sub foo {
  return 'hello' unless $_[0];
}
print "First: " . foo(1) . "\n";
print "Second: " . foo(0) . "\n";

##</code><code>##

my $parser_remove = XML::Rules->new(
	rules => [
		_default => 'raw',
		line => sub {
			my ($tag, $attrs, $context, $parents) = @_;
			if ($attrs->{_content} =~ /\s+NOT\s+/) {
				$parents->[-2]{_remove} = 1; # skip the <lines> and set the attribute directly in <address>
			}
			return [$tag => $attrs];
		},
		address => sub {
			return $_[0] => $_[1] unless ($_[1]->{_remove});
		}
	],
	style => 'filter',
);