Wordpress walker call parent walk() method

Question

When extending the base Walker class I need to extend the walk() method.

However, calling the parent walk() method yields no results.

These are the approaches I have tried:

public function walk($elements, $max_depth) {
   parent::walk($elements, $max_depth);
}

public function walk($elements, $max_depth) {
   $parent_class=get_parent_class($this);
   $args = array($elements, $max_depth);

   call_user_func_array(array($parent_class, 'walk'), $args);
}

It appears to me that as soon as I override the walk() things break.

Should this method return some specific value? Should I call the parent method differently?

Answer 1

Walker::walk will return the string resulting from the walk operation. What you will get is a text that has been created using the methods Walker::display_element, Walker::start_lvl, Walker::start_el and so on... What you will get from the parent method is already HTML code probably hard to modify in the right way in a second time, but if you really want to do that:

public function walk($elements, $max_depth) {
  $html = parent::walk($elements, $max_depth);

  /* Do something with the HTML output */

  return $html;
}