XLink, XPointer, and XPath

Three layers:

• XLink
  • a generalization of the HTML link concept
  • higher abstraction level (intended for general XML - not just hypertext)
  • more expressive power (multiple destinations, special behaviours, out-of-line links, ...)
  • uses XPointer to locate resources
• XPointer
  • an extension of XPath suited for linking
  • specifies connection between XPath expressions and URIs
• XPath
  • a declarative language for locating nodes and fragments in XML trees
  • used in both XPointer (for addressing) and XSL (for pattern matching)