Created
September 22, 2015 19:10
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#lang racket | |
(define (Pt x y) | |
(let ([self 0]) | |
(begin | |
(define (obj method) | |
(case method | |
[("getX") (lambda () x)] | |
[("getY") (lambda () y)] | |
[("moveX") (lambda (newx) (Pt (+ newx ((self "getX"))) y))])) | |
(set! self obj) | |
obj))) | |
(define pt (Pt 6 7)) | |
((pt "getX")) | |
((pt "getY")) | |
(define pt2 ((pt "moveX") 67)) | |
(list ([pt2 "getX"]) ([pt2 "getY"])) |
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