Add final-event-occurence procedure.

2 files changed, 14 insertions, 1 deletions

diff --git a/module/datetime/zic.scm b/module/datetime/zic.scm
index e9be7701..52457ada 100644
--- a/module/datetime/zic.scm
+++ b/module/datetime/zic.scm
@@ -102,7 +102,7 @@
   (stdoff zone-entry-stdoff)                   ; <timespec>
   (rule zone-entry-rule)                       ; #f | symbol | <timespec>
   (format zone-entry-format)                   ; string
-  (until zone-entry-until))                    ; <datetime>
+  (until zone-entry-until))                    ; <datetime> | #f
 
 (export zone-entry? zone-entry-stdoff zone-entry-rule zone-entry-format zone-entry-until)
 
diff --git a/module/vcomponent/recurrence/generate-alt.scm b/module/vcomponent/recurrence/generate-alt.scm
index 7337ddaa..d48e471d 100644
--- a/module/vcomponent/recurrence/generate-alt.scm
+++ b/module/vcomponent/recurrence/generate-alt.scm
@@ -292,6 +292,19 @@
                                       date-stream))]
           [else date-stream])))
 
+
+(define-public (final-event-occurence event)
+  (define rrule  (parse-recurrence-rule
+                  (attr event 'RRULE)
+                  (if (date? (attr event 'DTSTART))
+                      parse-ics-date parse-ics-datetime)))
+
+  (if (or (count rrule) (until rrule))
+      (let ((instances (rrule-instances event)))
+        (stream-ref instances (1- (stream-length instances))))
+      #f))
+
+
 (define (generate-recurrence-set base-event)