Re: Newbie question list: Was The perverse vibe of lua-l

[Axel Kittenberger <axkibe@...>]

Just a meta-message about the discussion.

Did you notice how this thread went from
"lets split the mailling list" to
"how about faqs" to
"how regular are luas regular expressoin?"

I suppose that alone should be a case why topic splitting into lists
is not a good idea in practice.

On Thu, Jan 27, 2011 at 1:20 PM, Tony Finch <dot@dotat.at> wrote:
> On Wed, 26 Jan 2011, 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/
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>
>