Japhy,
Thanks. These suggestions worked great!
At 01:18 AM 6/30/04 -0400, you wrote:
>On Jun 29, David Arnold said:
>
>>\backans{If $x=y^{2n}$ and $z=y^{3n}_{11}$, then we can substitute
>> to find a solution.}
>>
>>I'd like to scan the file and replace all of these with this format:
>>
>>\begin{answer}
>>If $x=y^{2n}$ and $z=y^{3n}_{11}$, then we can substitute
>>to find a solution.
>>\end{answer}
>
>To match nested things, you probably want to use Regexp::Common, which
>allows you to do that very easily:
>
> use Regexp::Common;
>
> $text =~ s<
> \\ backans {
> ( $RE{balanced}{-parens=>'{}'} )
> }
> ><\\begin{answer}\n$1\n\\end{answer}>xg;
>
>The /x modifier is so that I can have extra whitespace, and the /g
>modifier means "do it globally". The %RE hash is quite magical -- see the
>Regexp::Common docs for an explanation. The module isn't standard,
>though, so you'd have to download it from CPAN yourself.
>
>If you want a stand-alone solution, you can have one if you make use of
>some of Perl's special regex constructs:
>
> my $rx; # must be declared first...
> $rx = qr[
> (?:
> (?> [^{}\\]+ | \\. )
> |
> { (??{ $rx }) }
> )*
> ]xs;
> $text =~ s/\\backans{($rx)}/\\begin{answer}\n$1\n\\end{answer}/g;
>
>Its primary trick is the (??{ ... }) assertion, which evaluates its
>contents as PART of the regex to match. Since its contents are $rx
>itself, it basically creates an automatically deeply-enough nested regex
>for you on the fly.
>
>--
>Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/
>RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/
>CPAN ID: PINYAN [Need a programmer? If you like my work, let me know.]
><stu> what does y/// stand for? <tenderpuss> why, yansliterate of course.
>
>
>
>
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