Re: TreeVocabulary in zope.schema.vocabulary

Hi Souheil

On Wed, 2012-01-25 at 18:56 +0100, Souheil CHELFOUH wrote:
> A quick note :
> 
> This quite an advanced vocabulary, why not make another package with a
> dependency on zope.schema ?
> I don't quite see the point to have that in the "core".

Ok, Charlie also expressed his reservations. I'll put it in a different
package then.

I'm not too sure what to name it though. For example, under what
namespace? zope or z3c?

I'm guessing zope.vocabulary, or rather zope.treevocabulary?

> Furthermore, for the dict class in use in the vocabulary, you could
> add a "factory" class that can be overriden easily.
> That would allow people with OrderDict capabilities to use them
> without having to re-sort later on.

Could you please elaborate on what you mean?

If I create a factory class to create TreeVocabulary instances, how will
overriding that factory (without creating a separate
SortableTreeVocabulary) allow people to use OrderedDict?

Incidentally, I came upon this: http://pypi.python.org/pypi/ordereddict
which provides the OrderedDict to Python 2.4 to 2.7

I think it might make sense to just subclass OrderedDict and implement
an ordered tree from the start.

> By the way, good work on that, it's something that is often needed in
> advanced forms. I'll make sure to try it.
> Thank you for the effort.

Thanks! Much appreciated.

J-C



> 
> - Souheil
> 
> 2012/1/25 Marius Gedminas <[email protected]>:
> > On Wed, Jan 25, 2012 at 01:55:28AM +0200, Jan-Carel Brand wrote:
> >> On Wed, 2012-01-25 at 00:52 +0200, Marius Gedminas wrote:
> >> > On Tue, Jan 24, 2012 at 07:34:03PM +0200, Jan-Carel Brand wrote:
> >> > > I now subclass PersistentMapping instead of SimpleVocabulary, so this is
> >> > > not an issue anymore.
> >> >
> >> > Ok.  But why Persistent?  None of the other vocabularies are
> >> > persistent...
> >>
> >> Yeah, using PersistentMapping was a mistake, firstly because persistence
> >> is not necessary and secondly because it introduces a dependency on
> >> Persistence.
> > <...>
> >> > > I've changed the TreeVocabulary to subclass from PersistentDict. So the
> >> > > vocabulary itself now acts as a dict.
> >> >
> >> > So is it PersistentMapping or PersistentDict then?  ;)
> >>
> >> It was first the one, and then the other :)
> >
> > For extra fun: one is an alias for the other in newer ZODB versions.
> >
> >> > > > > Perhaps I should rephrase :)
> >> > > > >
> >> > > > > I would like my changes to be merged with the zope.schema trunk. The
> >> > > > > tests I've added provide 100% coverage of the TreeVocabulary code.
> >> > > > >
> >> > > > > I would just like someone to sign it off.
> >> > > >
> >> > > > -1 because of the concerns above.
> >> > >
> >> > > Fair enough. Have your concerns been addressed properly?
> >> >
> >> > Thank you, yes.
> >> >
> >> > I'm still wondering about the possibility of ordered trees.
> >>
> >> Python 2.7 has an OrderedDict class in the collections module:
> >> http://docs.python.org/dev/whatsnew/2.7.html#pep-0372
> >
> > Yes.  And if I pass an OrderedDict to your .fromDict(), it will be
> > discarded and all the items inserted into a regular dict, forgetting
> > their original order.
> >
> > But anyway, I'm fine with you saying "explicit ordering is not
> > supported; it's up to the widget to sort each tree level appropriately".
> > In the class docstring, say.  ;-)
> >
> >> > And I'm -1 for subclassing PersistentMapping.  It may tempt people into
> >> > storing tree vocabularies in the ZODB, and then maybe even modifying
> >> > them.  And you have plenty of non-persistent dicts in the internal
> >> > structure.
> >> >
> >> > I think it would be better to subclass a regular dict, and document that
> >> > you ITreeVocabulary is a dict-like object by making it inherit
> >> > IEnumerableMapping.
> >>
> >> Thanks for the suggestion, I did that.
> >
> > I've no objections remaining (other than that little thing about
> > explicit ordering).
> >
> > Marius Gedminas
> > --
> > http://pov.lt/ -- Zope 3/BlueBream consulting and development
> >
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