sS ai_groupUsingProductions(S s, AI_BottomUpParser1 p) {
  p.parse(javaTokNPunctuation(s));
  for (AI_BottomUpParser1.Word g : p.groups()) {
    tokPrepend(p.cnc, g.wordFrom*2+1, "{");
    tokAppend(p.cnc, g.wordTo*2-1, "}");
  }
  ret join(p.cnc);
}