code: func (doc *document) someTitle() string {
  	if doc.title != "" {
  		return doc.title
  	}
  	if doc.tags.isEmpty() {
  		return fmt.Sprintf("Doc Ref %s", doc.permanode)
  	}
  	return strings.Join(doc.tags, ",")
  }
docs: // SomeTitle returns this struct's title or, failing that, its tags -
  // and even failing that, its IntID