16 lines
384 B
Scheme
16 lines
384 B
Scheme
(define (find pred lst)
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(let loop ((lst lst))
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(if (null? lst) #f
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(if (pred (car lst)) (car lst)
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(loop (cdr lst))))))
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(define (filter pred lst)
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(let loop ((lst lst))
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(if (null? lst) '()
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(if (pred (car lst))
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(cons (car lst) (loop (cdr lst)))
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(loop (cdr lst))))))
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(define (append-map f lst)
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(apply append (map f lst)))
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