public function templateSettings($settings=null) {
    $_template_settings =& self::getInstance()->_template_settings;
    
    if(is_null($settings)) {
      $_template_settings = array(
        'evaluate'    => self::TEMPLATE_DEFAULT_EVALUATE,
        'interpolate' => self::TEMPLATE_DEFAULT_INTERPOLATE,
        'escape'      => self::TEMPLATE_DEFAULT_ESCAPE
      );
      return true;
    }
    
    foreach($settings as $k=>$v) {
      if(!array_key_exists($k, $_template_settings)) continue;
      
      $_template_settings[$k] = $v;
    }
    return true;
  }