[Newbies] Changing superclass doesn't "work automatically"

David Zmick dz0004455 at gmail.com
Thu Jul 3 17:13:22 UTC 2008

It seems to me anObslote.. class appears when you delete a class, and it is
still registered somewhere, still has an instance.

You have a root component called WAComponent, and it is registered with
seaside as an application.  You delete the class, but not the application,
the application will no longer have WAComponent as its root component, but
it will be anObsoleteWAComponent.

Is that correct?

On Thu, Jul 3, 2008 at 11:45 AM, Marcin Tustin <mm3 at zepler.net> wrote:

> So, this was unexpected behaviour? Certainly the way that Bert describes
> appears to be what happened in my workspace-based tests.
>  On 7/3/08, Bert Freudenberg <bert at freudenbergs.de> wrote:
>> Am 03.07.2008 um 05:27 schrieb Randal L. Schwartz:
>>    "Marcin" == Marcin Tustin <mm3 at zepler.net> writes:
>>> Marcin> I recently came across a piece of behaviour which is (sort of)
>>> Marcin> understandable, but I wonder if it is how it is supposed to
>>> happen or
>>> Marcin> not. I was running through the potsdam seaside tutorial, and I
>>> change
>>> Marcin> the superclass of one of the objects from Object to WAComponent,
>>> and
>>> Marcin> accepted the change. All the browser tools treated the class as
>>> if its
>>> Marcin> protocol included the messages of WAComponent, but running code
>>> that
>>> Marcin> sent WAComponent messages signaled MessageNotUnderstood.
>>> Are you sure you weren't dealing with a previous instance of your old
>>> class?
>>> I think this kind of a change forks the class def so that new instances
>>> have
>>> the new superclass, but old instances still have the old class and old
>>> superclass (anObsoleteYourClassnameHere).
>>> I could be wrong, but tI think that's how it works.
>> Smalltalk does not work that way. If the class format changed, all
>> existing instance are bulk-migrated to the new class (by creating new
>> instances and doing a forward-become on all of them).
>> - Bert -
>> _______________________________________________
>> Beginners mailing list
>> Beginners at lists.squeakfoundation.org
>> http://lists.squeakfoundation.org/mailman/listinfo/beginners
> _______________________________________________
> Beginners mailing list
> Beginners at lists.squeakfoundation.org
> http://lists.squeakfoundation.org/mailman/listinfo/beginners

David Zmick
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/beginners/attachments/20080703/977da995/attachment.htm

More information about the Beginners mailing list