GNU bug report logs - #27681
grep: Combining Mark-Nonspacing are classified as [:punct:]

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Santiago <santiagorr <at> riseup.net>
To: bug-grep <at> gnu.org
Cc: 662629-submitter <at> bugs.debian.org
Subject: grep: Combining Mark-Nonspacing are classified as [:punct:]
Date: Thu, 13 Jul 2017 15:21:40 +0200

Hi,

I would like to forward the issue below, reported by Panu Kalliokoskii
in 2012 (better late than never!). I think the correct category is
Mark-nonspacing, but I am not very familiar with Unicode though.

It still occurs in grep 3.1. In this case, using the U+0301 acute accent:

 $ echo árbol | grep -o '[[:alpha:]]*'
 a
 rbol

Cheers,

 -- Santiago

On Mon, 05 Mar 2012 13:08:43 +0200 "Panu A. Kalliokoski" <atehwa <at> sange.fi> wrote:
> Package: grep
> Version: 2.6.3-3
> Severity: normal
> 
> 
> It seems that grep misclassifies combining letters (unicode class Lm) as
> punctuation, when they should be letters.  For instance:
> 
> $ echo d̪ʌ̀lì | grep -o '[[:alpha:]]*'
> d
> ʌ
> li
> 
> As a consequence, combining accents are not seen as "word-constituent":
> 
> $ echo d̪ʌ̀lì | grep -o '\w*'
> d
> ʌ
> li
> 
> This causes also false positives on word-boundary conditions, such as
> the below:
> 
> $ echo d̪ʌ̀lì | grep -w ʌ
> d̪ʌ̀lì
> 
> I suggest that combining letters should be part of [:alpha:] instead of
> [:punct:].

Message #8 received at 27681 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Santiago <santiagorr <at> riseup.net>, 27681 <at> debbugs.gnu.org
Cc: 662629-submitter <at> bugs.debian.org
Subject: Re: bug#27681: grep: Combining Mark-Nonspacing are classified as
 [:punct:]
Date: Thu, 13 Jul 2017 12:03:02 -0700

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

Surely this is a glibc bug, not a grep bug. Grep is just following the 
character classification of glibc. I can reproduce the problem by 
compiling and running the attached program, which uses only glibc (not 
grep). This program exits with status 1, whereas you want it to exit 
with status 0. So I suggest filing a glibc bug report.

[combining.c (text/x-csrc, attachment)]

Message #11 received at 27681 <at> debbugs.gnu.org (full text, mbox):

From: Santiago <santiagorr <at> riseup.net>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 27681 <at> debbugs.gnu.org
Subject: Re: bug#27681: grep: Combining Mark-Nonspacing are classified as
 [:punct:]
Date: Mon, 17 Jul 2017 11:20:36 +0200

El 13/07/17 a las 12:03, Paul Eggert escribió:
> Surely this is a glibc bug, not a grep bug. Grep is just following the
> character classification of glibc. I can reproduce the problem by compiling
> and running the attached program, which uses only glibc (not grep). This
> program exits with status 1, whereas you want it to exit with status 0. So I
> suggest filing a glibc bug report.

Done. Thanks,

  -- Santiago

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