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>