GNU bug report logs - #46859
28.0.50; [PATCH]: Add option to truncate long lines in xref.el

Previous Next

Full log

Message #59 received at 46859 <at> debbugs.gnu.org (full text, mbox):

From: Gregory Heytings <gregory <at> heytings.org>
To: Dmitry Gutov <dgutov <at> yandex.ru>
Cc: 46859 <at> debbugs.gnu.org
Subject: Re: bug#46859: 28.0.50; [PATCH]: Add option to truncate long lines
 in xref.el
Date: Wed, 03 Mar 2021 17:11:12 +0000

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

>>> How so?  AFAICS, it's the exact same kind of output, except that it 
>>> gets truncated.  And it's (obviously?) better to see the context of 
>>> the pattern you are searching for, instead of the first characters of 
>>> the lines on which the pattern is found, in which the pattern might 
>>> not be present.
>> 
>> Since Grep doesn't return the column number of the match, we get it 
>> from parsing the string again. And if the string is now modified to be 
>> truncated from both sides, the column number will become wrong.
>
> I did not understand that you need the column number of the match. 
> That could perhaps become a feature request for GNU grep: with -o and 
> -n, also print the column number of the first character.
>

I wrote too fast.  In fact you can get the column number with GNU grep 
without parsing the original line:

grep -nb -oE '.{0,100}PATTERN.{0,100}'

Previous Next

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