if (lc($_[$n]) eq 'print')
			{ $this->{'sub'}->[$n] = ($n==0 ? \&_print0 : \&_print1); }

.. a few lines down ..

sub _print0
# Prints a Turtle triple.
{
	my $this    = shift;
	my $element = shift;
	my $subject = shift;
	my $pred    = shift;
	my $object  = shift;
	
	printf("# Triple on element %s.\n", $element->nodePath);
	
	printf("%s %s %s .\n",
		($subject =~ /^_:/ ? $subject : "<$subject>"),
		"<$pred>",
		($object =~ /^_:/ ? $object : "<$object>"));
}

.. and so on ..