sub listing_out  # override this for your desired output format
 {
 my ($self, $output, $starting, $count, $file, $line, $text)= @_;
 # I guess I really should learn something about the old formatting stuff!
 print {$output} "[$starting] ";
 foreach my $i (0..$count) {
    print {$output} " $self->{PROGRAM}[$starting+$i]";
    }
 print {$output} "\t$text\n";
 }