函数式编程入门 lisp

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#lang slideshow

(define c (circle 10))

(define r (rectangle 10 20))

;定义一个调用函数

(define (square n)

  (filled-rectangle n n))

;局部绑定

(define (four p)

  (define two-p (hc-append p p))

  (vc-append two-p two-p))

;使用let进行绑定

(define (checker p1 p2)

  (let
([p12 (hc-append p1 p2)]

        [p21(hc-append p2 p1)])

    (vc-append p12 p21)))