sub list {
   if (defined(ref($_[0])) && ref($_[0]) eq 'ARRAY') {
      return @{ $_[0] };
   } else {
      return $_[0];
   }
}

foreach $products (list($file->{product}))    {
    print "Widget: " . $products->{title} ." \n";
    print "Rating: " . $products->{rating} . "\n";
    print "  Cost: " . $products->{cost} . "\n";
    print "Colors: " . join(', ', list($products->{color}))."\n\n";
}