[Ietf-calsify] RDATE Question was (rfc 2445 - recurrence set, suggested rewording)

[George Sexton]

The wording for RDATE and EXDATE is very similar and it's raised a 
question in my mind.

Is it required to have a DTSTART entry for RDATE events? In otherwords, 
if I have 3 events

May 1, May 5, and May 7

Should it be:

DTSTART;VALUE=DATE:20060501
RDATE;VALUE=DATE:20060505,20060507

or is

RDATE;VALUE=DATE:20060501,20060505,20060507

sufficient?

The reason I'm asking is the purpose in 4.8.5.3 states:

Purpose: This property defines the list of date/times for a recurrence set.

"the" seems to say it is sufficient by itself, while the description (as 
in EXDATE) references "the initial "DTSTART"" property.


Andrew N Dowden wrote:
> 4.8.5.1 Exception Date/Times  (EXDATE)
>
>    .. The recurrence set is the complete set of
>    recurrence instances for a calendar component. The recurrence set is
>    generated by considering the initial "DTSTART" property along with
>    the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained
>    within the iCalendar object. The "DTSTART" property defines the first
>    instance in the recurrence set. Multiple instances of the "RRULE" and
>    "EXRULE" properties can also be specified to define more
>    sophisticated recurrence sets. The final recurrence set is generated
>    by gathering all of the start date-times generated by any of the
>    specified "RRULE" and "RDATE" properties, and then excluding any
>    start date and times which fall within the union of start date and
>    times generated by any specified "EXRULE" and "EXDATE" properties.
>    This implies that start date and times within exclusion related
>    properties (i.e., "EXDATE" and "EXRULE") take precedence over those
>    specified by inclusion properties (i.e., "RDATE" and "RRULE"). Where
>    duplicate instances are generated by the "RRULE" and "RDATE"
>    properties, only one recurrence is considered. Duplicate instances
>    are ignored.
>   

-- 
George Sexton
MH Software, Inc.
Voice: +1 303 438 9585
URL:   http://www.mhsoftware.com/