DouKaku?

(use srfi-1)
(use srfi-19)
(define (week-days year month day)
  (let* ((now (make-date 0 0 0 0 day month year
                         (date-zone-offset (current-date))))
         (start (- (date->modified-julian-day now) (date-week-day now) -1)))
    (map (lambda (x)
           (let* ((date (modified-julian-day->date (+ start x)))
                  (dow (list-ref '("日""月""火""水""木""金""土")
                                 (date-week-day date)))
                  (fmt (date->string (modified-julian-day->date (+ start x))
                                     #`"~1(,dow)")))
             fmt))
         (iota 5))))


;; 出力例
gosh> (for-each print (week-days 2007 7 6))
2007-07-02(月)
2007-07-03(火)
2007-07-04(水)
2007-07-05(木)
2007-07-06(金)

gosh> (for-each print (week-days 2007 7 31))
2007-07-30(月)
2007-07-31(火)
2007-08-01(水)
2007-08-02(木)
2007-08-03(金)

gosh> (for-each print (week-days 2007 12 31))
2007-12-31(月)
2008-01-01(火)
2008-01-02(水)
2008-01-03(木)
2008-01-04(金)