RE: [xsl] Custom function in template match predicate

["Michael Kay" <mike@xxxxxxxxxxxx>]

Not sure why you are writing a custom function when resolve-QName already
exists to do this job. 

If your code was schema-aware, of course, the QName resolution would happen
automatically:

<xsl:template match="schema-element(foo)[@format eq QName('fmt:type1')]">

As Wendell pointed out, the reason it doesn't work is the "= true".

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

> -----Original Message-----
> From: Ian Stokes-Rees [mailto:ijstokes@xxxxxxxxxxxx] 
> Sent: 23 September 2008 18:19
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: [xsl] Custom function in template match predicate
> 
> 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