code: public function raw(/*# string */ $string)/*# : RawInterface */
      {
          // get values from argument list
          if (func_num_args() > 1) {
              $values = func_get_args();
              array_shift($values);
  
              // replacement
              $pat = $rep = [];
              foreach ($values as $val) {
                  $pat[] = '/\?/';
                  $rep[] = $this->generatePlaceholder($val);
              }
  
              return new Raw(preg_replace($pat, $rep, $string, 1), $this);
          } else {
              return new Raw($string, $this);
          }
      }
docs: {@inheritDoc}