calling.scm

(define (delegating-getter-and-setter-syntax  vars get-delegate set-delegate)
  (let ((args-name (gensym "args"))
	(an-arg-name (gensym "an-arg"))
	(new-val-name (gensym "new-value"))
	(loop-name (gensym "loop"))
	(kws (map symbol->keyword vars)))
    (list `(lambda ,args-name
	     (let ,loop-name ((,args-name ,args-name))
		  (if (null? ,args-name)
		      (append!
		       ,(if (null? kws)
			    ''()
			    `(let ((all-vals (,loop-name ',kws)))
			       (let ,loop-name ((vals all-vals)
						(kws ',kws))
				    (if (null? vals)
					'()
					`(,(car kws) ,(car vals) ,@(,loop-name (cdr vals) (cdr kws)))))))
		       (,get-delegate))
		      (map (lambda (,an-arg-name)
			     (case ,an-arg-name
			       ,@ (append
				   (map (lambda (kw v) `((,kw) ,v)) kws vars)
				   `((else (car (,get-delegate ,an-arg-name)))))))
			   ,args-name))))

	  `(lambda ,args-name
	     (let ,loop-name ((,args-name ,args-name))
		  (or (null? ,args-name)
		      (null? (cdr ,args-name))
		      (let ((,an-arg-name (car ,args-name))
			    (,new-val-name (cadr ,args-name)))
			(case ,an-arg-name
			  ,@ (append
			      (map (lambda (kw v) `((,kw) (set! ,v ,new-val-name))) kws vars)
			      `((else  (,set-delegate ,an-arg-name ,new-val-name)))))
			(,loop-name (cddr ,args-name)))))))))