<element name=“example” xmlns=“relaxng.org/ns/structure/1.0”>

<zeroOrMore>
  <attribute>
    <anyName>
      <except>
        <name>xml:space</name>
      </except>
    </anyName>
  </attribute>
</zeroOrMore>
<optional>
  <attribute name="xml:space">
    <choice>
      <value>default</value>
      <value>preserve</value>
    </choice>
  </attribute>
</optional>

</element>