Selecting nodes with XPath

• One could select these item elements by navigating the DOM tree for the RSS document in code now that is has been loaded, but there is a better way : passing the parser an XPath selection query asking for just the elements one is interested in.
• XPath is built on a "path"-type notation within doucments, that starts from the root node (in this case the rss element), and each element node (as opposed to attributes and other node types) adds a level to that path
• In order to select ALL the item elements, one can pass such an XPath expresion to the parser from ObjectPAL:

  var nl OleAuto
    endVar
  [...]  
  nl = oDoc^selectNodes ("/rss/channel/item")

• The results in nl are a DOM "NodeList", containing a collection of all the subtree root nodes matching the XPath expression.
• In this example, the path has been given in absolute form, but relative paths exist too: in that case, the element node from which selectNodes is applied defines the context in relation to which the path is defined.