Subject: RFC 2445: UNTIL & TZID

From: [email-masked]
Date: Fri, 30 Jun 2000 10:37:20 -0400

Just wanted to get some group clarification about something in RFC 2445 
with respect to UNTILs on RRULE/EXRULEs.  According to RFC 2445:

     recur      = "FREQ"=freq *(

                ; either UNTIL or COUNT may appear in a 'recur',
                ; but UNTIL and COUNT MUST NOT occur in the same 'recur'

                ( ";" "UNTIL" "=" enddate ) /
...
     enddate    = date
     enddate    =/ date-time            ;An UTC value

and

   The UNTIL rule part defines a date-time value which bounds the
   recurrence rule in an inclusive manner. If the value specified by
   UNTIL is synchronized with the specified recurrence, this date or
   date-time becomes the last instance of the recurrence. If specified
   as a date-time value, then it MUST be specified in an UTC time
   format

This last bit is a bit at odds with the rest of the behaviour for a 
recurrence rule.  For other value parts, if they are not specified they 
are inherited from the DTSTART (ie: the start time, day and date, etc). It 
is perfectly acceptable to have:

DTSTART;TZID="US-Eastern":20000629T090000
RRULE:FREQ=Weekly;UNTIL=20001224T130000Z

but Im curious _why_ the following would not also be allowed:

DTSTART;TZID="US-Eastern":20000629T090000
RRULE:FREQ=Weekly;UNTIL=20001224T090000

IFF the DTSTART had a TZID that could be inherited??  Along the same vein, 
_why_ did we disallow:

DTSTART;TZID="US-Eastern":20000629T090000
RRULE;TZID="US-Eastern":FREQ=Weekly;UNTIL=20001224T090000

I dont see any discussion of this in our archives and its a bee in my 
bonnet as I dive deeper...  Anyone care to enlighten me or voice any 
opinion as to whether we should consider updating RFC 2445 to allow for 
TZID specification or inheritance?  (If there are no objections I move 
that we a change that Ill provide to the effect that it is allowed...)

Bruce
===========================================================================
Bruce Kahn                                INet: [email-masked]
Iris Associates                          Phone: 978.392.5335
Westford, MA, USA 01886                    FAX: and nothing but the FAX...
Standard disclaimers apply, even where prohibited by law...