Re: [xsl] Selecting from a node-set using variable path

["J.Pietschmann" <j3322ptm@xxxxxxxx>]

gary fong wrote:
> This works:
>  <xsl:variable name="t1" select="$myNodeSet//a/b/c"/>
>
> This doesn't:
>  <xsl:variable name="t2" select="$myNodeSet/$myPath"/>

Ah, this comes up regularly. It's something like doing
  String a="1 + 1";
  int b=1+a;
in Java and expecting this is not only doesn't cause the
compiler to barf but that b is 3 afterwards.

> How do I filter down my node-set based upon some variable
> location path?
For simple cases there are pure XPath solutions, however,
in your case you'll have to use an extension function to
invoke a runtime XPath interpreter, for example
 <xsl:variable name="myPath">/a/b/c</xsl:variable>
 <xsl:variable name="t3"
   select="xx:evaluate(concat('$myNodeset/',$myPath))"/>
The inner concat evaluates to the string
 $myNodeset//a/b/c
which in turn is evaluated as XPath expression.

Um, well, IIRC MSXML does not have exactly such an extension
function, but you can use a bit of JScript code to emulate
this. The EXSLT project at sourceforge should have such code.

J.Pietschmann


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