#!/usr/bin/perl -w
use strict;
use Regexp::Common;

my $re = qr{ \( (?: (?> [^()]+ ) | (??{ $re }))* \) }x;

my $input = "aa bb cc (dd ee (ff gg (hh) jj) kk)";

print "With module\n";
while ($input =~ m/(\w+|$RE{balanced}{-parens=>'()'})\s*/g) { 
	print "$1\n";
}

print "With recursive RegExp\n";
while ($input =~ m/(\w+|$re)\s*/g) { 
	print "$1\n";
}

__END__
# output: 
With module
aa
bb
cc
(dd ee (ff gg (hh) jj) kk)

With recursive RegExp
aa
bb
cc
dd
ee
ff
gg
(hh)
jj
kk