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Precedence rules for QuantifiedExpr - OrExpr - AndExpr

From: Peter Coppens <pgp.coppens@pandora.be>
Date: Fri, 19 Dec 2003 16:36:44 +0100
To: <www-ql@w3.org>
Message-Id: <20031219153645.36A53144EC@dr-nick.w3.org>

All,

Looking at the XQuery spec, I am somewhat surprised by the consequences of
the precedence rules for QuantifiedExpr - OrExpr and AndExpr 

What I mean is:

Take the query

for $x in (1,2,3)
where 
  some $y in (1,2) satisfies 1 = $y and $y = 1
return $x
 
Which, I think, is equivalent to 
 
for $x in (1,2,3)
where 
  some $y in (1,2) satisfies (1 = $y and $y = 1)
return $x
 
But now take the query
 
for $x in (1,2,3)
where 
  some $y in (1,2) satisfies 1 = $y or $y = 1
return $x
 
 
Which, I think, is equivalent to 
 
for $x in (1,2,3)
where 
  (some $y in (1,2) satisfies 1 = $y) or $y = 1
return $x

I find that rather confusing.

So I guess I have the following questions 

(1) is the above interpretation correct?
(2) is this a deliberate choice and if yes, are there any motivations for
that decision that can be shared?
(3) would it not be possible to add an extra level of precendence where the
OrExpr comes to sit between QuantifiedExpr and AndExpr, or would that
propagate to have other side effects?

Thanks,

Peter
Received on Friday, 19 December 2003 10:49:19 UTC

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