code: public OperatorTable<T> infixn(
        Parser<? extends BiFunction<? super T, ? super T, ? extends T>> parser, int precedence) {
      ops.add(new Operator(parser, precedence, Associativity.NASSOC));
      return this;
    }
docs: Adds an infix non-associative binary operator.
  
  @param parser the parser for the operator.
  @param precedence the precedence number.
  @return this.