PIDF - using xml schema

I know there was discussion of using XML Schema back in December, but some
of that was more about whether validation needed to be done.  If the format
is XML it should be possible to also define it using XML Schema - and more
precisely - especially for showing where the extensions can go and also
types.

Here's a very quickly written version I made - I'm new to reading the list
mail and drafts.  I think something like this in an appendix would help
people get a clearer idea of the format than just the DTD since it makes
both the extensions and types clear.  I think it's easier to read a simple
schema than a DTD too.

----------- XML Schema follows -------------

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified" attributeFormDefault="unqualified">

	<xs:element name="presence" type="presence" />

	<xs:complexType name="presence">
		<xs:sequence>
			<xs:element name="tuple" type="tuple"
maxOccurs="unbounded" />
			<xs:element name="note" type="xs:string"
minOccurs="0" />
			<xs:any namespace="##other" minOccurs="0"
maxOccurs="unbounded" processContents="lax" />
		</xs:sequence>
		<xs:attribute name="entity" type="xs:anyURI" use="required"
/>
	</xs:complexType>
	
	<xs:complexType name="tuple">
		<xs:sequence>
			<xs:element name= "status" type="status" />
			<xs:element name="contact" type="contact"
minOccurs="0" />
			<xs:element name="note" type="xs:string"
minOccurs="0" />
			<xs:element name="timestamp" type="xs:dateTime"
minOccurs="0"  />
		</xs:sequence>
		<xs:attribute name="id" type="xs:ID" use="required" />
	</xs:complexType>
	
	<xs:complexType name="status">
		<xs:sequence>
			<xs:element name= "basic" type="basic" />
			<xs:any namespace="##other" minOccurs="0"
maxOccurs="unbounded" processContents="lax" />
		</xs:sequence>
	</xs:complexType>	
	
	<xs:simpleType name="basic">
		<xs:restriction base="xs:string">
    			<xs:enumeration value="open"/>
    			<xs:enumeration value="closed"/>
    		</xs:restriction>
    	</xs:simpleType>
    	
    	<xs:complexType name="contact">
		<xs:simpleContent>
    			<xs:extension base="xs:anyURI">
				<xs:attribute name="priority"
type="xs:unsignedByte" />
			</xs:extension>
		</xs:simpleContent>
	</xs:complexType>
 
 <!-- Global Attributes -->
 <xs:attribute name="mustUnderstand" type="xs:boolean" default="0" />
	
</xs:schema>





  [reminder: [email protected] for non-technical discussions, please]