Re: [xsl] Custom function in template match predicate

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Ian,

Actually the reason this isn't working is has nothing to do with the processor:

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

The predicated expression "my:test('type1',.) = true" is testing the 
value returned by the function to the value of the 'true' element 
child. But there is no foo/true to compare to, hence it's always false.

If you had foo[ my:test('type1',.) = 'true' ] you'd have better luck.

On the other hand, this might be even better:

<xsl:function name="my:test" as="xs:boolean">
   <xsl:param name="fmtcode"/>
   <xsl:param name="context"/>
   <xsl:sequence select="(substring-after($context/@format,':') = $fmtcode)
      and
(namespace-uri-for-prefix(substring-before($context/@format,':'),$context)
       = 'http://example.com/schemas/formats' )/>
</xsl:function>

... and then

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

(That is, instead of generating and comparing a string, simply 
generate a Boolean value.)

The @as element indicating the return type of the function is not 
strictly necessary, but is good practice for several reasons 
including ease of debugging (you will need to declare the xs: 
namespace prefix with the XML Schema namespace).


Cheers,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
17 West Jefferson Street                    Direct Phone: 301/315-9635
Suite 207                                          Phone: 301/315-9631
Rockville, MD  20850                                 Fax: 301/315-8285
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