Processing topics with XSLT in preprocess

You can add an Ant target to the end of the pre-processing pipeline that transforms all topics. This is useful if you want to modify topics before transtype-specific processing, for example to modularize the code or reuse the same processing in multiple transformation types.

Create a plug-in descriptor file plugin.xml that imports a new Ant buildfile build.xml and adds an Ant target after pre-processing.

<?xml version="1.0" encoding="utf-8"?>
<?xml-model href="https://www.dita-ot.org/rng/plugin.rnc" type="application/relax-ng-compact-syntax"?>
<plugin id="plugin-id">
  <feature extension="ant.import" file="build.xml"/>
  <feature extension="depend.preprocess.post" value="uniform-decimals"/>
</plugin>

Create an Ant buildfile build.xml with a target to process all DITA topics in the temporary directory.

<?xml version="1.0" encoding="utf-8"?>
<project>
  <target name="uniform-decimals">
    <pipeline taskname="xslt">
      <xslt basedir="${dita.temp.dir}"
            style="${dita.plugin.plugin-id.dir}/filter.xsl">
        <ditafileset format="dita" processingRole="normal"/>
      </xslt>
    </pipeline>
  </target>
</project>

Create an XSLT stylesheet filter.xsl to filter topic content.

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xs">

  <!-- Format keywords with a decimal number with at least two decimal points -->
  <xsl:template match="*[contains(@class, ' topic/keyword ')]">
    <xsl:copy>
      <xsl:apply-templates select="@*"/>
      <xsl:variable name="num" select="number(.)" as="xs:double"/>
      <xsl:choose>
        <xsl:when test="$num = $num and contains(., '.')">
          <xsl:attribute name="orig" select="."/>
          <xsl:value-of select="format-number($num, '0.00#')"/>
        </xsl:when>
        <xsl:otherwise>
          <xsl:apply-templates select="node()"/>
        </xsl:otherwise>
      </xsl:choose>
    </xsl:copy>
  </xsl:template>

  <!-- Identity template -->
  <xsl:template match="@* | node()">
    <xsl:copy>
      <xsl:apply-templates select="@* | node()"/>
    </xsl:copy>
  </xsl:template>

</xsl:stylesheet>

Use the dita install subcommand to install the plug-in.

Note:
For more information, see Installing plug-ins.

The filter.xsl stylesheet will transform every DITA topic after pre-processing.