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Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely w
From: |
Tim Landscheidt |
Subject: |
Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)? |
Date: |
Tue, 23 Feb 2010 12:33:02 +0000 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) |
John Withers <grayarea@reddagger.org> wrote:
> You are completely correct on all counts. What I should have said was
> that for many classes of problems I run into during my daily work the
> ability to write a regex is much faster than using a parser (and
> definitely than writing one). And that I find the classes of problems
> that fit that mold increased by having lookahead/behind assertions.
> I use parsers more frequently than I use regexes, but a lot of the one
> shot work I do on logs, semi-structured text files of various types and
> in very, very limited cases some html where the html is already
> processed in some way; a quick regex is much faster for me, and I
> imagine almost everyone, but I could be wrong.
> [...]
Same with me; and I would add that the maintainability in-
creases drastically as well. If I have to revisit a term
like:
| (while (re-search-forward "foo" nil t)
| (save-match-data
| (when (not (looking-at "bar"))
| (replace-match "XYZ")))))
or even:
| foo\($\|[^b]\|b[^a]\|ba[^r]\)
I need much more time to understand what I tried to achieve
than with:
| foo(?!bar)
Furthermore, if the handmade parser has a subtle deviation
from what you would expect it to look like, you spend even
more time figuring out whether that was a wanted effect or a
bug not yet discovered.
Tim
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, (continued)
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, Pascal J. Bourguignon, 2010/02/18
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, John Withers, 2010/02/18
- Message not available
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, Pascal J. Bourguignon, 2010/02/18
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, John Bokma, 2010/02/18
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, John Withers, 2010/02/18
- Message not available
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, David Combs, 2010/02/18
- Message not available
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, Pascal J. Bourguignon, 2010/02/18
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, John Withers, 2010/02/18
- Message not available
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, Tim X, 2010/02/19
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, John Withers, 2010/02/20
- Message not available
- Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?,
Tim Landscheidt <=
Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, Tyler Smith, 2010/02/18
Message not available
Re: Perl, etc has these "?"-prefix modifiers/codes/whatever. Precisely which does emacs have (and NOT have)?, Stefan Monnier, 2010/02/24