<grammar xmlns="http://relaxng.org/ns/structure/1.0"> <include href="inline2.rng"/> <start> <element name="doc"> <zeroOrMore> <element name="p"> <ref name="inline"/> </element> </zeroOrMore> </element> </start> <define name="inline.class" combine="choice"> <choice> <element name="code"> <ref name="inline"/> </element> <element name="em"> <ref name="inline"/> </element> </choice> </define> </grammar>