Is there a way to perform syntax colouring using Ditac (the DITA converter by XML Mind)? Any XSLT1 or XSLT2 based solution would work provided that it supports both XHTML and XSL:FO output.
XSLTHL (http://sourceforge.net/projects/xslthl/) has been suggested, though Saxon-HE (used by Ditac) doesn't seem to detect the extension JAR file.
I modified the provided XSL files so that they should work with DITA; but the default behaviour of just copying the non-coloured source listing occurs because the extension function is not being detected:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:fo="http://www.w3.org/1999/XSL/Format"
xmlns:ditac="http://www.xmlmind.com/ditac/schema/ditac"
xmlns:u="http://www.xmlmind.com/namespace/ditac"
version="2.0">
<xsl:import href="ditac-xsl:fo/fo.xsl"/>
<xsl:import href="highlighting/fo.xsl"/>
<!-- Syntax highlighting -->
<xsl:template match="*[contains(@class,' topic/pre ')]">
<fo:block xsl:use-attribute-sets="pre">
<xsl:call-template name="commonAttributes"/>
<xsl:call-template name="displayAttributes"/>
<xsl:call-template name="apply-highlighting"/>
</fo:block>
</xsl:template>
...
"highlighting/fo.xsl" includes another file called "highlighting/common.xsl" (I took and modified these files from Docbook). Here is the part that should link with Saxon:
<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:sbhl="http://net.sf.xslthl/ConnectorSaxonB"
xmlns:saxonb="http://saxon.sf.net/"
xmlns:exsl="http://exslt.org/common"
xmlns:xslthl="http://xslthl.sf.net"
exclude-result-prefixes="exsl xslthl sbhl"
version='1.0'>
<!-- ********************************************************************
$Id: common.xsl,v 1.11 2009/06/02 11:41:23 sorin Exp $
********************************************************************
This file is part of the XSL DocBook Stylesheet distribution.
See ../README or http://docbook.sf.net/release/xsl/current/ for
and other information.
******************************************************************** -->
<!-- for saxon 8.5 and later -->
<saxonb:script implements-prefix="sbhl" language="java" src="java:net.sf.xslthl.ConnectorSaxonB" />
<xsl:variable name="highlight.default.language" select="csharp"/>
<!-- You can override this template to do more complex mapping of
language attribute to highlighter language ID (see xslthl-config.xml) -->
<xsl:template name="language.to.xslthl">
<xsl:param name="context"/>
<xsl:choose>
<xsl:when test="$context/@outputclass != ''">
<xsl:value-of select="$context/@outputclass"/>
</xsl:when>
<xsl:when test="$highlight.default.language != ''">
<xsl:value-of select="$highlight.default.language"/>
</xsl:when>
</xsl:choose>
</xsl:template>
<xsl:template name="apply-highlighting">
<xsl:variable name="language">
<xsl:call-template name="language.to.xslthl">
<xsl:with-param name="context" select="."/>
</xsl:call-template>
</xsl:variable>
<xsl:choose>
<xsl:when test="$language != ''">
<xsl:variable name="content">
<xsl:apply-templates/>
</xsl:variable>
<xsl:choose>
<xsl:when test="function-available('sbhl:highlight')">
<xsl:apply-templates select="sbhl:highlight($language, exsl:node-set($content), 'xslthl-config.xml')" mode="xslthl"/>
</xsl:when>
<xsl:otherwise>
<xsl:copy-of select="$content"/>
</xsl:otherwise>
</xsl:choose>
</xsl:when>
<xsl:otherwise>
<xsl:apply-templates/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<!-- A fallback when the specific style isn't recognized -->
<xsl:template match="xslthl:*" mode="xslthl">
<xsl:message>
<xsl:text>unprocessed xslthl style: </xsl:text>
<xsl:value-of select="local-name(.)" />
</xsl:message>
<xsl:apply-templates mode="xslthl"/>
</xsl:template>
<!-- Copy over already produced markup (FO/HTML) -->
<xsl:template match="node()" mode="xslthl" priority="-1">
<xsl:copy>
<xsl:apply-templates select="node()" mode="xslthl"/>
</xsl:copy>
</xsl:template>
<xsl:template match="*" mode="xslthl">
<xsl:copy>
<xsl:copy-of select="@*"/>
<xsl:apply-templates select="node()" mode="xslthl"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>