@array1 = ('a','b','c');
@array2 = ('a','b');
@array3 = ('a','b','c','d');

##</code><code>##

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

use Syntax::Construct qw{ // };

my @array1 = ('a','b','c');
my @array2 = ('a','b');
my @array3 = ('a','b','c','d');

while (@array1, @array2, @array3) {
    print join ', ', map shift @$_ // 'NULL', \@array1, \@array2, \@array3;
    print "\n";
}