AW: [Zope3-dev] Re: Recursive containment constraints

[dev at projekt01.ch]

Tres Seaver wrote:
> Cc: Dominik Huber
> Betreff: [Zope3-dev] Re: Recursive containment constraints
> 
> 
> Stephan Richter wrote:
> > On Wednesday 15 September 2004 09:01, Dominik Huber wrote:
> > 
> >>Month ago I read the contenttype part of stephan's book. at
> that time
> >>he used setTaggedValue to solve recursive containment constraints:

[...]

> 
> In reality, I think we would be better off moving the constraint
> declarations out of the classes;  that would both remove the "forward 
> reference" problem and make it easy to move to a "containment 
> constraint 
> registry" solution when that became available.
> 
> My biggest reason for wanting this is that the constraints
> are *policy*, 
> which might vary from site to site;  making them intrinsic to 
> the class 
> makes it harder to reuse the container / item classes in a site with 
> different policies.  This consideration would suggest moving the 
> constraint declarations to ZCML, e.g.:
> 
>    <content>
>      ....
>      <contains interface=".interfaces.IFooItem" />
>    </content>
>    <content>
>      ....
>      <container interface=".interfaces.IFooContainer" />
>    </content>

I agree,

This looks much nicer for to write and support.
I also like the idea to put all the variable configuration
stuff out of a class. This makes it more reuseable.

Regards
Roger

Projekt01 GmbH
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