[Zope] Intersection/Union of ZCatalog result sets

[Jonathan Hobbs]

I have found some old references to proposals for implementing the ability
to combine (intersection, union) the result sets from multiple ZCatalog
queries.  Does anyone know if the ability to combine two or more 'lazy
result sets' has been implemented?

Hunting through the zope source code the only similar routines I could find
were in the BTrees and ZCTextIndex code, but they deal with
intersection/union of BTrees (not lazy result sequences).  As an
alternative, is there any way to get ZCatalog search results in 'BTree' form
instead of lazy results?

Thanks,

Jonathan