slide 4

XPath Has Two Main Uses

• First use: Locating nodes in a tree
  • Locating elements in an XML document
  • A way of asking the computer for something in an XML document (“gimme my message number!”)
    ... and getting it back
• Second use: performing operations over data
  • Numeric operations: counting, adding, rounding etc.
  • String operations: substrings, substitutions ...
  • Boolean (for conditionals); equality operations, comparisons between numbers or nodes ...
• The emphasis of XPath has shifted in 2.0
  ... the second application is now foregrounded
  • (In this XPath 2.0 shows its kinship to XQuery)