[The Little Schemer]5章の途中まで

「The Little Schemer」

昨日の続き

;((5. *Oh My Gawd*:It's Full of Stars) 80) (define rember*   (lambda (a l)     (cond      ((null? l) '())      ((atom? (car l))       (cond        ((eq? a (car l))         (rember* a (cdr l)))        (else (cons (car l)                    (rember* a (cdr l))))))      (else (cons (rember* a (car l))                  (rember* a (cdr l)))))))   (define insertR*   (lambda (new old l)     (cond      ((null? l) '())      ((atom? (car l))       (cond        ((eq? old (car l))         (cons (car l)               (cons new                     (insertR* new old (cdr l)))))        (else (cons (car l)                    (insertR* new old (cdr l))))))      (else (cons (insertR* new old (car l))                  (insertR* new old (cdr l)))))))   (define occur*   (lambda (a l)     (cond      ((null? l) 0)      ((atom? (car l))       (cond        ((eq? a (car l))         (add1 (occur* a (cdr l))))        (else (occur* a (cdr l)))))      (else (o+ (occur* a (car l))                (occur* a (cdr l)))))))

 

なんだか、だいぶスラスラ書けるようになっててうれしいなぁー。まぁまだこんな簡単な問題だからだけれども。