/*
 * call-seq:
 *   depth
 *
 * Get the depth of the node
 */
static VALUE depth(VALUE self)
{
  xmlTextReaderPtr reader;
  int depth;

  Data_Get_Struct(self, xmlTextReader, reader);
  depth = xmlTextReaderDepth(reader);
  if(depth == -1) return Qnil;

  return INT2NUM((long)depth);
}