Recipe Subtypes

<xs:complexType name="FoodRecipe">
  <xs:complexContent>
    <xs:extension base="r:Recipe"/>
  </xs:complexContent>
</xs:complexType>

<xs:complexType name="CandyRecipe">
  <xs:complexContent>
    <xs:extension base="r:FoodRecipe">
      <xs:attribute name="sugarfree" type="xs:boolean"/>
    </xs:extension>
  </xs:complexContent>
</xs:complexType>

<xs:complexType name="DrinkRecipe">
  <xs:complexContent>
    <xs:extension base="r:Recipe">
      <xs:attribute name="virgin" type="xs:boolean"/>
    </xs:extension>
  </xs:complexContent>
</xs:complexType>