investigate upgrading to using AdvancedQuery to query catalog

[Andy Altepeter]

See if it would be possible (and desired) to switch to Dieter's AdvancedQuery product for catalog queries. This should provide _significant_ complexity and code reduction in the filters and possibly viewers, as complete results can be specified using
a single expression, rather than three or four individual catalog queries, as an example, finding the agenda items in a range requires

1) finding all items that start in the range
2) finding all items that end in the range
3) finding all items that start before the range and end after the range

Hopefully, using Advanced query would allow a single expression for this.

But, do we want to add another dependency? And, does AdvancedQuery fit with Silva's transitioning to zope3 technologies?

AQ can be found here: http://www.dieter.handshake.de/pyprojects/zope/AdvancedQuery.html

[Eric Casteleijn (thisfred)]

> Hopefully, using Advanced query would allow a single expression for
> this.

That sounds interesting. But I'm not sure what this adds to normal
catalog queries except readability? I realize they're not pretty, but it
*is* possible to send a complex query to the catalog, right?

> But, do we want to add another dependency? And, does AdvancedQuery fit
> with Silva's transitioning to zope3 technologies?

It looks like this product is firmly in zope2 land, and hasn't been
updated since 2006 (or at least the web page hasn't.) I think there are
a number of new zope3 ways to use the catalog, but I haven't dived in
too deep yet. We should definitely investigate what this product can do
for us, and if it's useful for silva, add it to the dependencies, or
look for zope3 alternatives, or possibly even port this.

[Eric Casteleijn (thisfred)]

> That sounds interesting. But I'm not sure what this adds to normal
> catalog queries except readability? I realize they're not pretty, but it
> *is* possible to send a complex query to the catalog, right?

Ah, it's the added bonus of 'not' and 'or' queries. Those are useful,
and we've been getting request for those in some of our extensions. Do
you know what it does 'under the hood'? Does it just decompose the
advanced query into simple ones and then combine the results? I'm not
100% sure that that's worth a whole product, but I may be overlooking
things, I haven't done much catalog work recently, so I may have blocked
out how painful it really is ;)