Hi Renaud,
On 5/20/2011 at 1:58 PM, Renaud Delbru wrote:
> As said in
> <http://lucidworks.lucidimagination.com/display/LWEUG/Boolean+Operators>,
> "if one or more of the terms in a term list has an explicit term operator
> (+ or - or relational operator) the rest of the terms will be treated as
> "nice to have.
I am not familiar with Lucid's offerings, so I can't comment on the
documentation you quoted. Note, however, that LucidWorks and Lucene are
different products.
> I would have expected that the default AND operator applies whenever no
> other operators are precised in the query.
>
> For exmaple
>
> cat +dog -fox
>
> Selects documents which must contain "dog" and must not contain "fox".
> Documents will rank higher if "cat" is present, but it is not required."
>
> I would have expected such behaviour, whatever "Default Operator" as
> been defined.
>
> But it seems that I need to use the Default Operator OR to have this
> behaviour, which breaks our current requirement (we want default
> operator AND if no operators are precised in the query).
Restating: you want default AND behavior when the query contains no operators,
and default OR behavior when the query *does* contain operators.
This is not supported by the Lucene QueryParser.
> IS there anyway to achieve this ? Or do I need to extend myself the
> queryparser contrib ?
A workaround may be to simply look for "+" and "-" in the query under one of
the following conditions: preceded either by "(" or " ", or at the beginning of
the string, e.g. using a regex like /(?:^|[\s(])[+-]/, and if you find a match,
use default OR operator, and if not, use default AND operator?
Steve
