================================================================================
Variables
================================================================================

let top_50 = (
  from employees
  sort salary
  take 50
  aggregate {total_salary = sum salary}
)

from top_50

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

(program
  (variable
    (keyword_let)
    (identifier)
    (pipeline
      (from
        (keyword_from)
        (identifier))
      (transforms
        (sorts
          (keyword_sort)
          (identifier))
        (takes
          (keyword_take)
          (integer))
        (aggregate
          (keyword_aggregate)
          (assignment
            (field
              (identifier))
            (keyword_sum)
            (field
              (identifier)))))))
  (pipeline
    (from
      (keyword_from)
      (identifier))))
