static void ai_spec_daysOld() {
  for (S pat : ai_texts_unquote(".", "Look for answer pattern", "$X")) {
    SS match = matchDollarVarsIC("$X is $Y days old", pat);
    continue unless match != null;
    S who = match.get("$X");
    for (S dayBorn : filterMatchDollarX_IC("born on day $X", ai_texts(who, "was", "$Y"))) {
      S today = matchDollarX_IC("day $X", ai_text("it", "today is", "$X"));
      if (isInteger(today) && isInteger(dayBorn)) {
        long age = parseLong(today)-parseLong(dayBorn);
        post("Answer", "is", who + " is " + age + " days old");
      }
    }
  }
}