[Traits] Namespaces(environments?), SystemChangeNotifier, ...

Klaus D. Witzel klaus.witzel at cobss.com
Mon Apr 24 17:23:34 UTC 2006


Hi Roel,

on Mon, 24 Apr 2006 17:48:27 +0200, you wrote:

> Hello,
>
> I am maintaining the SystemChangeNotifier, so I am interested in the  
> discussion.

Thank you for taking care!

> Could you elaborate a bit more on SystemChangeNotifier and name clashes,  
> since I did not quite follow you there.

Now that I reread my posting I see that I should have written "namespace  
separation" instead of "name clashes" when I mentioned  
SystemChangeNotifier. Apologies! But anyways, here is how we stumbled on  
SystemChangeNotifier.

We checked the classes in System-Change Notification (and also class  
ModifiedTraitDefinitionEvent) to find out what happens when the namespace  
of an entity (Class or Traits) is changed. We couldn't find evidence that  
such a change is recognized. So possibly [SystemChangeNotifier  
uniqueInstance allSystemEvents] and #notify:ofAllSystemChangesUsing: do  
not handle such a situation? Perhaps [oldItem environment] and [newItem  
environment] would fit the bill, dunno. In any case, namespace changes (of  
classes and/or traits) seem not to be captured nor reported.

There currently is no urgence for system change notification to take care  
of namespace changes, we can live with the "manual" design+development  
rule: take care with namespaces and system change notification.

But for (multiple) namespaces to be useful painlessly, sooner or later  
support from system change notification is neccessary.

Hope this clarifies a bit.

/Klaus




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