note moritz <code>$$self{_id} //= $id;</code> checks the definedness of <c>$$self{_id}</c>, not of <c>$id</c> (as the other suggested snippets do), so it does something completely different (never reset the attribute, instead of prevent assignment of an undefined id). <!-- Node text goes above. Div tags should contain sig only --> <div class="pmsig"><div class="pmsig-616540"> [http://perl6.org/|Perl 6 - the future is here, just unevenly distributed] </div></div> 988494 988606