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RE: M.Kay XSLT book, p. 120 Curly braces question
- To: "'xsl-list at mulberrytech dot com'" <xsl-list at mulberrytech dot com>
- Subject: RE: M.Kay XSLT book, p. 120 Curly braces question
- From: Kay Michael <Michael dot Kay at icl dot com>
- Date: Mon, 31 Jul 2000 12:13:33 +0100
- Reply-To: xsl-list at mulberrytech dot com
> I would like to use a
> variable or parameter as part of an XPath expression.
> However, whereas I can use variables in constructions such as
> $doc/FeatureSet[$i]/Feature[$j], where $doc is a nodeset generated by
>
> <xsl:variable name="doc" select="document(@FeatureFile)"/>
>
> I cannot use a construction like $doc//$mypointer, where
> $mypointer has the value 'FeatureSet[2]/Feature[4]'.
To quote my response to another question today:
XSLT 1.0 doesn't allow you to construct XPath expressions, or parts of
expressions, from strings or variables at run-time.
You can sometimes work round it using name(), e.g.
select='document("EZ722.xml")/*[name()=$element]'
But that doesn't work in this case. Saxon has a more powerful workaround:
the saxon:evaluate() extension function. Here you could write:
select="saxon:evaluate(concat('$doc/', $mypointer))"
> In my xml file which describes my data, I want to include a
> reference to the original data that was used in the calculation.
I think this is the classic use-case that justifies a feature such as
saxon:evaluate().
Mike Kay
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