Re: [xsl] recursivly applying a transform to a result tree

[tcn at melvaig dot co dot uk (Trevor Nash)]

>The language is completly recursive by nature and obviously so is an
>implementation of the transform.
>But something strikes me as being very odd. Why are there no facilities for
>recursivly applying a transform to a result tree fragment ? Is this a design
>philosophy or perhaps a omission cq flaw ?

Is this the sort of thing you have in mind:

given <a depth="n"/> the following transform yields an <a> element
with n nested <x> elements, e.g. 

    <a depth=3/>

gives

    <a><x><x><x/></x></x></a>

(its not supposed to be useful, just to demonstrate).

This works with processors which support XSLT1.1, for example with
Saxon 6.2.2.  NB, XSLT 1.1 is not a recommendation yet.  For other
processors you may be able to use the extension function node-set().

<xsl:stylesheet
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; version="1.0"
>

<xsl:template match="a[@depth=0]">
   <a><xsl:copy-of select="child::node()"/></a>
</xsl:template>

<xsl:template match="a[@depth>0]">
   <xsl:variable name="tree">
      <a depth="{@depth - 1}">
          <x><xsl:copy-of select="node()"/></x>
      </a>
   </xsl:variable>
   <xsl:apply-templates select="$tree"/>
</xsl:template>

</xsl:stylesheet>

Is this of any help?

Regards,
Trevor Nash

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