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Re: Support for boolean queries in apropos

>> The FTS engine of Sqlite supports Boolean queries.  [...]

> I think that general boolean queries are known now to be less
> powerful and useful than everyone supposed that they were 20 or 30
> years ago, so search engines either omit support for boolean
> operators or else do not encourage the use of such operators.

Those are not necessarily related to one another.

I suspect the truth is more like, general Boolean queries are something
most end users are not capable of getting the full benefit from, so
search engines - to the extent that it is fair to consider "search
engines" as a single class - have dumbed down their interface to
something their mass audience _can_ make effective use of.

> Instead, usually you can specify terms that MUST appear in the
> results, and terms that MUST NOT appear, [...]

The set of searches that can be expressed this way is a proper subset
of the set of searches that can be expressed with full-fledged Boolean
operators, so it clearly is not a question of capability.  It may be
partially a question of convenience; it would not surprise me if a
simplified interface that worked this way could cover a substantial
fraction of the queries of interest.

However, for NetBSD's audience, I offer my opinion that deliberately
refusing to provide a fully general interface in favour of a crippled
interface is a Bad Thing, even if the latter happens to be less
confusing to people who can't grasp Boolean logic.  (Providing the
simplified interface is not a bad thing.  Not providing the general
interface is.)

> Is there any reason to believe that boolean operators are more
> suitable for apropos than for other search engines?

Yes.  The target audience is very different, as I noted above.

> ISTR you wrote the other day that terms are not weighted and the
> search results are not ranked?  It seems to me that correcting that
> may improve the effectiveness of apropos more than any other measure.

It also requires inventing an ordering to rank them based on.  While it
may be appropriate for a search engine like Google to ignore the search
terms its product specifies in order to better serve its customers, the
economics of NetBSD's manpage interfaces are..rather different.  Pages
either satisfy the query, in which case there is nothing to rank them
based on, or they don't, in which case they should not be mentioned in
the output at all.

Or am I missing something?

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