use strict;
use warnings FATAL => 'all';

##</code><code>##

sub get_numbers_from_ranges {
    my $spec = shift;

    my %numbers;
    foreach my $x ( split ',', $spec ) {
        if ( $x =~ /(\d+)-(\d+)/ ) {
            $numbers{$_} = undef for $1 .. $2;
        }
        else {
            $numbers{$x} = undef;
        }
    }
    return map { $_ - 1 } sort { $a <=> $b } keys %numbers;
}