#!/usr/bin/env perl

use strict;
use warnings;

use constant {
    EXTRACTED => 0,
    SUFFIX => 1,
    PREFIX => 2,
};

use Text::Balanced 'extract_bracketed';

my $delim = '([{<';
my $prefix = qr{[^$delim]*};

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

my ($current, $wanted) = ($string, '');

while (1) {
    my @parts = extract_bracketed($current, $delim, $prefix);

    if (defined $parts[PREFIX]) {
        my ($trimmed_start) = $parts[PREFIX] =~ /^(.*?)\s*$/;
        $wanted .= $trimmed_start;
    }

    if (defined $parts[EXTRACTED]) {
        $current = $parts[SUFFIX];
    }
    else {
        $wanted .= $parts[SUFFIX];
        last;
    }

}

print "$wanted\n";