lfs-book/stylesheets/lfs-xsl/docbook-xsl-1.78.1/params/refentry.source.fallback.profile.xml

<refentry xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xi="http://www.w3.org/2001/XInclude"
          xmlns:src="http://nwalsh.com/xmlns/litprog/fragment"
          xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
          version="5.0" xml:id="refentry.source.fallback.profile">
<refmeta>
<refentrytitle>refentry.source.fallback.profile</refentrytitle>
<refmiscinfo class="other" otherclass="datatype">string</refmiscinfo>
</refmeta>
<refnamediv>
<refname>refentry.source.fallback.profile</refname>
<refpurpose>Specifies profile of "fallback" for refentry "source" data</refpurpose>
</refnamediv>

<refsynopsisdiv>
<src:fragment xml:id="refentry.source.fallback.profile.frag">
<xsl:param name="refentry.source.fallback.profile">
refmeta/refmiscinfo[not(@class = 'date')][1]/node()</xsl:param>
</src:fragment>
</refsynopsisdiv>

<refsection><info><title>Description</title></info>

<para>The value of
<parameter>refentry.source.fallback.profile</parameter> is a string
representing an XPath expression. It is evaluated at run-time and used
only if no "source" data can be found by other means (that is, either
using the <tag>refentry</tag> metadata-gathering logic "hard coded" in
the stylesheets, or the value of the
<parameter>refentry.source.name.profile</parameter> and
<parameter>refentry.version.profile</parameter> parameters, if those
are enabled).</para>

<important>
<para>Depending on which XSLT engine you run, either the EXSLT
<function>dyn:evaluate</function> extension function (for xsltproc or
Xalan) or <function>saxon:evaluate</function> extension function (for
Saxon) are used to dynamically evaluate the value of
<parameter>refentry.source.fallback.profile</parameter> at
run-time. If you don't use xsltproc, Saxon, Xalan -- or some other
XSLT engine that supports <function>dyn:evaluate</function> -- you
must manually disable fallback processing by setting an empty value
for the <parameter>refentry.source.fallback.profile</parameter>
parameter.</para>
</important>

</refsection>
</refentry>