RE: [xsl] surprised about the results of a filter expression in XSLT2.0

["Michael Kay" <mike@xxxxxxxxxxxx>]

It's actually giving different results under Saxon-B and Saxon-SA (the join
optimizer in Saxon-SA is kicking in and getting something wrong). I'll look
into it.

Michael Kay
http://www.saxonica.com/
 

> -----Original Message-----
> From: alan.painter@xxxxxxxxx [mailto:alan.painter@xxxxxxxxx] 
> Sent: 11 May 2006 17:30
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: [xsl] surprised about the results of a filter 
> expression in XSLT2.0
> 
> I'm surprised to see that a filter expression, applied in 
> this case to a variable, produces more elements in the result 
> than there are elements in the variable.  In this case, it 
> produces the cartesian product of the number of elements in 
> the variable and the number of combinations in the list that 
> comprises the predicate.  I'm assuming that this is normal.
> Where can I find this behavio(u)r described in the XSLT spec? 
>  Thanks for any pointers.
> 
> In Saxon 8.7.1 (perhaps elsewhere but haven't tested), in the 
> below stylesheet, the instruction
> 
>       <xsl:copy-of select="$idElements[@id=$hrefs]"/>
> 
> produces
> 
>    <idElement id="_123"/>
>    <idElement id="_123"/>
>    <idElement id="_123"/>
>    <idElement id="_456"/>
>    <idElement id="_456"/>
>    <idElement id="_456"/>
> 
> whereas the instruction
> 
>       <xsl:copy-of select="$idElements[@id=distinct-values($hrefs)]"/>
> 
> produces
> 
>    <idElement id="_123"/>
>    <idElement id="_456"/>
> 
> Here's the stylesheet
> 
> <?xml version="1.0" encoding="UTF-8"?>
> 
> <xsl:stylesheet xmlns:xs="http://www.w3.org/2001/XMLSchema";
>                 xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
>                 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
>                 version="2.0">
> 
>       <xsl:output method="xml" encoding="ISO-8859-1" indent="yes"/>
> 
>       <xsl:variable name="testdoc">
>             <root>
>                   <refElement name="element1"> <ref 
> href="_123"/> </refElement>
>                   <refElement name="element2"> <ref 
> href="_123"/> </refElement>
>                   <refElement name="element3"> <ref 
> href="_123"/> </refElement>
>                   <refElement name="element4"> <ref 
> href="_456"/> </refElement>
>                   <refElement name="element5"> <ref 
> href="_456"/> </refElement>
>                   <refElement name="element6"> <ref 
> href="_456"/> </refElement>
>                   <idElement id="_123"/>
>                   <idElement id="_456"/>
>                   <idElement id="_789"/>
>             </root>
>       </xsl:variable>
> 
>       <xsl:variable name="idElements" select="$testdoc//idElement"/>
> 
>       <xsl:template match="/">
>             <xsl:apply-templates select="$testdoc" mode="inTestDoc"/>
>       </xsl:template>
> 
>       <xsl:template match="*" mode="inTestDoc">
>             <xsl:variable name="hrefs" as="xs:string*"
> select="$testdoc//@href"/>
>             <xsl:copy>
>                   <!-- Case 1 -->
>                   <xsl:copy-of select="$idElements[@id=$hrefs]"/>
>                   <!-- Case 2 -->
>                   <!-- <xsl:copy-of
> select="$idElements[@id=distinct-values($hrefs)]"/> -->
>             </xsl:copy>
>       </xsl:template>
> 
> </xsl:stylesheet>
> 
> Output of case 1:
> 
> <?xml version="1.0" encoding="ISO-8859-1"?> <root 
> xmlns:xs="http://www.w3.org/2001/XMLSchema";
>       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";>
>    <idElement id="_123"/>
>    <idElement id="_123"/>
>    <idElement id="_123"/>
>    <idElement id="_456"/>
>    <idElement id="_456"/>
>    <idElement id="_456"/>
> </root>
> 
> Output of case 2:
> 
> <?xml version="1.0" encoding="ISO-8859-1"?> <root 
> xmlns:xs="http://www.w3.org/2001/XMLSchema";
>       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";>
>    <idElement id="_123"/>
>    <idElement id="_456"/>
> </root>
> 
> -alan
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