<refentry id="index.on.role">
<refmeta>
<refentrytitle>index.on.role</refentrytitle>
<refmiscinfo role="type">boolean</refmiscinfo>
</refmeta>
<refnamediv>
<refname>index.on.role</refname>
<refpurpose>Select indexterms based on role value</refpurpose>
</refnamediv>

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

<refsect1><title>Description</title>

<para>
If non-zero, 
then an <sgmltag>index</sgmltag> element that has a
<sgmltag>role</sgmltag> attribute
value will contain only those <sgmltag>indexterm</sgmltag>
elements with a matching role value.
If an <sgmltag>index</sgmltag> has no <sgmltag>role</sgmltag>
attribute or it is blank, then the index will contain
all <sgmltag>indexterm</sgmltag>s in the current scope.
</para>
<para>
If <literal>index.on.role</literal> is zero, then the
<sgmltag>role</sgmltag> 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 <sgmltag>type</sgmltag> attribute instead of <sgmltag>role</sgmltag>
on <sgmltag>indexterm</sgmltag> and <sgmltag>index</sgmltag>,
and set the <parameter>index.on.type</parameter> to a nonzero
value.
</para>

</refsect1>
</refentry>
