I've had this lying around. Is it any less painful? 
use warnings;
use strict;

print ranges(2,3,4,10,11,12), "\n";

sub ranges {
    my @vals = @_;
    my $min = $vals[0];
    my $max;
    my @list;
    for my $i (0 .. (scalar(@vals)-2)) {
        if (($vals[$i+1] - $vals[$i]) != 1) {
            $max = $vals[$i];
            push @list, ($min == $max) ? $min : "$min-$max";
            $min = $vals[$i+1];
        }
    }
    $max = $vals[-1];
    push @list, ($min == $max) ? $min : "$min-$max";
    return join ', ', @list;
}

__END__

2-4, 10-12

[download]

I wonder if Set::IntSpan can do this.

In reply to Re: Converting a list of numbers to use a range operator by toolic
in thread [Solved] Converting a list of numbers to use a range operator by FloydATC

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