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|
(define-module (vcalendar recur)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-41)
#:use-module (vcalendar)
)
(define s "FREQ=WEEKLY;UNTIL=20191130")
(define (generate-kv-pairs str)
(map (cut string-split <> #\=)
(string-split str #\;)))
(define upstring->symbol (compose string->symbol string-upcase))
(define-syntax-rule (ensure key val test)
((key)
(let ((v val))
(if (test v)
v
(throw 'bad-value key val))
)))
#;
(let ((key 'FREQ)
(val-base 'HOURLY))
(case key
(FREQ (upstring->symbol val-base)
(memv <> '(SECONDLY MINUTELY HOURLY DAILY
WEEKLY MONTHLY YEARLY)))))
(define-immutable-record-type <recur-rule>
(make-recur-rules freq until count interval)
recur-rule?
(freq get-freq set-freq)
(until get-until set-until)
(count get-count set-count)
(interval get-interval set-interval)))
(let ((s->n string->number))
(reduce (lambda (kv rule)
(let ((key (upstring->symbol (car kv)))
(val-base (cadr kv)))
(case key
((FREQ)
(set-freq rule
(ensure (upstring->symbol val-base)
(cut memv <>
'(SECONDLY MINUTELY HOURLY DAILY
WEEKLY MONTHLY YEARLY)))))
((UNTIL)
(set-until rule (parse-datetime val-base)))
((COUNT) (set-count rule (s->n val-base)))
((INTERVAL) (set-internal rule (s->n val-base)))
((BYSECOND) (let ((s (s->n val-base)))
(<= 0 s 60)))
((BYMINUTE) (let ((m (s->n val-base)))
(<= 0 m 59)))
((BYHOUR) (let ((h (s->n val-base)))
(<= 0 h 23)))
#|
((BYDAY) #; TODO )
((BYMONTHDAY) #; TODO)
((BYYEARDAY) )
((BYWEEKNO) )
((BYMONTH) )
((BYSETPOS) )
((WKST) )
|#
(else 'err))))
(generate-kv-pairs s)))
#|
Each recuring event should be expanded to a stream of all it's occurances.
The first instance of the event is at DTSTART,
times for following instances are calculating according to the DSL below.
3.3.10. Recurrence Rule
Value Name: RECUR
|#
#|
byseclist = ( seconds *("," seconds) )
seconds = 1*2DIGIT ;0 to 60
byminlist = ( minutes *("," minutes) )
minutes = 1*2DIGIT ;0 to 59
byhrlist = ( hour *("," hour) )
hour = 1*2DIGIT ;0 to 23
bywdaylist = ( weekdaynum *("," weekdaynum) )
weekdaynum = [[±] ordwk] weekday
ordwk = 1*2DIGIT ;1 to 53
weekday = "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA"
;Corresponding to SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY,
;FRIDAY, and SATURDAY days of the week.
Desruisseaux Standards Track [Page 39]
RFC 5545 iCalendar September 2009
bymodaylist = ( monthdaynum *("," monthdaynum) )
monthdaynum = [±] ordmoday
ordmoday = 1*2DIGIT ;1 to 31
byyrdaylist = ( yeardaynum *("," yeardaynum) )
yeardaynum = [±] ordyrday
ordyrday = 1*3DIGIT ;1 to 366
bywknolist = ( weeknum *("," weeknum) )
weeknum = [±] ordwk
bymolist = ( monthnum *("," monthnum) )
monthnum = 1*2DIGIT ;1 to 12
bysplist = ( setposday *("," setposday) )
setposday = yeardaynum
|#
|
