(define-syntax define-magick-image-op (syntax-rules () ((define-magick-image-op (scheme-name object . rest) (c-name . c-args)) (define (scheme-name object . rest) (unless ((foreign-lambda bool c-name . c-args) object . rest) (abort (magick-get-exception object)) #t))))) (define-magick-image-op (magick-read-image wand filename) (MagickReadImage magickwand (const c-string)))