[Zope-CMF] Topic ANDing

[Tres Seaver]

Loren Stafford wrote:

> I tried to do this on my Zope 2.3.2 installaion, but things still got ORed. 
> 
> I see support for texindex_operator, but not for a field index operator.
> 
> Does that mean there is no way to AND Subject criteria on Zope 2.3.x?
>
>>What you require is not a "drop-in index";  standard keyword indexes
>>(of which the Subject index is one) have this feature, but the
>>CMFTopic.ListCriterion does not expose it.  We would need to add
>>a property to ListCriterion to track the "operator" desired, and
>>then modify its 'getCriteriaItems' method to add that value, using
>>field + "_operator" as its key.

I just looked at my Zope 2.3 checkout -- you are correct, the KeywordIndex
there does not know from 'operator'.

You could perhaps implement a "hammer-in" index (unlike pluggable indices,
it requires some violence to get it installed) which did what you want
in Zope 2.3.  This would either require a "monkey patch" to
$ZOPE_HOME/lib/python/Products/ZCatalog/Catalog.py, as its 'addIndex'
hardwires the list of possible indeex types, or else reaching into the
catalog's 'indexes' dict and installing your notional AndingKeywordIndex
directly.  The AndingKeywordIndex would override '_apply_index', replacing
the use of 'union' with 'intersection'.

Tres.
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Tres Seaver                                tseaver@zope.com
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