# File lib/parser/builders/default.rb, line 874
    def unary_op(op_t, receiver)
      case value(op_t)
      when '+', '-'
        method = value(op_t) + '@'
      else
        method = value(op_t)
      end

      n(:send, [ receiver, method.to_sym ],
        send_unary_op_map(op_t, receiver))
    end