<grammar xmlns="http://relaxng.org/ns/structure/1.0">

  <define name="inline">

    <zeroOrMore>

      <ref name="inline.class"/>

    </zeroOrMore>

  </define>

  <define name="inline.class">

    <choice>

      <text/>

      <element name="bold">

	<ref name="inline"/>

      </element>

      <element name="italic">

	<ref name="inline"/>

      </element>

    </choice>

  </define>

</grammar>