def merge_search_result_word_matches result, class_name, ids
      if result.has_key? class_name
        result[class_name] = result[class_name] & ids
      else
        result[class_name] = ids
      end
    end
def merge_search_result_word_matches result, class_name, ids
      if result.has_key? class_name
        result[class_name] = result[class_name] & ids
      else
        result[class_name] = ids
      end
    end
Merges the given posable object ids for a single query word into the given search result.
 Helper method for :search_words.