[xsl] Custom function in template match predicate

Subject: [xsl] Custom function in template match predicate
From: Ian Stokes-Rees <ijstokes@xxxxxxxxxxxx>
Date: Tue, 23 Sep 2008 13:18:57 -0400
Hi,

I currently have some very unwieldy predicates showing up in lots of xsl:template/@match statements, of the form:


<xsl:template match=" foo[ substring-after(./@format,':') = 'type1' and namespace-uri-for-prefix(substring-before(./@format,':'),.) = 'http://example.com/schemas/formats' ]">


which aim to match different <foo> elements based on the @format QName value, e.g.:



<table xmlns:fmt='http://example.com/schemas/formats'> <foo format="fmt:type1">2008-09-23</foo> <foo format="fmt:type2">9/23/08</foo> </table>


and which do QName expansion so the user can choose the prefix.


I would like to replace the "match" statement with a simplified custom function of the form:


<xsl:template match="foo[ my:test('type1',.) = true ]">



where my:test is defined as:



<xsl:function name="my:test">
<xsl:param name="fmtcode"/>
<xsl:param name="context"/>
<xsl:choose>
<xsl:when test="substring-after($context/@format,':') = $fmtcode and
namespace-uri-for-prefix(substring-before($context/@format,':'),$context)
= 'http://example.com/schemas/formats' ">
<xsl:value-of select="boolean(1)"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="boolean(0)"/>
</xsl:otherwise>
</xsl:choose>
</xsl:function>



The problem is, this doesn't work with Saxon8B. Would others expect this to work with different XSLT v2.0 processors? Is there some way to get this to work with Saxon8B?


Cheers,

Ian

--
Ian.Stokes-Rees@xxxxxxxxxxxx +1 (617) 418-4168
SP Metric Limited, Technology Consulting

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