3 files changed, 21 insertions, 7 deletions
diff --git a/module/vcomponent/recurrence/generate.scm b/module/vcomponent/recurrence/generate.scm
index b498e033..33f86e3d 100644
--- a/module/vcomponent/recurrence/generate.scm
+++ b/module/vcomponent/recurrence/generate.scm
@@ -217,7 +217,9 @@
          [(BYHOUR) (to-dt (set (hour t) value))]
          [(BYMINUTE) (to-dt (set (minute t) value))]
          [(BYSECOND) (to-dt (set (second t) value))]
-         [else (error "Unrecognized by-extender" key)])))
+         [else (scm-error 'wrong-type-arg "update"
+                          "Unrecognized by-extender ~s"
+                          key #f)])))
    date-object
    extension-rule))
 
diff --git a/module/vcomponent/recurrence/internal.scm b/module/vcomponent/recurrence/internal.scm
index b4f09d92..ae521d77 100644
--- a/module/vcomponent/recurrence/internal.scm
+++ b/module/vcomponent/recurrence/internal.scm
@@ -5,6 +5,7 @@
   #:use-module ((vcomponent base) :select (prop))
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-9 gnu)
+  #:use-module (ice-9 format)
   #:use-module (hnh util)
   )
 
@@ -46,11 +47,14 @@
         wkst)
 (export! count)
 
+;; Interval and wkst have default values, since those are assumed
+;; anyways, and having them set frees us from having to check them at
+;; the use site.
 (define*-public (make-recur-rule
                  key:
-                 freq until count interval bysecond byminute byhour
+                 freq until count (interval 1) bysecond byminute byhour
                  byday bymonthday byyearday byweekno bymonth bysetpos
-                 wkst)
+                 (wkst monday))
   ;; TODO possibly validate fields here
   ;; to prevent creation of invalid rules.
   ;; This was made apparent when wkst was (incorrectly) set to MO,
diff --git a/module/vcomponent/recurrence/parse.scm b/module/vcomponent/recurrence/parse.scm
index 3477f6d4..d45cedf9 100644
--- a/module/vcomponent/recurrence/parse.scm
+++ b/module/vcomponent/recurrence/parse.scm
@@ -51,7 +51,9 @@
 
 (define-macro (quick-case key . cases)
   (let ((else-clause (or (assoc-ref cases 'else)
-                         '(error "Guard failed"))))
+                         '(scm-error 'misc-error "quick-case"
+                                     "Guard failed"
+                                     #f #f))))
     `(case ,key
        ,@(map (match-lambda
                 ((key guard '=> body ...)
@@ -72,6 +74,12 @@
                  `(else ,@body)))
               cases))))
 
+(define* (string->number/throw string optional: (radix 10))
+  (or (string->number string radix)
+      (scm-error 'wrong-type-arg
+                 "string->number/throw"
+                 "Can't parse ~s as number in base ~a"
+                 (list string radix) (list string radix))))
 
 ;; RFC 5545, Section 3.3.10. Recurrence Rule, states that the UNTIL value MUST have
 ;; the same type as the DTSTART of the event (date or datetime). I have seen events
@@ -92,8 +100,8 @@
                  (parse-ics-datetime val)))
          (day (rfc->datetime-weekday (string->symbol val)))
          (days (map parse-day-spec (string-split val #\,)))
-         (num  (string->number val))
-         (nums (map string->number (string-split val #\,))))
+         (num  (string->number/throw val))
+         (nums (map string->number/throw (string-split val #\,))))
 
         ;; It's an error to give BYHOUR and smaller for pure dates.
         ;; 3.3.10. p 41
@@ -123,7 +131,7 @@
           (else o)))))
 
    ;; obj
-   (make-recur-rule interval: 1 wkst: mon)
+   (make-recur-rule)
 
    ;; ((key val) ...)
    (map (cut string-split <> #\=)