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From Chris Hostetter <hossman_luc...@fucit.org>
Subject Re: Standard Parser Behavior
Date Tue, 10 Apr 2007 21:40:54 GMT

: The problem is the grouping operator ( ) and how it works with distributed
: operators, I don't quite get what the specific transformation rules are.

you shouldnt' think if parens as a groiuping operator, you should think of
it as a way to force the explicit creation of a BooleanQuery object.

This is a BooleanQuery containing 6 SHOULD clauses...

	A B C D E F

This is a BooleanQuery contain 2 SHOULD clauses, each containing 3 SHOULD
clauses...

        (A B C) (D E F)

...those two queries will match on the same set of documents, but the
scores will be very different because of the way the coord factor comes
into play for *each* BooleanQuery in the hierarchy.

: I want to assume that:
: +(A B) = +A +B
: -(A B) = -A -B

...in the left side of your "equations" the + and - are meaningless unless
they are part of larger queries ... a + only means that wha comes after it
is a MUST clause of the enclosing boolean query; no enclosing query means
the + is meaningless

This is a BooleanQuery containing two clauses, X which is a SHOULD clause,
and another BooleanQuery which is a MUST clause, that second BoolenaQuery
contains two SHOULD clauses (A and B)...

	X +(A B)

This is a BooleanQuery containing two clauses, X which is a SHOULD clause,
and another BooleanQuery which is a SHOULD clause, that second
BoolenaQuery contains two MUST clauses (A and B)...

        X (+A +B)

...wo while the first query requires A or B match, the second query
requires neither: X is sufficient, or both A and B together are
sufficient.


does this make more sense?



-Hoss


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