XML News from Sunday, July 18, 2004

The W3C XML Schema Working Group has published an updated working draft of XML Schema: Component Designators. This spec proposes a scheme for naming and identifying XML Schema components. Such components include:

• Simple and complex type definitions
• Attribute declarations
• Element declarations
• Attribute and model group definitions
• Identity-constraint definitions
• Notation declarations
• Annotations
• Model groups
• Particles
• Wildcards
• Attribute uses
• The master schema component representing the schema as a whole.
• Facets

The goal is to be able to name, for example, the literallayout notation in the DocBook schema, as well as every other significant piece of the schema. These names could then be used as fragment identifiers in URI references that point to schemas. The draft gives these examples of the current syntax proposal:

schema-URI#xscd(/type(Items))
schema-URI#xscd(/type(Items)/item)
schema-URI#xscd(/type(Items)/item/type())
schema-URI#xscd(/type(Items)/item/productName)
schema-URI#xscd(/type(Items)/item/quantity)
schema-URI#xscd(/type(Items)/item/quantity/type())
schema-URI#xscd(/type(Items)/item/quantity/type()/facet(maxExclusive))
schema-URI#xscd(/type(Items)/item/USPrice)
schema-URI#xscd(/comment)
schema-URI#xscd(/type(Items)/item/shipDate)
schema-URI#xscd(/type(Items)/item/@partNum)