use Text::Balanced qw/gen_extract_tagged/;

my $text = q{hereiam[[one[[foo]]bar]]baz[[two]][[three]]wwhat};
my $parser = gen_extract_tagged "\Q[[",
                                "\Q]]",
                                qr/.*?(?<!\[\[)(?=\[\[)/,
                                { bad => [ "\Q[[" ] };
while (($extracted, $remainder) = $parser->($text)
       and $remainder ne $text) {
 print "$extracted\n";
 $text = $remainder;
}