static FullPhraseCache makeFullPhraseCache(Iterable<S> phrases) {
  new FullPhraseCache cache;
  if (phrases != null) for (S s : phrases)
    cache.add(s);
  ret cache;
}

static FullPhraseCache makeFullPhraseCache(S... phrases) {
  ret makeFullPhraseCache(asList(phrases));
}