Re: gnus-glimpse.el -- search a newsgroup using glimpse

[Kai Grossjohann <grossjohann@charly.cs.uni-dortmund.de>]

>>>>> Lars Magne Ingebrigtsen writes:

  Lars> The search languages the different backends provide would be
  Lars> quite varied, and I don't presently have any clear idea of how
  Lars> Gnus should specify the searches...

Specifying a syntax for queries that

  - the average user can understand,
  - is expressive enough to cover interesting cases, and
  - doesn't produce unmanageably long queries

is certainly not simple to think up.  Hm.  Infoseek uses a format that
might be workable.  An example:

    widgets +subject:foo from:john -subject:re

This query would search for "widgets" anywhere in a mail, "foo" in the
subject header, "john" in the from header, and "re" in the subject
header.  The search is on a best-match basis, but the "+" indicates
that "foo" *must* be in the subject and the "-" indicates that "re"
*may not* be in the subject.  For the other elements of the query, a
message that contains the word would tend to be ranked higher that a
message that doesn't.

The nnchoke-search functions I suggested before would have to accept a
string in the above format and do something meaningful with it.  For
some search engines, a lot of the semantics would have to be left
out.  For instance, I don't think field searches would be feasible
with glimpse, so there a query "subject:foo" would have to be
equivalent to just "foo".

Hm.  I see that I have assumed that the search engine does ranking.
(Documents that better match the query are ranked higher; to be exact,
documents that have a higher probability of being relevant to the
user's information need are ranked higher.)  Maybe we have to leave
this one out in the first version so there would be no difference when
specifying "+".

kai
-- 
Life is hard and then you die.