Re: Passing document fragments as nodsets

Hi Simon,

> I'm having a bit of a struggle with passing a subset of nodes around
> in a xsl file. I have extracted a set of nodes that follow a XPath
> rule where an attribute is set, and am paaaing this a a parameter to
> a template.
>
> <xsl:with-param name="image-nodes">
>     <xsl:value-of select="xalan:nodeset(.)/image[@position = 'left']" />
> </xsl:with-param>

When you use the content of a variable-binding element
(<xsl:variable>, <xsl:param> or <xsl:with-param>), the result is a
result tree fragment -- a small tree that you can't further process.
If you want to set a variable/parameter to existing nodes (or to
simple values like numbers and strings) then you should use the select
attribute instead:

  <xsl:with-param name="image-nodes"
    select="xalan:nodeset(.)/image[@position = 'left']" />

By the way, I doubt that xalan:nodeset(.) is doing anything for you
here, since it's used to convert result tree fragments to node sets,
but the context node (.) cannot be a result tree fragment. I think
that just:

  <xsl:with-param name="image-nodes"
                  select="image[@position = 'left']" />

will do what you want.

A quick scan through your stylesheet shows that you're using the
content of the variable-binding elements quite a lot when you should
be using the select attribute instead.

By the way, the latest version of Xalan supports exsl:node-set(),
which will work with other processors as well, so for portability it's
better to use exsl:node-set() than xalan:nodeset().

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/


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