* Re: non-greedy matching?
[not found] <20010321142303.B8924@thelonious.new.ox.ac.uk>
@ 2001-03-21 15:52 ` Peter Stephenson
2001-03-21 16:02 ` Peter Stephenson
2001-03-21 23:00 ` Adam Spiers
1 sibling, 1 reply; 5+ messages in thread
From: Peter Stephenson @ 2001-03-21 15:52 UTC (permalink / raw)
To: Zsh hackers list
Adam Spiers <adam@spiers.net> wrote:
> They are done in order to strip control characters from a prompt so
> that its display width can be determined. At first I thought that it
> would surely be easy to avoid this, but I still haven't come up with a
> quick replacement, since neither zsh nor sed seem to be able to do
> non-greedy matching.
You can, it's in the manual.
% foo='%{one%}hello%{two%}'
% print ${(S)foo//[%]\{*[%]\}}
hello
Don't ask me why you need to put the `%' in square brackets --- there may
be some stray (s)printf in the code, for example. (Do tell me if you know
what it is.)
--
Peter Stephenson <pws@csr.com> Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK Tel: +44 (0)1223 392070
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: non-greedy matching?
2001-03-21 15:52 ` non-greedy matching? Peter Stephenson
@ 2001-03-21 16:02 ` Peter Stephenson
0 siblings, 0 replies; 5+ messages in thread
From: Peter Stephenson @ 2001-03-21 16:02 UTC (permalink / raw)
To: Zsh hackers list
> % foo='%{one%}hello%{two%}'
> % print ${(S)foo//[%]\{*[%]\}}
> hello
>
> Don't ask me why you need to put the `%' in square brackets --- there may
> be some stray (s)printf in the code, for example. (Do tell me if you know
> what it is.)
I just realised: //% means match only at the end.
% print ${(S)foo//\\%\{*[%]\}}
also works. I always loathed that syntax: it's unmemorable and hacky (all
right, it's not on its own).
--
Peter Stephenson <pws@csr.com> Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK Tel: +44 (0)1223 392070
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: non-greedy matching?
[not found] <20010321142303.B8924@thelonious.new.ox.ac.uk>
2001-03-21 15:52 ` non-greedy matching? Peter Stephenson
@ 2001-03-21 23:00 ` Adam Spiers
2001-03-22 0:09 ` Bart Schaefer
1 sibling, 1 reply; 5+ messages in thread
From: Adam Spiers @ 2001-03-21 23:00 UTC (permalink / raw)
To: Zsh hackers list
Peter Stephenson (pws@csr.com) wrote:
> Adam Spiers <adam@spiers.net> wrote:
> > They are done in order to strip control characters from a prompt so
> > that its display width can be determined. At first I thought that it
> > would surely be easy to avoid this, but I still haven't come up with a
> > quick replacement, since neither zsh nor sed seem to be able to do
> > non-greedy matching.
>
> You can, it's in the manual.
>
> % foo='%{one%}hello%{two%}'
> % print ${(S)foo//[%]\{*[%]\}}
> hello
*gobsmacked*
I think that's the least uncomfortable I've ever felt after being
RTFM'd, given that you're apparently the only -worker who remembered
if that flag's existence ;-)
Can I suggest that it be made slightly more self-evident in the
manual, for instance via this patch? I would expect most people
searching for this feature in the manual to use the keyword `greedy'.
Index: Doc/Zsh/expn.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/expn.yo,v
retrieving revision 1.26
diff -u -r1.26 expn.yo
--- Doc/Zsh/expn.yo 2001/03/12 17:39:24 1.26
+++ Doc/Zsh/expn.yo 2001/03/21 22:59:30
@@ -779,8 +779,8 @@
Search substrings as well as beginnings or ends; with tt(#) start
from the beginning and with tt(%) start from the end of the string.
With substitution via tt(${)...tt(/)...tt(}) or
-tt(${)...tt(//)...tt(}), specifies that the shortest instead of the
-longest match should be replaced.
+tt(${)...tt(//)...tt(}), specifies non-greedy matching, i.e. that the
+shortest instead of the longest match should be replaced.
)
item(tt(I:)var(expr)tt(:))(
Search the var(expr)th match (where var(expr) evaluates to a number).
> I just realised: //% means match only at the end.
> % print ${(S)foo//\\%\{*[%]\}}
> also works.
Is there no limit to what zsh can do? :-)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: non-greedy matching?
2001-03-21 23:00 ` Adam Spiers
@ 2001-03-22 0:09 ` Bart Schaefer
2001-03-22 10:32 ` Peter Stephenson
0 siblings, 1 reply; 5+ messages in thread
From: Bart Schaefer @ 2001-03-22 0:09 UTC (permalink / raw)
To: Zsh hackers list
On Mar 21, 11:00pm, Adam Spiers wrote:
} Subject: Re: non-greedy matching?
}
} Can I suggest that it be made slightly more self-evident in the
} manual, for instance via this patch? I would expect most people
} searching for this feature in the manual to use the keyword `greedy'.
I don't think I would have thought of searching for "greedy" ... but
then I obviously never thought of searching for it at all.
And having this as a parameter expansion flag doesn't help when it
comes to glob patterns, which is (I rationalize) why I never thought
of searching for it.
Anyone for adding another extendedglob flag? (#g)? (Maybe another
letter would be better, since the flag would turn -off- greediness.)
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.brasslantern.com
Zsh: http://www.zsh.org | PHPerl Project: http://phperl.sourceforge.net
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: non-greedy matching?
2001-03-22 0:09 ` Bart Schaefer
@ 2001-03-22 10:32 ` Peter Stephenson
0 siblings, 0 replies; 5+ messages in thread
From: Peter Stephenson @ 2001-03-22 10:32 UTC (permalink / raw)
To: Zsh hackers list
Bart wrote:
> And having this as a parameter expansion flag doesn't help when it
> comes to glob patterns, which is (I rationalize) why I never thought
> of searching for it.
>
> Anyone for adding another extendedglob flag? (#g)? (Maybe another
> letter would be better, since the flag would turn -off- greediness.)
It's not currently done in the globbing code, it's done by looping in the
parameter code. It could be tricky to add directly.
--
Peter Stephenson <pws@csr.com> Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK Tel: +44 (0)1223 392070
^ permalink raw reply [flat|nested] 5+ messages in thread
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[not found] <20010321142303.B8924@thelonious.new.ox.ac.uk>
2001-03-21 15:52 ` non-greedy matching? Peter Stephenson
2001-03-21 16:02 ` Peter Stephenson
2001-03-21 23:00 ` Adam Spiers
2001-03-22 0:09 ` Bart Schaefer
2001-03-22 10:32 ` Peter Stephenson
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