[Zope3-dev] Re: ObjectHub should change data structure

[Philipp von Weitershausen]

Jim Fulton wrote:
> Phillip J. Eby wrote:
> 
>> Just a thought, but given how much work generally has to be done to 
>> associate an object with its context (i.e., path) in Zope, would it be 
>> really such a bad thing to have objects know who their parent(s) are?  
> 
> This is a question that I ask myself regularly. :)

You are not the only one.

>     o Requiring all objects to manage their parents
>       would be intrusive.  Zope 3 wants to avoid any
>       requirements on content objects.

I agree.

Why not adapt the pattern we use with annotations for this? 
IAttributeAnnotatable comes to mind. We could have a 
IAttributeParentAware (please come up with a better name!), in which 
case the machinery is allowed to set __parent__ or whatever else.

We could also have a regular IParentAware interface which defines 
methods like getParent() and setParent() for objects that *would* like 
to manage their parents in some way.

>       <wave member="hands">
>       Perhaps this could be mitigated by permanent
>       decorators.  Such decorators might even be
>       used to avoid mixing in persistence in some cases.
> 
>       That is, when we add an object to a container and the
>       object isn't parent aware, we put it in a decorator that
>       is and we store the decorator in the container.
>       </wave>

That sounds like a good idea and could be the fallback option, if the 
object itself is not and does not want to be parent-aware. Maybe this is 
even the only thing we need, plus it wouldn't be that far from what 
we're doing now.

Philipp