function hook_code($hook_short_name, $parameters_string) {
    $parameters = explode(', ', $parameters_string);
    $parameters_doc_lines = array();
    foreach ($parameters as $parameter) {
      $parameters_doc_lines[] = " * @param $parameter\n" .
                                " *   TODO: document this parameter.";
    }
    if (!empty($parameters_doc_lines)) {
      $parameters_doc = " *\n" . implode("\n", $parameters_doc_lines);
    }

    return <<<EOT
/**
 * TODO: write summary line.
 *
 * TODO: longer description.
$parameters_doc
 *
 * @return
 *   TODO: Document return value if there is one.
 */
function hook_$hook_short_name($parameters_string) {
  // TODO: write sample code.
}

EOT;
  }