<xs:simpleType name="accidental-text">
  <xs:annotation>
    <xs:documentation>Notated accidentals supported by MusicXML. In the MusicXML 2.0 DTD this was a string with values that could be included. Here we strengthen the data typing to an enumerated list.</xs:documentation>
  </xs:annotation>
  <xs:restriction base="xs:string">
    <xs:enumeration value="sharp"/>
    <xs:enumeration value="natural"/>
    <xs:enumeration value="flat"/>
    <xs:enumeration value="double-sharp"/>
    <xs:enumeration value="sharp-sharp"/>
    <xs:enumeration value="flat-flat"/>
    <xs:enumeration value="natural-sharp"/>
    <xs:enumeration value="natural-flat"/>
    <xs:enumeration value="quarter-flat"/>
    <xs:enumeration value="quarter-sharp"/>
    <xs:enumeration value="three-quarters-flat"/>
    <xs:enumeration value="three-quarters-sharp"/>
  </xs:restriction>
</xs:simpleType>