private function printParameters($name, $def, $length)
    {
        $name .= str_repeat(' ', 2 + $length - strlen($name));
        $this->stdio->write($name, false, [Stdio::STYLE_GREEN]);

        $this->stdio->write(trim($def['description'] ?: ''));

        if (array_key_exists('default', $def)) {
            $default = $def['default'];
            if ($default === null) {
                $default = 'null';
            }
            else if ($def['type'] == 'string') {
                $default = '"' . $default . '"';
            }
            $this->stdio->write(' [default: ' . $default . ']', true);
        }
        else {
            $this->stdio->write('', true);
        }
    }