This is interesting. I tried this in a couple XQuery parsers and they all report an error
1 treat as xs: untypedAtomic Reading up on "treat as" is a bit confusing to me. "cast as" works as defined 1 cast as xs: untypedAtomic And there is a lot of verbage in XQuery 3 about casting to untypedAtomic but I cant find a thing about treat as. And in the XSD type system described here : http://www.w3.org/TR/xmlschema-2/ I cant find xs:untypedAtomic anywhere which makes me think it is not a type anything is actually derived from... thus reading about 'treat as' " Unlike cast, however, treat does not change the dynamic type<http://www.w3.org/TR/2013/CR-xquery-30-20130108/#dt-dynamic-type> or value of its operand. Instead, the purpose of treat is to ensure that an expression has an expected dynamic type at evaluation time." So if xs:untypedAtomic is not the base type of anything then it makes sense that treat as will fail ---------------------------------------- David A. Lee [email protected]<mailto:[email protected]> http://www.xmlsh.org From: [email protected] [mailto:[email protected]] On Behalf Of Michael Kay Sent: Sunday, January 20, 2013 7:29 PM To: [email protected] Subject: Re: [xquery-talk] treat as On 20/01/2013 21:47, Michael Sokolov wrote: I'm not sure what the following expression ought to return: declare namespace local="http://localhost/";<http://localhost/>; declare function local:minus($x){ -($x treat as xs:untypedAtomic?) }; local:minus(local:minus(1)) At first I naively *thought* it would return 1 Saxon 9.4.0.3 returns the empty sequence I haven't tried 9.4.0.3, but 9.4.0.6 says: Error on line 3 of test.xq: XPDY0050: Required item type of value in 'treat as' expression is xs:untypedAtomic Query processing failed: Run-time errors were reported Michael Kay Saxonica
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