<rng:element name="leaf">
<rng:ref name="att.global.attributes"/>
<rng:optional>
<rng:attribute name="value">
<rng:ref name="data.pointer"/>
</rng:attribute>
</rng:optional>
<rng:optional>
<rng:attribute name="parent">
<rng:ref name="data.pointer"/>
</rng:attribute>
</rng:optional>
<rng:optional>
<rng:attribute name="follow">
<rng:ref name="data.pointer"/>
</rng:attribute>
</rng:optional>
<rng:optional>
<rng:ref name="label"/>
</rng:optional>
</rng:element>
element leaf
{
att.global.attributes,
attribute value { data.pointer }?,
attribute parent { data.pointer }?,
attribute follow { data.pointer }?,
label?
}