[Zope] dtml-tree advice, please

[Brian Withun]

Consider the following situation:
---------------------------------

I have two ZClasses.  One ("Album") is folderish, and serves as a photo
album.  The other ("Photo") isn't and serves as a photo in an Album.  Albums
can contain only Albums and Photos.

I would like to have a dtml-tree represent this hierarchy of Albums and
Photos.

The Question:
-------------

should I use

<dtml-tree branches_expr="objectValues('Album')" ..
<dtml-tree branches=objectValues ..
<dtml-tree branches=tpValues ..
<dtml-tree ???

Things to consider:
-------------------

I need the branches to represent two different meta types, Album and Photo.
If I use branches_expr="objectValues('Album') I'll see the tree rendered
with only Albums, and no Photos shown.

If I use branches=objectValues then I'll see EVERYTHING in the current
folder and, at the top level, peer to the root of any Album hierarchy, there
may be other objects like dtml documents, methods, etc.  I don't want to see
those.

If I use branches=tpValues (..still learning this one..) I'll see any object
(?) in the current folder (?).  This seems to work best in experiment, but
what if I were to define and instantiate some unrelated ZClass and happen to
have one in the current folder with an Album.  I tend to think that it would
be rendered in my dtml-tree with the Albums and Photos..


..If anyone can recommend a source of documentation (be specific, no RTFM's
please) that would help me solve this myself, that, too, would be welcome.

------------
Brian Withun