#!/usr/bin/perl
use warnings;
use strict;

my @ranges = ('5-10', '14-18', '22-27');
my $in     = '1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20-21-22-23-24-25-26-27-28-29-30';
my $exp    = 'A-A-A-A-X-X-X-X-X-X-B-B-B-X-X-X-X-X-A-A-A-X-X-X-X-X-X-B-B-B';

use Test::More tests => 1;

my $replace = 'A';
my $out     = $in;
my $in_range;

while ($in =~ /([0-9]+)/g) {
    my $i = $1;
    if (! $in_range && grep /^$i-/, @ranges) {
        $in_range = 1;
    }
    $out =~ s/[0-9]+/$in_range ? 'X' : $replace/e;
    if ($in_range && grep /-$i$/, @ranges) {
        undef $in_range;
        $replace = $replace eq 'A' ? 'B' : 'A';
    }
}

is $out, $exp;