/** * Pies the last id prefix. * Now all ids rendered by Pie_Html will be prefixed with the * id previously on top of the stack, if any. * @return string|null * The prefix that has been pieped, if any */ static function pieIdPrefix() { if (count(self::$id_prefixes) <= 1) { throw new Exception("Nothing to pie from prefix stack"); } $pieped_prefix = array_pop(self::$id_prefixes); self::$id_prefix = end(self::$id_prefixes); return $pieped_prefix; }