Extract the definition to a new type to allow avoiding of duplication.
</attribute>
</optional>
<interleave>
- <optional>
- <element name='driver'>
- <optional>
- <attribute name='type'>
- <ref name='storageFormat'/>
- </attribute>
- </optional>
- <empty/>
- </element>
- </optional>
+ <ref name='disksnapshotdriver'/>
<optional>
<element name='source'>
<optional>
</element>
</define>
+ <define name='disksnapshotdriver'>
+ <optional>
+ <element name='driver'>
+ <optional>
+ <attribute name='type'>
+ <ref name='storageFormat'/>
+ </attribute>
+ </optional>
+ <empty/>
+ </element>
+ </optional>
+ </define>
+
</grammar>