(define (raise x) (apply-generic 'raise x)) ;; scheme-numberパッケージで (define (scheme-number->rational n) (make-rational n 1)) (put 'raise 'scheme-number scheme-number->rational) ;; rationalパッケージで (define (rational->real x) (/ (* …

(define (apply-generic op . args) (let ((type-tags (map type-tag args))) (define (try-coercion args tags) (if (null? tags) (error "Nomethod for these types" (list op type-tags)) (let ((new-args (map (lambda (x) (get-coercion (car tags) (ty…