Megatest

  (time->string
   (seconds->local-time sec) "%yww%V.%w"))

(define (seconds->year-work-week/day-time sec)
  (time->string
   (seconds->local-time sec) "%Yww%V.%w %H:%M"))

(define (seconds->year-week/day-time sec)
  (time->string
   (seconds->local-time sec) "%Yw%V.%w %H:%M"))

(define (seconds->quarter sec)
  (case (string->number
	 (time->string 
	  (seconds->local-time sec)
	  "%m"))
    ((1 2 3) 1)
    ((4 5 6) 2)
    ((7 8 9) 3)
    ((10 11 12) 4)
    (else #f)))

;; given span of seconds tstart to tend
;; find start time to mark and mark delta
;;
(define (common:find-start-mark-and-mark-delta tstart tend)
  (let* ((deltat   (- tend tstart))
	 (result   #f)
	 (min      60)
	 (hr       (* 60 60))
	 (day      (* 24 hr))
	 (yr       (* 365 day)) ;; year
	 (mo       (/ yr 12))
	 (wk       (* day 7)))
    (for-each
     (lambda (max-blks)
       (for-each
	(lambda (span) ;; 5 2 1
	  (if (not result)
	      (for-each 
	       (lambda (timeunit timesym) ;; year month day hr min sec
		 (if (not result)
		     (let* ((time-blk (* span timeunit))
			    (num-blks (quotient deltat time-blk)))
		       (if (and (> num-blks 4)(< num-blks max-blks))
			   (let ((first (* (quotient tstart time-blk) time-blk)))
			     (set! result (list span timeunit time-blk first timesym))
			     )))))
	       (list yr mo wk day hr min 1)
	       '(     y  mo w  d   h  m   s))))
	(list 8 6 5 2 1)))
     '(5 10 15 20 30 40 50 500))
    (apply values result)))
	    
	  

;;======================================================================
;; C O L O R S
;;======================================================================
      
(define (common:name->iup-color name)
  (case (string->symbol (string-downcase name))

							fill-color: stdcolor
							line-color: stdcolor))
				     (print "ERROR: curr-tval is not > last-tval; curr-tval " curr-tval ", last-tval " last-tval))))
			   next)
			 ;; for init create vector tstart,0
			 #f ;; (vector tstart minval minval)
			 dat)
			 (vg:add-obj-to-comp
			  cmp
			  (vg:make-text-obj (- (tfn tstart) 10)(- lly 10)(seconds->year-week/day-time tstart)))
			 (let*-values (((span timeunit time-blk first timesym) (common:find-start-mark-and-mark-delta tstart tend)))
			   (let loop ((mark  first)
				      (count 0))
			     (let* ((smark (tfn mark))           ;; scale the mark
				    (mark-delta (quotient (- mark tstart) time-blk)) ;; how far from first mark
				    (label      (conc mark-delta timesym)))
			       (if (> count 2)
				   (begin
				     (vg:add-obj-to-comp
				      cmp
				      (vg:make-rect-obj (- smark 1)(- lly 2)(+ smark 1) lly))
				     (vg:add-obj-to-comp
				      cmp
				      (vg:make-text-obj (- smark 1)(- lly 10) label))))
			       (if (< mark (- tend time-blk))
				   (loop (+ mark time-blk)(+ count 1))))))
			   
			;; (for-each
			 ;; (for-each
			;;  (lambda (dpt)
			;;    (let* ((tval  (vector-ref dpt 0))
			;; 	  (yval  (vector-ref dpt 2))
			 ;; 	  (yval  (vector-ref dpt 2))
			;; 	  (stval (tfn tval))
			;; 	  (syval (yfunc yval)))
			;;      (vg:add-obj-to-comp
			;;       cmp 
			;;       (vg:make-rect-obj (- stval 2) lly (+ stval 2)(+ lly (* yval yscale))
			;; 			fill-color: stdcolor))))
			;;  dat)