#!/usr/bin/perl

use strict;
use warnings;

my $item = qr /(?:[Aa]|\d+(?:-\d+)?)/;
my $list = qr /^$item(?:,$item)*$/;

while (<DATA>) {
    chomp;
    print "$_: ", /$list/ ? "matches\n" : "does not match\n";
}

__DATA__
1
1-3
a
1,4-6,a
1,4-6,,a
1,4-6,
,1,4-6,a
1,4-6,b
1,4-6-8,a
1,4-a,2
1,4-6,4-6,1234-12,a



1: matches
1-3: matches
a: matches
1,4-6,a: matches
1,4-6,,a: does not match
1,4-6,: does not match
,1,4-6,a: does not match
1,4-6,b: does not match
1,4-6-8,a: does not match
1,4-a,2: does not match
1,4-6,4-6,1234-12,a: matches
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