cut-sc-ver.scm

(define-syntax cut%
  (sc-macro-transformer
   (lambda (form env)
     (letrec ((map-msc
	       (lambda (x)
		 (map (lambda (ex)
			(make-syntactic-closure env '(<> <...>) ex))
		      x))))
       (let ((slots (cadr form))
	     (combi (caddr form))
	     (se (cdddr form)))
	 (cond ((null? se)
		(let ((slots (reverse slots))
		      (combi (reverse combi)))
		  `(lambda ,slots ((begin ,(car combi)) ,@(cdr combi)))))
	       ((eq? (car se) '<...>)
		(let ((slots (fold-right cons
					 'rest-slot
					 (reverse slots)))
		      (combi (reverse (cons 'rest-slot combi))))
		  `(lambda ,slots (apply ,@combi))))
	       ((eq? (car se) '<>)
		(let ((x (make-syntactic-closure env '() 'x)))
		  (let ((slots (cons x (map-msc slots)))
			(combi (cons x (map-msc combi))))
		    `(cut% ,slots ,combi ,@(cdr se)))))
	       (else
		(let ((slots (map-msc slots))
		      (combi (map-msc (cons (car se) combi))))
		  `(cut% ,slots ,combi ,@(cdr se))))))))))