[Zope] sort=expr

[jpreston@tdg.com.au]

Hello, hope you're all well,

     I want to do this:

<!--#in expr="objectValues(spec='Folder')" sort=expr="_[sort_order]"-->

I think I do anyway. The value of the property sort_order is a string that is
the id of yet another property, and I want to pass that id as the #in "sort"
parameter.

The code above doesn't work of course. How can I pass the result of an expr as a
 parameter? Is it just correct syntax that I'm lacking?

Cheers,
     Josh