[Zope] dtml-tree and branches

[Anton Gyllenberg]

My namespace gets lost when I try to use the `branches' attribute
of the `dtml-tree' tag.

Example:
	<dtml-tree branches=some_method>
		...
	</dtml-tree>

`some_method' is a dtml-method with the following template:

	<dtml-return "objectValues(['Folder', 'DTML Document', 'File'])">

Rendering the dtml-tree results in:
	Error Type: NameError
	Error Value: objectValues

In this particular case I could use
	brances_expr="objectValues(['Folder', 'DTML Document', 'File'])",
but I plan on augmenting the branch-list with some other objects before
returning from `some_method'. `some_method' works fine if I call it
using
	<dtml-var "some_method(_.None, _)">,
but apparently this is not the way the method is called by the
dtml-tree tag. I also tried
	<dtml-tree branches_expr="some_method(_.None, _)">
Unfortunately, it seems that the namespace where branches_expr is
evaluated doesn't contain the namespace variable `_'.

What am I doing wrong? How can I use a DTML-method to calculate the list
of branches?  By the way, if the branches attribute names a nonexistent
method, the tree ends up empty without triggering any errors. I really
would expect a name error here. Is this a bug?

<dtml-tree branches=no_such_method>...</dtml-tree> -> empty tree.

Yes, and I'm using:
Zope version: Zope 2.1.2 (source release, python 1.5.2, linux2)

Grateful for any help,
--
Anton Gyllenberg <anton@lifix.fi>                        +358-50-3412792