sclass FullPhraseCache {
  L<LS> phrases; // different spellings of full phrase
  Map<S, FullPhraseCache> byFirstWord = ciMap();

  void add(S phrase) {
    LS tok = javaTokNPunctuation_cached(phrase);
    if (l(tok) == 1) ret;
    add(tok, 1);
  }
  
  void add(LS tok, int idx) {
    if (idx >= l(tok)-1)
      ret with phrases.add(tok);
    FullPhraseCache subCache = getOrCreate(byFirstWord, tok.get(idx), FullPhraseCache);
    subCache.add(tok, idx+2);
  }
}