Add a class at specific element in custom Menu Walker

Question

I have customised my menu in wordpress by extending the Nav_Menu_Walker class and now i cannot figure it out how could i add a class at a specific ul element. I have this function which adds classes by depth:

function start_lvl(&$output, $depth) {
 $indent = str_repeat("\t", $depth);
 if ($depth >= 1)
    $output .= "\n$indent<ul class=\"subsubmenu\">\n";
 else
    $output .= "\n$indent<ul class=\"submenu\">\n";

}

When the $depth is 0 i would like to add a different class at the third element from $depth =0 rather than "submenu".

Could you please provide me some suggestions ?

Answer 1

Count the level 0 elements in a static variable in the method and add an extra class if you hit the third. Sample code, not tested:

function start_lvl(&$output, $depth) {
    static $column = 1;
    $indent = str_repeat("\t", $depth);
    if ($depth > 0)
    {
        $output .= "\n$indent<ul class='subsubmenu'>\n";
    }
    else
    {
        $column += 1;
        $extra = 3 === $column ? ' third-column' : '';
        $output .= "\n$indent<ul class='submenu$extra'>\n";
    }
}