Datatypes in modularization of XHTMNL in XHTML schema

Looking at the datatypes module I wonder why more use isn't made of 
schema simple types. For example, the Datetime type is declared as

   <!-- date and time information. ISO date format -->
   <xs:simpleType name="Datetime">
     <xs:restriction base="xs:normalizedString"/>
   </xs:simpleType>

Why not derive from xs:dateTime instead?

Almost all the types strike me as more restrictable than has actually 
been done. For example, URIs is:

   <!-- a space-separated list of Uniform Resource Identifiers, see [URI] -->
   <xs:simpleType name="URIs">
     <xs:list itemType="xs:string"/>
   </xs:simpleType>

Conceptually it feels like it should be

   <!-- a space-separated list of Uniform Resource Identifiers, see [URI] -->
   <xs:simpleType name="URIs">
     <xs:list itemType="xs:anyURI"/>
   </xs:simpleType>

Even the types that don't exactly match a schema primitive type could 
constrained by a pattern facet. I think a more strictly typed XHTML 
schema could be useful for both documentation and testing, even if 
browsers were unlikely to use it as part of their parsing and 
rendering process.
-- 

   Elliotte Rusty Harold
   elharo@metalab.unc.edu
   Processing XML with Java (Addison-Wesley, 2002)
   http://www.cafeconleche.org/books/xmljava
   http://www.amazon.com/exec/obidos/ISBN%3D0201771861/cafeaulaitA

Received on Saturday, 23 August 2003 11:15:35 UTC