public function format_template($field)
    {
        if (!($t = $this->columns[$field]['template'])) {
            throw new BaseException('use setTemplate() for field '.$field);
        }

        $this->current_row_html[$field] = $t
            ->trySet('id', $this->current_id)
            ->set($this->current_row)
            ->trySet('_value_', $this->current_row[$field])
            ->render();
    }