I'm using Text::Balanced for an implementation of template like system. I've gotten it to work exactly as it's supposed to, except it's horribly slow. I'm wondering if I'm doing something wrong. The idea is that given some text marked up like so: 
This is text 0.
<SECTION[1]>
This is text 1.
</SECTION>
This is text 0.
<SECTION[2]>
This is text 2.
</SECTION>

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We specify which section tags to show and which to delete. So, if I called this function on the above text with only section 1 set to show, I'd get: 
This is text 0.
This is text 1.
This is text 0.

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Here's my implementation/test program: 
#!/usr/bin/perl -d:DProf

use Carp;
use Text::Balanced;

our $extract_section_tag  =  Text::Balanced::gen_extract_tagged( '<SEC
+TION\[([^\]]+)\]>\n?', '</SECTION>\n?', '[\S\s]*?(?=<SECTION\[)' );

my $page;
$page .= "This is some filler.\n" x 20000;
$page .= "<SECTION[test1]>\n";
$page .= "This is some filler.\n" x 20000;
$page .= "</SECTION>\n";
$page .= "This is some filler.\n" x 20000;
$page .= "<SECTION[test2]>\n";
$page .= "This is some filler.\n" x 20000;
$page .= "</SECTION>\n";
$page .= "This is some filler.\n" x 20000;

print "Calling process_section.  Length of page=[" . length($page) ."]
+\n";
my $newpage = process_section($page, {test1 => 1});
print "Done.  Length of newpage=[" . length($newpage) ."]\n";

sub process_section {
    my ($page, $hashref) = @_;

    my ($tag_section, $post, $pre, $tag_open, $content, $tag_close, @i
+nfo);

    my $return = '';

    while ( @info = $extract_section_tag->($page) ) {
        ($tag_section, $post, $pre, $tag_open, $content, $tag_close) =
+ @info;

        if (! (defined $tag_section && length $tag_section) ) {
            if ($post =~ m/<SECTION\[/) {
                my $excerpt = substr($post, 0, 100);
                print STDERR "\n";
                Carp::carp("Warning: Unbalanced SECTION tags.  Fix the
+ template! Error near: $excerpt\n");
            }
            last;
        }

        my $show = 0;
        if ($tag_open =~ m/<SECTION\[(.*?)\]>/) {
            $show = 1 if (exists $hashref->{$1});
        }

        if ($show && $content =~ m/<SECTION/) {
            $content = process_section($content, $hashref);
        }

        $return .= $pre . ($show ? $content : '');
        $page = $post;
    }

    $return .= $post;
    return $return;
}

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The above code takes over 2 seconds to run on my system, and it gets even worse as the page it's processing gets larger. How can I improve the speed of this? I'm using Text::Balanced v2.0.0, which fixes the issue of a $& variable slowing down all regexps.

In reply to Am I using Text::Balanced correctly? Speed issues. by solri1

Title:
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