Subject: CAP-12-a: 8.30 RECUR-ACCEPTED

From: [email-masked]
Date: Wed, 3 Sep 2003 16:55:27 -0400

I see that we have a Section 8.30 RECUR-ACCEPTED Property that defined as:

   Purpose: This property specifies if the endpoint supports recurring
   instances.
...
   Description: Indicates if recurrence rules are supported.  If FALSE
   then the endpoint can not process any kind of recurring rules.

The Purpose text talks about general recurrence but the Description text 
talks about recurrence rules.  This is a disjoin since:

A) Recurrence also involves RDATEs/EXDATEs and not just RRULEs/EXRULEs and 

B) I think there needs to be some distinction of any recurrence grammar 
support versus Recurrence Rule vs Exception Rule support (at least in the 
2nd bit of text)

Just because an implementation supports some forms of the recurrence 
grammar (iCalendar, Section 4.3.10 Recurrence Rule) does not mean that it 
supports both the RRULE (iCalendar, Section 4.8.5.4 Recurrence Rule) and 
EXRULE (iCalendar, Section 4.8.5.2 Exception Rule) forms.  Some 
implemenations may not support the EXRULE but this is not conveyable in 
CAP currently.  (Supporting EXRULE and not RRULE is a crazy combination to 
me but perhaps its logical to some...)  Anyway, the text above seems to be 
an indication of general Recurrence Rule support rather than explicit 
RRULE or EXRULE support. 

We need to fix the disjoin between the described Purpose and the actual 
Description and we need to make the "rule" distiction clearer.  Likely we 
will also need to make a finer distinction between RRULE & EXRULE. 

The original intent of this was not just to convey recurrence grammar 
support but general recurrence support (for PD or simple implementations 
that didnt want to have the complexity necessary for repeating instances) 
so I suggest that Description gets reworked to be more akin to the 
Purpose's intent rather than its current intent.  If we want to drill down 
to recurrence rule support, that should be done separately and with 
RRULE/EXRULE distinction included.

Bruce
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---

From: Doug Royer <[email-masked]>
Date: Wed, 03 Sep 2003 16:06:22 -0600

> A) Recurrence also involves RDATEs/EXDATEs and not just RRULEs/EXRULEs and

1) It does not say 'RRULE' or 'EXRULE'.

2) Do you have a suggestion as to what it should say?

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From: [email-masked]
Date: Thu, 4 Sep 2003 09:07:05 -0400

> 1) It does not say 'RRULE' or 'EXRULE'.

Correct.  The text under Description says "recurrence rules".  This implys 
RRULEs (iCalendar, Section 4.8.5.4 Recurrence Rule) and thus excludes 
EXRULES.  Im saying that this is a mistake.  Not every implementation will 
support both RRULEs and EXRULEs so the draft needs to be hip to this and 
not totally ignore both.

> 2) Do you have a suggestion as to what it should say?

First we need to answer the discrepancy between the Purpose and the 
Description.  Then we will have a better idea of what text to add.

In case you missed that point, the Purpose clearly says "supports 
recurring _instances_" and the Description says "recurrence _rules_ are 
supported".  These are NOT the same.  Recurring _instances_ include RDATEs 
or put another way, repeating instances of any kind.  Recurring _rules_ 
are just RRULEs and NOT RDATEs (or EXRULES or EXDATEs). 

Unless CAP is going to be indeterminate on the support of RDATEs, EXRULEs 
and EXDATEs then something needs to be changed. 

So the question to answer FIRST is "Does RECUR-ACCEPTED refer to all kinds 
of recurrence or just to recurrence grammars?"  From there we can move 
along to some better text.  I for one think that it implys all recurrence 
but Im sure others may have other ideas.  Untill we have concensus on the 
intent, any proposed text is a waste of time.

FYI: Not all implementations support RDATEs but do support RRULEs.  If I 
recall correctly, Outlook does/did not support RDATEs but they do support 
RRULEs (at least thats what I recall from some testing we did here or at a 
CalConnect.) so do not assume that every implementation supports every 
form of repeating instance.

Bruce

---

From: Doug Royer <[email-masked]>
Date: Thu, 04 Sep 2003 09:11:20 -0600

[email-masked] wrote:
> Correct.  The text under Description says "recurrence rules".  This 
> implys RRULEs (iCalendar, Section 4.8.5.4 Recurrence Rule) and thus 
> excludes EXRULES. 

Why do you fell that EXRULES are excluded? Where does it say
that?

> Im saying that this is a mistake.  Not every 
> implementation will support both RRULEs and EXRULEs so the draft needs 
> to be hip to this and not totally ignore both.

Again - do you have a suggestion?

> Description.  Then we will have a better idea of what text to add.

Again - do you have a suggestion?

--

---

From: [email-masked]
Date: Thu, 4 Sep 2003 12:10:03 -0400

> Why do you fell that EXRULES are excluded? Where does it say

Because the text says "recurrence rules" and not "recurrence and exclusion 
rules".  An EXRULE is an _exclusion_ rule, RRULE is a _recurrence_ rule. 
Both are examples of properties that use the recurrence rule grammar.  CAP 
is unclear on which its referring to and some could incorrectly infer the 
wrong choice from what we intended (more easily than misunderstanding the 
meaning of "original").  If you do not understand the difference then 
perhaps we need to get someone to help co-edit CAP who  does.

> Again - do you have a suggestion?

Doug seems to have a perchant for missing points.  I just told you my 
suggestion: we need to answer the discrepancy between Purpose and 
Description.

Is the purpose of RECUR-ACCEPTED to be all different kinds of recurrence 
or just recurrence rules (RRULEs)?  I suspect the Purpose is accurate and 
Description is just poorly phrased but thats just me.   Anyone think that 
the Description is correct and that Purpose is poorly phrased?

Bruce

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From: Doug Royer <[email-masked]>
Date: Thu, 04 Sep 2003 12:01:01 -0600

[email-masked] wrote:

> suggestion: we need to answer the discrepancy between Purpose and 

So you are proposing we change the text to:

	"we need to answer the discrepancy between Purpose and
	Description."

No.

So - do you have a proposal?

--

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From: [email-masked]
Date: Thu, 4 Sep 2003 18:29:55 -0400

>    "we need to answer the discrepancy between Purpose and

Correct: No.  Im not sure if I should propose getting a co-editor or not 
since you seem to have a knack for missing points.

I propose that the WG decide if the intent of the RECUR-ACCEPTED property 
is correctly defined as (A) "This property specifies if the endpoint 
supports recurring instances." (any kind of recurrence) or as (B) "This 
property specifies if the endpoint supports recurring rules." (RRULEs 
only)

I suggest (A) is correct and (B) is incorrect.  If we opt for (A) then 
Description needs to be changed to be:

   Description: Indicates if recurrence instances are supported. If FALSE
   then the endpoint can not process any kind of recurring rules.

If we opt for (B) then Description is ok and Purpose needs to be changed 
to:

   rules.

No matter if we choose (A) or (B), the property is incomplete in that it 
is unable to convey the ability/inability for a CS to deal with RDATEs, 
EXRULEs and EXDATEs. 

As noted earlier, not all engines that support RRULEs support RDATEs and 
supporing RRULEs/RDATEs is orthogonal to supporting EXRULEs/EXDATEs.   As 
such CAP needs some way for this ability/inability to be conveyed clearly 
for each kind of recurrence/exclusion.  Depending on how we resolve 
(A)/(B) above, I can better propose how to fix the other bits.

Bruce
Warning: Dates in Calendar are closer than they appear.