code: public void addShift(int state, int sym, int nextState) {
          int idx;
  
          idx = state * symbolCount + sym;
          if (values[idx] != NOT_SET) {
              throw new IllegalStateException();
          }
          values[idx] = createValue(Parser.SHIFT, nextState);
      }
docs: Cannot have conflicts. @param  sym  may be a nonterminal