sub serial {
    join(', ', @_[0..$#_-1]) . 
        (@_>2 ? ',':'' ) . 
            (@_>1 ? (' and ' . $_[-1]) : $_[-1]);
}

##</code><code>##

  my @primate = qw( sifaka gibbon tarsier langur );
  print "Endangered primates: ", serial(@primate), ".\n";

##</code><code>##

# in some parent formatting, template processing module
use Template;   # not actually using it in the code here
use Template::Stash;
$Template::Stash::LIST_OPS->{ serial } =
    sub {
        my @list = @{ +shift || [] };
        join(', ', @list[0..$#list-1]) .
            (@list>2 ? ',':'' ) .
            (@list>1 ? (' and ' . $list[-1]) : $list[-1]);
    };
##</code><code>##

Hey, Joe. Where you going with that 
[% user.ListOfItems.serial %] in your hand?