AFAIK, Jim wants this for Zope3 for some time now. The idea is to implement this with named adapters.
The framework is implemented, as are one or two examples, IIRC...
The question remains how to implement this in Zope2 as we don't have adapters there.
The implementation in Zope 3's TALES engine doesn't rely on Adapters, take a look :-)
Zope-Dev maillist - [EMAIL PROTECTED]
** No cross posts or HTML encoding! **
(Related lists - http://mail.zope.org/mailman/listinfo/zope-announce