/*
 * call-seq:
 *  &(node_set)
 *
 * Set Intersection — Returns a new NodeSet containing nodes common to the two NodeSets.
 */
static VALUE intersection(VALUE self, VALUE rb_other)
{
  xmlNodeSetPtr node_set;
  xmlNodeSetPtr other;

  if(!rb_obj_is_kind_of(rb_other, cNokogiriXmlNodeSet))
    rb_raise(rb_eArgError, "node_set must be a Nokogiri::XML::NodeSet");

  Data_Get_Struct(self, xmlNodeSet, node_set);
  Data_Get_Struct(rb_other, xmlNodeSet, other);

  return Nokogiri_wrap_xml_node_set(xmlXPathIntersection(node_set, other), rb_iv_get(self, "@document"));
}