$ perl -MSet::IntSpan -le 'print Set::IntSpan->new("1-10")->complement->run_list'
(-0,11-)

##</code><code>##

use Set::IntSpan;
my $set = Set::IntSpan->new('3-12,25-30,42');
for ( my $el=$set->first; defined $el; $el=$set->next ) {
	print "$el\n";
}