Question

Let’s say I have some XSL transforming XML. Is it possible for the same XSL sheet to run a second sweep over the resultant XML? For example, let’s say my XSL turns

<xml>
    <animal><dog>Rex</dog></animal>
    <animal><dog>Henry</dog></animal>
    <animal><dog>Fido</dog></animal>
</xml>

into

<xml>
    <dog>Rex</dog>
    <dog>Henry</dog>
    <dog>Fido</dog>
</xml>

I don’t want to output that; rather, I then want to perform more XSL based on THAT, i.e. resultant, XML structure.

A practical example? I want to append to each dog node the number of proceeding dog siblings it has. So it would end up like:

<xml>
    <dog>Rex (2)</dog>
    <dog>Henry (1)</dog>
    <dog>Fido (0)</dog>
</xml>

This could not be done on the first sweep because in the beginning XML, the dog nodes were not siblings – they each lived inside an animal node.

[EDIT: I know this could be done by interrogating instead the index of the parent animal node, but that’s only for this contrived example; generally, I still need to know how to act on transformed XML – if it’s even possible]

I hope that makes some sort of sense. If there is a really easy way to do this, go easy on me, as I’m no XSL ninja…

Thanks in advance

Answer 1

You can use modes on templates to process nodes more than one time but with different transformations. So you could do e.g.

<xsl:variable name="result1">
  <xsl:apply-templates select="xml" mode="m1"/>
</xsl:variable>

<xsl:variable name="result2">
  <xsl:apply-templates select="$result1/xml" mode="m2"/>
</xsl:variable>

<xsl:template match="/">
  <xsl:copy-of select="$result2"/>
</xsl:template>

<!-- now put templates for the modes here -->

That above is fine only with XSLT 2.0 however, with XSLT 1.0 you have the drawback that a temporary result is a result tree fragment which you need to convert into a node-set first with an extension function like exsl:node-set so with XSLT 1.0 you need e.g.

<xsl:variable name="result1">
  <xsl:apply-templates select="xml" mode="m1"/>
</xsl:variable>

<xsl:variable name="result2">
  <xsl:apply-templates select="exsl:node-set($result1)/xml" mode="m2"/>
</xsl:variable>

<xsl:template match="/">
  <xsl:copy-of select="$result2"/>
</xsl:template>

<!-- now put templates for the modes here -->