[Zope] Selecting which objects to loop over

[Rafael Cordones Marcos]

Hi,

This is a newbie question but I haven't been able to find an aswer either at 
the ZopeBook nor querying Google.

How do I filter objects in the <dtml-in> tag based on some object property?

For instance, I want to loop over a set of objects in current directory, like, 
say all DTML Document objects that have an id (name) that begins with "tab-".

I have tried with:

<dtml-in expr="objectValues('DTML Document')">
    <dtml-if expr="_.string.find(id, 'tab-') == 0">
          <p>Object title: &dtml-title;</p>
    </dtml-if>
</dtml-in>

But I get a 

Error Type: AttributeError
Error Value: namefind

error.

Help or pointers to docs appreciated.

Thanks for your time!!

/Rafa

-- 
Rafael Cordones Marcos
rcm@sasaska.net
http://www.sasaska.net