1<grammar xmlns="http://relaxng.org/ns/structure/1.0">
2  <start>
3    <ref name="inline"/>
4  </start>
5
6  <define name="inline">
7    <zeroOrMore>
8      <choice>
9        <text/>
10        <element name="code">
11          <ref name="inline"/>
12        </element>
13        <element name="em">
14          <ref name="inline"/>
15        </element>
16        <!-- etc -->
17      </choice>
18    </zeroOrMore>
19  </define>
20</grammar>
21