こんな風に書くのめんどいよね。 (or (equal? x #\a) (equal? x #\b) (equal? x #\c)) just を書いて…… (define* (just x #:optional (judge? equal?)) (lambda (other) (judge? x other))) one-of をこういう風に書いたら、 (define (one-of . args) (lambd…