On Wed, Apr 2, 2008 at 10:48 PM, Randal L. Schwartz <<a href="mailto:merlyn@stonehenge.com">merlyn@stonehenge.com</a>> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
>>>>> "Rob" == Rob Rothwell <<a href="mailto:r.j.rothwell@gmail.com">r.j.rothwell@gmail.com</a>> writes:<br>
<br>
Rob> Is one not supposed to make subclasses of these classes, and if so, why not?<br>
<br>
Generally, your object "has a" collection, but doesn't qualify to be "is a"<br>
collection. If you really want to subclass collection classes, you need<br>
to peer deeply inside the existing classes, and do the right thing.<br>
<br>
It's much easier to implement your object, throw a collection inside, then<br>
implement the parts of the collection protocol that you end up using, starting<br>
with #do:, by delegating those to your inside collection.<br>
</blockquote></div><br>Thanks...I can accept that for now!<br>
<br>
So the behavior I am seeing is to be expected, then? And how would I
have known to expect this? I guess my assumption was that any object
could "extend" any other object!<br>
<br>
Rob<br><br>