####program.pl
#!/usr/bin/perl
use strict;
use warnings;
use Text::Balanced 'extract_bracketed';

my $delim = '([{<';
my $prefix = qr{[^\Q$delim\E]*};
my $string = 'The use of parentheses (indicates that the (writer [considered] the {information}) less <important—almost> an afterthought).';
my @parts = extract_bracketed($string, $delim, $prefix);
$parts[2]=~s/\s*$//;
print WF1 "pattern:\'$parts[0]\'\n";
print WF1 "rightside of pattern:\'$parts[1]\'\n";
print WF1 "leftside of pattern:\'$parts[2]\'\n";

##</code><code>##

pattern:'(indicates that the (writer [considered] the {information}) less <important—almost> an afterthought)'
rightside of pattern:'.'
leftside of pattern:'The use of parentheses'

##</code><code>##

$string = 'The (use {of}) parentheses (indicates that the (writer [considered] the {information}) less <important—almost> an afterthought).';

Output:
pattern:'(use {of})'
rightside of pattern:' parentheses (indicates that the (writer [considered] the {information}) less <important—almost> an afterthought).'
leftside of pattern:'The'