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RE: Tests for expressions : boolean effective values

From: Howard Katz <howardk@fatdog.com>
Date: Thu, 17 Feb 2005 12:14:29 -0800
To: <andy.seaborne@hp.com>, "RDF Data Access Working Group" <public-rdf-dawg@w3.org>
Message-ID: <JMEJKDCPGHHIANHOMPDBEEDNCKAA.howardk@fatdog.com>

Hi Andy,

What you're saying about EFB is correct. I'm wondering tho what does it -mean- to AND a ?x variable with something? Can you give me an example of when you might want to do that?

Howard

 > -----Original Message-----
 > From: public-rdf-dawg-request@w3.org
 > [mailto:public-rdf-dawg-request@w3.org]On Behalf Of Seaborne, Andy
 > Sent: Thursday, February 17, 2005 11:13 AM
 > To: RDF Data Access Working Group
 > Subject: Tests for expressions : boolean effective values
 > 
 > 
 > 
 > Today, some of us were puzzling over boolean expressions in 
 > XQuery/Xpath and how 
 > they affect SPARQL.  We think that the "boolean effective 
 > values" rules apply in 
 > constraints and I have checked in some tests into 
 > tests/data/Expr2 for this.
 > 
 > "boolean effective values" reference:
 > http://www.w3.org/TR/xquery/#dt-ebv
 > 
 > and it means that:
 > 
 > "AND ?x" is legal.
 > 
 > ?x is true if the value of ?x is:
 > 
 > * boolean and the value of the boolean is true
 > * a string and length(string) > 0
 > * a numeric: number != NaN && number != 0
 > 
 > Anything else is "type error" which means the whole solution is rejected.
 > 
 > 	Andy
 > 
 > 
 > 
Received on Thursday, 17 February 2005 20:36:59 GMT

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