Mailing List Archive

I was going to send this answer just to the person who asked the question,
but the return address seems to have been corrupted (unless you're willing
to believe in a machine or domain named "@").

> Date: Thu, 14 Sep 95 19:27:05 BST
> From: Dale Amon <amon@@>
> To: perl5-porters@africa.nicoh.com
> Subject: Re: Fast lexical typing and fun with REXP's
>
> Still interested if there is another way... my
>
> rexp is getting rather longish...
>
> But, I have run across an interesting problem that I've not run into before
> (having not needed quite as complex an overall expression as this)
>
> If you have
> (xxxx (yyyyy))
>
> how do you get the inner value? ie
>
> (xxxxx yyyyy)
>
> would go into $1. Is there anyway to do this if you have to group both, but

I think of this as $<N> recovering the expression corresponding to the N'th
left parenthesis. Here's a simple f'rinstance:

----------
$_ = "first_part second_part";

m/(first_part (second_part))/;
print "\$1 is '$1', \$2 is '$2'\n";

m/((first_part) (second_part))/;
print "\$1 is '$1', \$2 is '$2', \$3 is '$3'\n";
----------

This prints:
----------
$1 is 'first_part second_part', $2 is 'second_part'
$1 is 'first_part second_part', $2 is 'first_part', $3 is 'second_part'
----------


pete peterson
rep@genrad.com
(508)287-7478; Home: (508)256-5829 (Chelmsford, MA)