static PTElement ai_parseToTreeWithGuessing(S input) {
    L<S> words = ai_uncategorizedWordsInSentence(input);
  //print("Have " + n2(words, "unknown word"));
  
  new AI_BottomUpParser1 parser;
  parser.wordsToCategories = DerivedMap(ai_wordToCategories());
  Map<S, Map<S, Double>> guessMap = new HashMap;
  temp tempSetThreadLocal(ai_getWordToCategoryWeight_map, guessMap);
  for (S word : words) {
    Map<S, Double> map = ai_guessCategoriesForUnknownWord_weighted(word);
    guessMap.put(word, map);
    parser.wordsToCategories.put(word, keys(map));
  }
  ret ai_parseBottomUpToTree(parser, input);
}