed, 31 Aug 2016 15:32:58 +0000

[Message part 1 (text/plain, inline)]

I suspect that since ".*" is such a commonly used term in regexps, Eli
might be misreading the regexp.

From the Emacs manual on regular expression special characters:
"‘.’ (Period)

is a special character that matches any single character except a newline.
Using concatenation, we can make regular expressions like ‘a.b’, which
matches any three-character string that begins with ‘a’ and ends with ‘b’."
You can verify the behavior of "."

(string-match "^." "No greedy modifiers here")
(match-data)
> (0 1)

(string-match "^.*" "This has a greedy modifier")
(match-data)
> (0 26)

This is a helpful document:
https://www.gnu.org/software/emacs/manual/html_node/elisp/Regexp-Special.html#Regexp-Special

Further discussion should be moved off this list.

-Erik.

On Wed, Aug 31, 2016 at 10:13 AM Noam Postavsky <
npostavs <at> users.sourceforge.net> wrote:

> On Wed, Aug 31, 2016 at 11:01 AM, Eli Zaretskii <eliz <at> gnu.org> wrote:
> >> From: Erik Anderson <erikbpanderson <at> gmail.com>
> >> Date: Wed, 31 Aug 2016 14:36:06 +0000
> >> Cc: 15107 <at> debbugs.gnu.org
> >>
> >> Per the replace-regexp-in-string docstring: "Replace all matches for
> REGEXP with REP in STRING."
> >
> > Yes, and there is a single match in this case, so a single
> > replacement.  The _entire_ input string matches the regexp, so after
> > that match there's nothing else left to match.
> >
> > What am I missing?
>
> "^." matches only the first character of "foo bar", but maybe you have
> a different idea of "matches" than I do. I would consider "^..*" to
> match the whole string.
>

[Message part 2 (text/html, inline)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.