第二章习题 2.33 - 2.51 的解答。

E-2.33:

(define (accumulate op initial sequence)
  (if (null? sequence)
    initial
    (op (car sequence)
        (accumulate op initial (cdr sequence)))))

; -----------------------------------------------------------------------

(define (my-map p sequence)
  (accumulate (lambda (x y) (append (list x) y)) (list) sequence))

(define 

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