<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="index.on.role">
<refmeta>
<refentrytitle>index.on.role</refentrytitle>
<refmiscinfo class="other" otherclass="datatype">boolean</refmiscinfo>
</refmeta>
<refnamediv>
<refname>index.on.role</refname>
<refpurpose>Select indexterms based on <tag class="attribute">role</tag> value</refpurpose>
</refnamediv>

<refsynopsisdiv>
<src:fragment xml:id="index.on.role.frag">
<xsl:param name="index.on.role" select="0"/>
</src:fragment>
</refsynopsisdiv>

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

<para>
If non-zero, 
then an <tag>index</tag> element that has a
<tag class="attribute">role</tag> attribute
value will contain only those <tag>indexterm</tag>
elements with a matching role value.
If an <tag>index</tag> has no <tag class="attribute">role</tag>
attribute or it is blank, then the index will contain
all <tag>indexterm</tag>s in the current scope.
</para>
<para>
If <literal>index.on.role</literal> is zero, then the
<tag class="attribute">role</tag> attribute has no effect
on selecting indexterms for an index.
</para>

<para>If you are using DocBook version 4.3 or later, you should
use the <tag class="attribute">type</tag> attribute instead of <tag class="attribute">role</tag>
on <tag>indexterm</tag> and <tag>index</tag>,
and set the <parameter>index.on.type</parameter> to a nonzero
value.
</para>

</refsection>
</refentry>