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;;;; License: CC0-1.0
(define-module (net ricketyspace sicp two thirtythree)
#:export (sicp-map
sicp-append
sicp-length))
(define (accumulate op initial sequence)
(if (null? sequence)
initial
(op (car sequence)
(accumulate op initial (cdr sequence)))))
(define (sicp-map p sequence)
(accumulate (λ (x y)
(cons (p x) y))
'() sequence))
(define (sicp-append seq1 seq2)
(accumulate cons seq2 seq1))
(define (sicp-length sequence)
(accumulate (λ (x y)
(+ 1 y))
0
sequence))
;;; Guile REPL
;;;
;;;
;;; scheme@(guile-user)> ,use (net ricketyspace sicp two thirtythree)
;;;
;;; scheme@(guile-user)> (sicp-map (λ (x) (expt 2 x)) '(1 2 3 4 5 6 7 8 9 10))
;;; $5 = (2 4 8 16 32 64 128 256 512 1024)
;;;
;;; scheme@(guile-user)> (sicp-append '(1 2 3 4 5 6 7 8 9 10) '(11 12 13 14 15 16))
;;; $7 = (1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16)
;;;
;;; scheme@(guile-user)> (sicp-length '(40 41 42 43 44 45 46 47 48 49))
;;; $11 = 10
;;;
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