Thanks for helping me solve this one. In the end I did the following: 1) hacked DocumentTemplate/DT_Util.py to include "filter" in the __builtins__ 2) Installed PythonMethods and called pruneTree with parameter 'self' and content return _.filter( lambda x: x.getProperty('pruneFromTree',0)==0 , self.objectValues(['Folder']) ) 3) The new tag reads <dtml-tree name="Outline" leaves=dtcTemplate branches="pruneTree"> Chris McDonough wrote: |If it's something you want badly (and if you haven't already) add it as |a feature request to the Collector on Zope.org. Once other folks get |past the knee-jerk reaction, maybe it'll sink in as a good thing. In |the meantime, you can add it yourself if you like. Good idea - I'll do that. |Hopefully, you'll be so kind as to forgive me. That's easy - as long as you keep writing HowTos of the same quality as "Zope installation and upgrade" and "Zope enlightenment by understanding object orientation"... :-) |After seeing people post |DTML code to the list that they need debugged that computes pay rates, |has the shape of an arrowhead and scrolls past the maximum character |length of my email client horizontally, I'm a little leery of adding |anything whatsoever to DTML, as I think the rest of the folks at DC |are. Reducing the complexity of DTML is a good thing, however |it can be accomplished. Agreed. You can do some very powerful things with the lamda expressions, but they very quickly become unwieldy if used inappropriately, so I think people are right to be wary. Having said that, any sort of block structured language has the same pitfalls - e.g. Smalltalk, Self, even Java's anonymous classes could be used to detrimental effect. I prefer to leave this stuff to style and convention ("good practice") than prescribe them entirely. Thanks again, Nick.