example of using 'foldl' to eliminate nested calls

foldl-example.rkt

;; a state is a number

;; add the two numbers to the state
(define (state-update state a b)
  (+ state a b))

(define my-state 234)


;; either:
(state-update
 (state-update
  (state-update
   (state-update
    (state-update
     (state-update
      (state-update
       my-state 0 15) 1 79) 7 98) 8 34) 8 97) 4 87) 10 278)

;; OR

(define (state-update/l input-list state)
  (state-update state (first input-list) (second input-list)))

(foldl
 state-update/l
 my-state
 (list (list 0 15)
       (list 1 79)
       (list 7 98)
       (list 8 34)
       (list 8 97)
       (list 4 87)
       (list 10 278)))

;; OR, even shorter, using list abbreviations

(foldl
 state-update/l
 my-state
 '((0 15)
   (1 79)
   (7 98)
   (8 34)
   (8 97)
   (4 87)
   (10 278)))