XML-LANG
Self-description with Document Type Definition (DTD):
- Structural rules of the document’s markup
- External entities, internal entities, non-XML resource entities
Non-Minimization (All Markup is Explicit)
XML Processor - customizable info structures
- Most XML users will not know they are using a DTD!
- XML-aware software works with custom XML apps without help
Document Validity = Conforms to DTD
- Document well-formedness = structurally sound, but no DTD
- Required Markup Declaration (RMD) indicates need for DTD
- Well-formedness for delivery format, validity for authoring