Doing a double-pass in XSL?

Question

Is it possible to store the output of an XSL transformation in some sort of variable and then perform an additional transformation on the variable\'s contents? (All in one X

Answer 1

Yes, with XSLT 2.0 it is easy. With XSLT 1.0 you can of course also use modes and store a temporary result in a variable the same way as in XSLT 2.0 but the variable is then a result tree fragment, to be able to process it further with apply-templates you need to use an extension function like exsl:node-set on the variable.

Answer 2

XSLT 2.0 Solution :

<xsl:variable name="firstPassResult">
  <xsl:apply-templates select="/" mode="firstPass"/>
</xsl:variable>

<xsl:template match="/">
  <xsl:apply-templates select="$firstPassResult" mode="secondPass"/>
</xsl:template>

The trick here, is to use mode="firstPassResult" for the first pass while all the templates for the sedond pass should have mode="secondPass".

Edit:

Example :

<root>
  <a>Init</a>
</root>

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output indent="yes"/>
  <xsl:strip-space elements="*"/>

  <xsl:variable name="firstPassResult">
    <xsl:apply-templates select="/" mode="firstPass"/>
  </xsl:variable>

  <xsl:template match="/" mode="firstPass">
      <test>
        <firstPass>
          <xsl:value-of select="root/a"/>
        </firstPass>
      </test>
  </xsl:template>

  <xsl:template match="/">
    <xsl:apply-templates select="$firstPassResult" mode="secondPass"/>
  </xsl:template>

  <xsl:template match="/" mode="secondPass">
    <xsl:message terminate="no">
      <xsl:copy-of select="."/>
    </xsl:message>
  </xsl:template>

</xsl:stylesheet>

Output :

[xslt] <test><firstPass>Init</firstPass></test>

So the first pass creates some elements with the content of root/a and the second one prints the created elements to std out. Hopefully this is enough to get you going.