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- #lang racket
- (provide obj-maker
- obj-set
- obj-show)
- (define (alist->obj alist)
- (λ key
- (if (null? key)
- alist
- (cadr (assoc (car key) alist)))))
- (define (obj-maker . fields)
- (λ inits
- (define alist (map list fields inits))
- (alist->obj alist)))
- (define (obj-set record key value)
- (define alist (record))
- (define new-alist
- (let loop ((new-list '()) (cur alist) (is-set #f))
- (if (null? cur)
- (if is-set
- new-list
- (cons (list key value) new-list))
- (let ()
- (if (eq? key (caar cur))
- (loop (cons (list key value) new-list) (cdr cur) #t)
- (loop (cons (car cur) new-list) (cdr cur) is-set))))))
- (alist->obj new-alist))
- (define (obj-show x) (x))
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