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Tests for expressions : boolean effective values

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Thu, 17 Feb 2005 19:13:28 +0000
Message-ID: <4214ECD8.7010702@hp.com>
To: RDF Data Access Working Group <public-rdf-dawg@w3.org>

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 19:14:23 GMT

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