order_queue.pl

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

my @inventory = qw(Pallet1 Pallet2);
my @receiving = qw(Pallet3 Pallet4 Pallet5);
my @orders = qw(Order1 Order2 Order3 Order4 Order5 Order6);

my $order;
while ( $order = shift @orders )
{
    while( my $supply = shift @receiving )
    {
        push @inventory, $supply;
    }


    if ( my $supply = shift @inventory ) 
    {
        print "Fulfilling $order with $supply\n";
    }
}