static L<WeightedProduction> ai_buParser_parseWeightedProductions() {
  new L<WeightedProduction> l;
  for (S s : mL(ai_language() + " bottom-up groupings")) {
    S sWeight = trailingAngleBracketStuff(s);
    double weight = nempty(sWeight) ? parseDouble(sWeight) : 1.0;
    s = dropTrailingAngleBracketStuff(s);
    L<S> tok = javaTokWithAngleBracketsC(s);
    if (l(tok) == 5)
      l.add(WeightedProduction(tok.get(0), tok.get(2), tok.get(4), weight));
    else if (l(tok) == 3)
      l.add(WeightedProduction(tok.get(0), tok.get(2), weight));
  }
  ret l;
}