[Zope] building a revisitable object list???

[Tres Seaver]

Kevin Dangoor <kid@kendermedia.com> wrote

> ----- Original Message -----
> From: "Darran Edmundson" <dee124@rsphy1.anu.edu.au>
> To: <zope@zope.org>
> Sent: Sunday, February 13, 2000 9:40 AM
> Subject: [Zope] building a revisitable object list???
> 
> > I'm using nested <dtml-in> blocks to descend two levels
> > into a portion of my ZODB.  I'm only interested in the
> > leaf nodes.  However, rather than act on them while
> > "visiting", I want to conditionally store a reference to them
> > in a python list so that I can visit any leaf later on.
> 
> This should probably be done in a PythonMethod. It's sooooo much cleaner. I
> used to do this kind of thing in DTML, because it was too much of a pain to
> make an ExternalMethod. With PythonMethods, I find it so much more user
> friendly to write this kind of logic directly in python.
> 
> > I'll make it clear with a pared-down example.
> >
> > root
> >   folder1
> >     subfolder1a
> >     subfolder1b
> >   folder2
> >     subfolder2a
> >
> > I want to build a list such that I can visit various
> > subfolders without having to search them out.
> 
> So the subfolders all have unique names? If so, you can build a hash:
> 
> leaves = {}
> 
> for folder in objectValues('Folder'):
>   for leaf in folder.objectValues('Folder'):
>     leaves.update({leaf.id : leaf})
> 
> After this, you can just do leaves['subfolder1a'] to get the actual
> subfolder1a object.

That 'leaves.update(..}' is a really ugly workaround to the fact that
PythonMethods won't allow the "natural" dictionary manipulation: 'leaves[
leaf.id ] = leaf'.  While I understand not wanting to allow key replacement in
"global" dictionaries, can we lose this restriction for "local" ones?  (OTOH, we
need to look at potential security issues around the use of update(), too).

Tres.
-- 
=========================================================
Tres Seaver         tseaver@palladion.com    713-523-6582
Palladion Software  http://www.palladion.com