[Grok-dev] Re: Performance of OrderedContainer

Gary Poster gary at zope.com
Wed Jun 18 07:26:08 EDT 2008

On Jun 18, 2008, at 4:11 AM, Martijn Faassen wrote:

> Gary Poster wrote:
>> On Jun 17, 2008, at 1:58 PM, Gary Poster wrote:
> [snip]
>>> It can be a drop in replacement for PersistentList in an ordered  
>>> mapping implementation.  The only potential incompatibility I can  
>>> think of is that getting a slice returns an iterator rather than a  
>>> list.
>> Heh, no reply to this,
> [snip caveats with zc.blist in this role]
> Thanks for the feedback, Gary, it is appreciated.

Thanks for your reply.

> The problem is that indeed grok.OrderedContainer does implement the  
> zope.app.container API for ordering, if I'm not wrong.
> Anyway, it would be good if someone could introduce a patch with a  
> more scalable OrderedContainer for Grok *before* the release, as  
> it'll be harder to change internal data structures after people  
> start using it. Not impossible of course, just a lot harder.
> For inspiration, we need to study
> http://svn.plone.org/svn/plone/plone.folder/
> We also need to investigate whether blist could be made to make  
> sense i this role after all.

I just glanced at it.  The API they have (with deltas and such) would  
work well with blist.  The adapter/annotation approach would also  
allow plug-in replacement with a blist approach, should such be desired.

The default implementation of the ordering adapter in this file uses  
PersistentList (see _order near the bottom), so without a different  
adapter, I disagree that this implementation would be appropriate for  
very large collections.

With a different adapter, the API looks good to me, and I like the  
adapter idea for providing ordering.  Unfortunately, the license is  
GPL (http://svn.plone.org/svn/plone/plone.folder/trunk/docs/ 
LICENSE.GPL), so the API itself may be tainted (or not, no idea, but  
my lack of ability to know is part of the point).  I thought code in  
the "plone" namespace was supposed to be ZPL, and "plone.app" was  
GPL?  If it were ZPL, it could potentially just be snarfed up directly  
by grok, IMO.


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