P5: Linee guida per la codifica e l'interscambio del testo elettronico

<rng:element name="tech">
<rng:ref name="att.global.attributes"/>
<rng:optional>
 <rng:attribute name="type">
  <rng:choice>
   <rng:value>light</rng:value>
   <rng:value>sound</rng:value>
   <rng:value>prop</rng:value>
   <rng:value>block</rng:value>
  </rng:choice>
 </rng:attribute>
</rng:optional>
<rng:optional>
 <rng:attribute name="perf">
  <rng:ref name="data.enumerated"/>
 </rng:attribute>
</rng:optional>
<rng:ref name="macro.paraContent"/>
</rng:element>

element tech
{
   att.global.attributes,
   attribute type { "light" | "sound" | "prop" | "block" }?,
   attribute perf { data.enumerated }?,
   macro.paraContent
}