String xsl:param as XPath expression

Vx · September 5th, 2006, 09:22 AM

I have global parameter containing string of XPath expression
<xsl:param name="ItemQuery" select="'//Item'" />
I need to use this parameter later as a value for select attribute:

Code:

<xsl:for-each select="$ItemQuery" >            
  <xsl:call-template name="item" />
</xsl:for-each>

But having used syntax above I got an error 'ItemQuery' must evaluate to a node list.
What should I do to use string literal '//Item' as XPath expression for select attribute?
Thanks

joefawcett · September 5th, 2006, 09:35 AM

Using standard XSLT you can't. There are three options

Use an extension function, Saxon provides one; I think it's called saxon:parse but you'll have to check.
If the XPath is simple you can often rewrite to something like //*[name() = $ItemQuery]; this is okay if you're just passing an element name.
Pass a node-set instead of a string as the parameter; how you do this depends on the processor.

--

Joe (Microsoft MVP - XML)

mhkay · September 5th, 2006, 09:48 AM

Standard XSLT doesn't allow you to construct an XPath expression as a string at run-time. But some products have extension functions (usually called xx:eval() or xx:evaluate()) that meet this requirement.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

Vx · September 5th, 2006, 09:57 AM

Joe and Michael,
Thank you, I got the point.

joefawcett · September 5th, 2006, 10:18 AM

Quote:

quote:Originally posted by mhkay
Standard XSLT doesn't allow you to construct an XPath expression as a string at run-time. But some products have extension functions (usually called xx:eval() or xx:evaluate()) that meet this requirement.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

Then it'll be saxon:evaluate then :)

--

Joe (Microsoft MVP - XML)