do(
  define(sum,  # function
    fun(nums, other,
      do(
         print(other),
         define(i, 0),
         define(sum, 0),
         while(<(i, length(nums)),
           do(define(sum, +(sum, element(nums, i))),
              define(i, +(i, 1))
           )
         ),
         sum
      )
   )
 ),
 print(sum(array(1, 2, 3), 4))
)