private boolean processExprentList(List<Exprent> lst) {

    boolean result = false;

    for (int i = 0; i < lst.size(); i++) {
      Exprent exprent = lst.get(i);
      exprentReplaced = false;

      Exprent retexpr = processExprentRecursive(exprent);
      if (retexpr != null) {
        lst.set(i, retexpr);

        result = true;
        i--; // process the same exprent again
      }

      result |= exprentReplaced;
    }

    return result;
  }
private boolean processExprentList(List<Exprent> lst)