Class LibXML::XML::XPath::Context
In: ext/libxml/ruby_xml_xpath.c
Parent: Object

The XML::XPath::Context class is used to evaluate XPath expressions. Generally, you should not directly use this class, but instead use the XML::Document#find and XML::Node#find methods. 

 doc = XML::Document.string('<header>content</header>')
 context = XPath::Context.new(doc)
 context.node = doc.root
 context.register_namespaces_from_node(doc.root)
 nodes = context.find('/header')

Methods

find   new   node=   register_namespace   register_namespaces   register_namespaces_from_node  

Attributes

doc  [R] 

Public Class methods

XPath::Context.new(node) → XPath::Context

Creates a new XPath context for the specified document. The context can then be used to evaluate an XPath expression. 

 doc = XML::Document.string('<header><first>hi</first></header>')
 context = XPath::Context.new(doc)
 nodes = XPath::Object.new('//first', context)
 nodes.length == 1

[Source]

/* call-seq:
 *    XPath::Context.new(node) -> XPath::Context
 * 
 * Creates a new XPath context for the specified document.  The
 * context can then be used to evaluate an XPath expression.
 *
 *  doc = XML::Document.string('<header><first>hi</first></header>')
 *  context = XPath::Context.new(doc)
 *  nodes = XPath::Object.new('//first', context)
 *  nodes.length == 1
 */
VALUE
ruby_xml_xpath_context_initialize(VALUE self, VALUE node) {

Public Instance methods

context.find("xpath") → XML::XPath::Object

Find nodes matching the specified XPath expression

[Source]

/*
 * call-seq:
 *    context.find("xpath") -> XML::XPath::Object
 * 
 * Find nodes matching the specified XPath expression
 */
VALUE
ruby_xml_xpath_context_find(VALUE self, VALUE xpath_expr) {
context.node = node

Set the current node used by the XPath engine 

 doc = XML::Document.string('<header><first>hi</first></header>')
 context.node = doc.root.first

[Source]

/*
 * call-seq:
 *    context.node = node
 * 
 * Set the current node used by the XPath engine
 
 *  doc = XML::Document.string('<header><first>hi</first></header>')
 *  context.node = doc.root.first
 */
VALUE
ruby_xml_xpath_context_node_set(VALUE self, VALUE node) {
context.register_namespace(prefix, uri) → (true|false)

Register the specified namespace URI with the specified prefix in this context. 

  context.register_namespace('xi', 'http://www.w3.org/2001/XInclude')

[Source]

/*
 * call-seq:
 *    context.register_namespace(prefix, uri) -> (true|false)
 * 
 * Register the specified namespace URI with the specified prefix
 * in this context.
 
 *   context.register_namespace('xi', 'http://www.w3.org/2001/XInclude')
 */
VALUE
ruby_xml_xpath_context_register_namespace(VALUE self, VALUE prefix, VALUE uri) {
context.register_namespaces(["prefix:uri"]) → self

Register the specified namespaces in this context. 

  context.register_namespaces('xi:http://www.w3.org/2001/XInclude')
  context.register_namespaces(['xlink:http://www.w3.org/1999/xlink',
                               'xi:http://www.w3.org/2001/XInclude')
  context.register_namespaces('xlink' => 'http://www.w3.org/1999/xlink',
                                 'xi' => 'http://www.w3.org/2001/XInclude')

[Source]

/*
 * call-seq:
 *    context.register_namespaces(["prefix:uri"]) -> self
 * 
 * Register the specified namespaces in this context.
 *
 *   context.register_namespaces('xi:http://www.w3.org/2001/XInclude')
 *   context.register_namespaces(['xlink:http://www.w3.org/1999/xlink',
 *                                'xi:http://www.w3.org/2001/XInclude')
 *   context.register_namespaces('xlink' => 'http://www.w3.org/1999/xlink',
 *                                  'xi' => 'http://www.w3.org/2001/XInclude')
 */
VALUE
ruby_xml_xpath_context_register_namespaces(VALUE self, VALUE nslist) {
context.register_namespaces_from_node(node) → self

Helper method to read in namespaces defined on a node. 

 doc = XML::Document.string('<header><first>hi</first></header>')
 context = XPath::Context.new(doc)
 context.register_namespaces_from_node(doc.root)

[Source]

/* call-seq:
 *    context.register_namespaces_from_node(node) -> self
 * 
 * Helper method to read in namespaces defined on a node.
 *
 *  doc = XML::Document.string('<header><first>hi</first></header>')
 *  context = XPath::Context.new(doc)
 *  context.register_namespaces_from_node(doc.root)
 */
VALUE
ruby_xml_xpath_context_register_namespaces_from_node(VALUE self, VALUE node) {

[Validate]