function indenter($locations, $parent_id = null, $prefix = '') {
    $results = Array();
    foreach($locations as $location) {
        if($location->parent_id == $parent_id) {
            //append this parent node first,
            $location->use_text = $prefix.' '.$location->name
            $results[] = $location;
            //now append the children.
            $results = array_merge($results,indenter($locations,$location->id,$prefix.'--'));
        }
    }
    return $results;
}