gentoo-overlay/metadata/xml-schema/projects.xsd

<?xml version='1.0' encoding='UTF-8'?>

<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'>
	<xs:element name='projects'>
		<xs:complexType>
			<xs:choice minOccurs='0' maxOccurs='unbounded'>
				<xs:element name='project' type='projectType'>
					<xs:unique name='descUniquityConstraint'>
						<xs:selector xpath='description'/>
						<xs:field xpath='@fake-only-once'/>
					</xs:unique>
				</xs:element>
			</xs:choice>
		</xs:complexType>
		<xs:key name='projectKey'>
			<xs:selector xpath='project'/>
			<xs:field xpath='email'/>
		</xs:key>
		<xs:keyref name='subprojectRef' refer='projectKey'>
			<xs:selector xpath='project/subproject'/>
			<xs:field xpath='@ref'/>
		</xs:keyref>
		<!-- define additional keys to enforce exactly one element
			 of each kind -->
		<xs:key name='projectNameKey'>
			<xs:selector xpath='project'/>
			<xs:field xpath='name'/>
		</xs:key>
		<xs:key name='projectURLKey'>
			<xs:selector xpath='project'/>
			<xs:field xpath='url'/>
		</xs:key>
	</xs:element>

	<xs:complexType name='projectType'>
		<xs:choice minOccurs='0' maxOccurs='unbounded'>
			<xs:element name='email' type='emailType'/>
			<xs:element name='name' type='xs:token'/>
			<xs:element name='url' type='urlType'/>
			<xs:element name='description' type='descriptionType'/>
			<xs:element name='subproject' type='subprojectType'/>
			<xs:element name='member' type='memberType'/>
		</xs:choice>
	</xs:complexType>

	<xs:complexType name='descriptionType'>
		<xs:simpleContent>
			<xs:extension base='xs:token'>
				<xs:attribute name='fake-only-once'
					fixed='there can be at most one &lt;description/&gt; element'/>
			</xs:extension>
		</xs:simpleContent>
	</xs:complexType>

	<xs:complexType name='subprojectType'>
		<xs:attribute name='inherit-members' type='numericBoolType'/>
		<xs:attribute name='ref' type='projectRefType'/>
	</xs:complexType>

	<xs:simpleType name='projectRefType'>
		<xs:restriction base='emailType'>
		</xs:restriction>
	</xs:simpleType>

	<xs:complexType name='memberType'>
		<xs:all>
			<xs:element name='email' type='emailType'
				minOccurs='1' maxOccurs='1'/>
			<xs:element name='name' type='xs:token'
				minOccurs='0' maxOccurs='1'/>
			<xs:element name='role' type='xs:token'
				minOccurs='0' maxOccurs='1'/>
		</xs:all>
		<xs:attribute name='is-lead' type='numericBoolType'/>
	</xs:complexType>

	<!-- generic types -->
	<xs:simpleType name='emailType'>
		<xs:restriction base='xs:token'>
			<!-- minimal safe regex -->
			<xs:pattern value="[^@]+@[^.]+\..+"/>
		</xs:restriction>
	</xs:simpleType>

	<xs:simpleType name='urlType'>
		<xs:restriction base='xs:token'>
			<!-- TODO: something better? -->
			<xs:pattern value="https?://\S+"/>
		</xs:restriction>
	</xs:simpleType>

	<xs:simpleType name='numericBoolType'>
		<xs:restriction base='xs:integer'>
			<xs:minInclusive value='0'/>
			<xs:maxInclusive value='1'/>
		</xs:restriction>
	</xs:simpleType>
</xs:schema>