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Re: Patch: non-empty matches following empty ones
From: |
Stepan Kasal |
Subject: |
Re: Patch: non-empty matches following empty ones |
Date: |
Tue, 23 Aug 2005 16:24:05 +0200 |
User-agent: |
Mutt/1.4.1i |
Hi,
On Tue, Aug 23, 2005 at 07:09:20AM -0400, Charles Levert wrote:
> You've been MIA (missing in action) for a while
> on this list! :-)
> Good to read you back.
Sorry. I'll try to do better.
> Do you realize that for such patterns:
>
> -- every line matches;
>
> -- every place on a line where there isn't
> already a non-empty match, there will be
> an empty match between any two adjacent
> characters;
>
> -- with --only-matching, that will just
> produce a _lot_ of "filename:\n" lines;
>
> -- with --color, this will just produce a _lot_
> of human-invisible "\33[01;31m\33[K\33[m\33[K"
> pairs, along with possibly more such
> stuff around each non-matching character
> if GREP_COLORS is so configured (and the
> concern below addressed).
Sure, I understood that. That's what
sed 's/a*/X/g'
or
awk 'gsub(/a*/,"X")'
does.
Your arguments seem to show that grep should print only lines
with _nonempty_ matches. (Empty pattern might be an exception.)
But that's too late to change.
With current setup, the inconsistency will show up because
grep --colour 'a*'
will then print lot of lines without any colour tags.
It might be confusing for X-ray robots who expects to see the
tags...
I wanted to prefer consistency. Then I'd have to teach people that they
shouldn't use patterns which match empty string.
You wanted to change the specification of --only-matching (--colour),
so that it prints (colorifies) only non-empty matches.
OK, I no longer object to it. But please change the decumentation
(info and manpage) so that it states this clearly.
Have a nice day,
Stepan
- Patch: non-empty matches following empty ones, Charles Levert, 2005/08/22
- Re: Patch: non-empty matches following empty ones, Stepan Kasal, 2005/08/23
- Re: Patch: non-empty matches following empty ones, Charles Levert, 2005/08/23
- Re: Patch: non-empty matches following empty ones,
Stepan Kasal <=
- Re: Patch: non-empty matches following empty ones, Charles Levert, 2005/08/23
- Re: Patch: non-empty matches following empty ones, Charles Levert, 2005/08/23
- Re: Patch: non-empty matches following empty ones, Stepan Kasal, 2005/08/23
- Re: Patch: non-empty matches following empty ones, Julian Foad, 2005/08/26
- Re: Patch: non-empty matches following empty ones, Charles Levert, 2005/08/26