Members of the W3C XML Schema Working Group now invite implementationof the Candidate Recommendation specification "W3C XML Schema DefinitionLanguage (XSD): Component Designators." The Candidate Recommendationreview period for this document extends until 1-March-2010. Comments onthis document should be made in W3C's public installation of Bugzilla,specifying 'XML Schema' as the product.
A test suite is under development that identifies the set of canonicalschema component paths that should be generated for particular testschemas, and that relates certain non-canonical component paths to thecorresponding canonical schema component paths. The W3C XML SchemaWorking Group has agreed on the following specific CR exit criteria:(1) A test suite is available which provides cases for each axis andcomponent type, both for the XML Schema 1.0 component model and the XMLSchema 1.1 component model. (2) Generation or interpretation of canonicalschema component paths have been implemented successfully by at leasttwo independent implementations. (3) Generation or interpretation ofeach axis and component for non-canonical schema component paths hasbeen implemented successfully by at least two independent implementations.(4) The Working Group has responded formally to all issues raisedagainst this document during the Candidate Recommendation period.
"XML Schema: Component Designators" defines a scheme for identifying XMLSchema components as specified by 'XML Schema Part 1: Structures' and'XML Schema Part 2: Datatypes'. Part 1 of the W3C XML Schema DefinitionLanguage (XSD) recommendation defines these schema components, whereSection 2.2 lays out the inventory of schema components into three classes:(a) Primary components: simple and complex type definitions, attributedeclarations, and element declarations (b) Secondary components: attributeand model group definitions, identity-constraint definitions, and notationdeclarations (c) "Helper" components: annotations, model groups, particles,wildcards, and attribute uses In addition there is a master schemacomponent, the schema component representing the schema as a whole..."
http://www.w3.org/TR/2010/CR-xmlschema-ref-20100119/See also the W3C XML Schema Working Group: http://www.w3.org/XML/Schema