================================================================================
Addition is left associative
================================================================================

1 + 1 + 1 + 1

--------------------------------------------------------------------------------

(expression
  (addition
    (expression
      (addition
        (expression
          (addition
            (expression
              (number))
            (expression
              (number))))
        (expression
          (number))))
    (expression
      (number))))

================================================================================
Superaddition still parses
================================================================================

1 + + 1

--------------------------------------------------------------------------------

(expression
  (superaddition
    (expression
      (number))
    (expression
      (number))))
