<?xml version="1.0" encoding="UTF-8"?>
<grammar ns="" xmlns="http://relaxng.org/ns/structure/1.0"
  datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
  <start>
    <element name="metadata">
      <attribute name="version">
        <data type="decimal"/>
      </attribute>
      <interleave>
        <optional>
          <element name="uniqueid">
            <attribute name="id"/>
          </element>
        </optional>
        <optional>
          <element name="vendor">
            <optional>
              <attribute name="name"/>
            </optional>
            <optional>
              <attribute name="url"/>
            </optional>
          </element>
        </optional>
        <optional>
          <element name="credits">
            <oneOrMore>
              <element name="credit">
                <attribute name="name"/>
                <attribute name="role"/>
               <optional>
                  <attribute name="url">
                    <data type="anyURI"/>
                  </attribute>
                </optional>
              </element>
            </oneOrMore>
          </element>
        </optional>
        <optional>
          <element name="description">
            <ref name="text"/>
          </element>
        </optional>
        <optional>
          <element name="license">
            <attribute name="id">
              <data type="NCName"/>
            </attribute>
            <attribute name="url">
              <data type="anyURI"/>
            </attribute>
            <oneOrMore>
              <ref name="text"/>
            </oneOrMore>
          </element>
        </optional>
        <optional>
          <element name="copyright">
            <oneOrMore>
              <ref name="text"/>
            </oneOrMore>
          </element>
        </optional>
        <optional>
          <element name="trademark">
            <oneOrMore>
              <ref name="text"/>
            </oneOrMore>
          </element>
        </optional>
        <optional>
          <element name="licensee">
            <attribute name="name"/>
          </element>
        </optional>
        <optional>
          <element name="extension">
            <attribute name="id">
              <data type="NCName"/>
            </attribute>

              <zeroOrMore><ref name="name"/></zeroOrMore>
            <oneOrMore>
              <element name="item">
                <optional>
                  <attribute name="id"/>
                </optional>
                <oneOrMore>
                  <ref name="name"/>
                </oneOrMore>
                <oneOrMore>
                  <element name="value">
                    <optional>
                      <attribute name="lang">
                        <data type="NCName"/>
                      </attribute>
                    </optional>
                    <text/>
                  </element>
                </oneOrMore>
              </element>
            </oneOrMore>
          </element>
        </optional>
      </interleave>
    </element>
  </start>
  <define name="text">
    <element name="text">
      <optional>
        <attribute name="lang">
          <data type="NCName"/>
        </attribute>
      </optional>
      <text/>
    </element>
  </define>
  <define name="name">
    <element name="name">
      <optional>
        <attribute name="lang">
          <data type="NCName"/>
        </attribute>
      </optional>
      <text/>
    </element>
  </define>
</grammar>
