Re: Newbie question list: Was The perverse vibe of lua-l
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- Subject: Re: Newbie question list: Was The perverse vibe of lua-l
- From: Tony Finch <dot@...>
- Date: 2011年1月27日 12:20:15 +0000
On 2011年1月26日, Tim Mensch wrote:
>
> > %bxy, where x and y are two distinct characters; such item matches
> > strings that start with x, end with y, and where the x and y are
> > balanced.
>
> I hadn't run across that before, and it's cool. As Tony mentions, Perl
> has a LOT of extensions, and I don't care enough to check, but I
> wouldn't be surprised if it does support something similar.
You have to do it using explicit recursion, e.g. the (?0) syntax or the
(??{ code }) syntax.
http://perldoc.perl.org/perlre.html#%28??{-code-}%29
> But as far as I'm concerned, what "grep" accepts is the canonical
> "regular expression", and I'm sure grep doesn't support that. Another
> reason why Lua is just more awesome. ;)
I prefer egrep syntax because they have fewer backslashes.
Also, POSIC BREs (grep style) are not proper reegular expressions because
they don't have an alternation operator and they have a backref operator.
POSIX EREs (egrep style) are proper regular expressions in the
mathematical sense.
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html
Tony.
--
f.anthony.n.finch <dot@dotat.at> http://dotat.at/
HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7,
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- References:
- The perverse vibe of lua-l, Dirk Laurie
- Newbie question list: Was The perverse vibe of lua-l, Steve Litt
- Re: Newbie question list: Was The perverse vibe of lua-l, Javier Guerra Giraldez
- Re: Newbie question list: Was The perverse vibe of lua-l, Steve Litt
- Re: Newbie question list: Was The perverse vibe of lua-l, Tim Mensch
- Re: Newbie question list: Was The perverse vibe of lua-l, Miles Bader
- RE: Newbie question list: Was The perverse vibe of lua-l, Aaron Brown
- RE: Newbie question list: Was The perverse vibe of lua-l, Aaron Brown
- Re: Newbie question list: Was The perverse vibe of lua-l, Miles Bader
- Re: Newbie question list: Was The perverse vibe of lua-l, Peter Cawley
- Re: Newbie question list: Was The perverse vibe of lua-l, Tony Finch
- Re: Newbie question list: Was The perverse vibe of lua-l, Tim Mensch