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Re: FS quantifiers

From: Mary Fernandez <mff@research.att.com>
Date: 17 May 2004 18:34:37 -0400
To: public-qt-comments@w3.org, plucas@bea.com
Message-Id: <1084833276.1964.27.camel@squeak.research.att.com>


> 	This is a request for the rationale as to why the quantifiers
> 	for "()" and "none" changed between Aug 2002 and May 2003.  In
> 	Aug 2002:
> 
> 		quantifier(())   = 0
> 		quantifier(none) = 0
> 
> 	In May 2003, this changed to:
> 
> 		quantifier(())   = ?
> 		quantifier(none) = 1
> 
> 	Why?  The current version seems rather odd.  Why should
> 	quantifier(none) be 1?
> 
> 	- Paul
> 	  BEA Systems, Inc.

A little detective work indicates that this has been the definition
since May 2003:
http://www.w3.org/TR/xquery-semantics/#jd_prime
http://www.w3.org/TR/2003/WD-xquery-semantics-20030822/#jd_prime
http://www.w3.org/TR/2003/WD-xquery-semantics-20030502/#sec_factor

Returning to Nov 2002, we see the old definition:
http://www.w3.org/TR/2002/WD-query-semantics-20021115/#jd_prime
which was unnecessarily complex.  First, there is no '0' quantifier
in the language, only ?, 1, *, +.  Plus all the entries in
the table for combining the 0 quantifier are redundant 
(e.g., () . 0 = () = () . 1),
so we can just get rid of 0 quantifiers entirely.  Make sense?



-- 
Mary Fernandez <mff@research.att.com>
AT&T Labs - Research
Received on Monday, 17 May 2004 18:34:58 UTC

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