use warnings; 
use strict;

my $str = '1-5,6a-e,7,10-13';

my @ranged;
foreach ( split ',', $str ) {
  if ( /^(\d+)$/ ) {
    push @ranged, $1;
  } elsif ( /^(\d+)([a-z]+)-([a-z]+)$/ ) {
    push @ranged, map { "$1$_" } $2..$3;
  } elsif ( /^(\d+)-(\d+)$/ ) {
    push @ranged, $1..$2;
  } else {
    die "Don't know how to interpret '$_'";
  }
}

print join "\n", @ranged;