srecord RecursiveMatcher(IMatchFunction matchF) implements IMatchFunction {
  public bool get(O pat, O real, Map map) {
    if (pat instanceof WordSequence) {
      if (!real << WordSequence) false;
      ret matchWordSequence(pat/WordSequence, real/WordSequence, this, map);
    }
    ret matchF.get(pat, real, map);
  }
}