element attribute
{
   (
      attribute ns { text }?,
      attribute datatypeLibrary { xsd:anyURI }?,
      attribute * - (rng:* | local:*) { text }*
   ),
   (
      attribute name { xsd:QName }
    | (
         ( element * - rng:* { ... }* )
       & (
            element name { ... }
          | element anyName { ... }
          | element nsName { ... }
          | element choice { ... }
         )
      )
   ),
   (
      ( element * - rng:* { ... }* )
    & (
         element element { ... }
       | element attribute { ... }
       | element group { ... }
       | element interleave { ... }
       | element choice { ... }
       | element optional { ... }
       | element zeroOrMore { ... }
       | element oneOrMore { ... }
       | element list { ... }
       | element mixed { ... }
       | element ref { ... }
       | element parentRef { ... }
       | element empty { ... }
       | element text { ... }
       | element value { ... }
       | element data { ... }
       | element notAllowed { ... }
       | element externalRef { ... }
       | element grammar { ... }
      )?
   )
}