From: Bart Schaefer <schaefer@brasslantern.com>
To: zsh-users@zsh.org
Subject: Re: backreferences
Date: Thu, 15 Oct 2015 19:30:32 -0700 [thread overview]
Message-ID: <151015193032.ZM30783@torch.brasslantern.com> (raw)
In-Reply-To: <56204FD3.9040500@eastlink.ca>
On Oct 15, 6:16pm, Ray Andrews wrote:
} Subject: Re: backreferences
}
} if [[ "$sstring" = (#b)([(^(edcba))]*)(edcba)(*) ]];
Umm, no. [(^(edcba))] is still a character class (open paren, caret,
e,d,c,b,a, close paren). Just (^(edcba)) without the square brackets.
And you have more parens then, so your $match[] indexes are wrong.
if [[ "$sstring" = (#b)((^(edcba))*)(edcba)(*) ]]
There are 5 sets of parens, and you care about $match[1], $match[4],
and $match[5]. $match[2] is the prefix of $match[1] that was not
consumed by the middle *, and $match[3] is an empty substring of
$match[2] (because it was excluded from matching). Count off the
open parens left to right to see this.
In fact you don't even need the middle * because (^edcba) will eat
an arbitrarily long string as long as it is not literally "edcba".
So you can reduce this to
if [[ "$sstring" = (#b)(^edcba)(edcba)(*) ]]
and then you're back to only needing $match[1,3].
next prev parent reply other threads:[~2015-10-16 2:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-15 18:28 backreferences Ray Andrews
2015-10-15 23:16 ` backreferences Bart Schaefer
2015-10-16 1:16 ` backreferences Ray Andrews
2015-10-16 2:30 ` Bart Schaefer [this message]
2015-10-16 4:11 ` backreferences Mikael Magnusson
2015-10-16 4:27 ` backreferences Kurtis Rader
2015-10-16 5:42 ` backreferences Ray Andrews
2015-10-16 5:05 ` backreferences Bart Schaefer
2015-10-16 5:28 ` backreferences Bart Schaefer
2015-10-16 5:46 ` backreferences Ray Andrews
2015-10-16 11:14 ` backreferences Peter Stephenson
2015-10-16 5:36 ` backreferences Ray Andrews
2015-10-16 12:35 ` backreferences Bart Schaefer
2015-10-16 16:37 ` backreferences Ray Andrews
2015-10-17 3:33 ` backreferences Bart Schaefer
2015-10-17 5:16 ` backreferences Ray Andrews
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