[threeten-dev] Islamic calendar variants need disambiguation

[Dan Chiba]

Hi Stephen,

Thank you for the comments. For the ambiguous cases with no cv code, 
let's let it fall back to "islamic", which is the default variant Umm 
Al-Quara ("ca-islamic-cv-uaq" in CLDR). I just updated github #118 
<https://github.com/ThreeTen/threeten/issues/118> with this information.

For the chronology ID, I am not sure exactly what it is; is it an ID to 
specify a Chronology class? If it could affect Islamic calendar support, 
would you mind providing a pointer to the discussion?

Thanks,
-Dan

On 1/13/2013 2:50 PM, Stephen Colebourne wrote:
> This plan looks fine to me,
>
> There is a separate discussion around what the chronology ID will be,
> currently "Hijrah" (the strings in your email are the calendar system
> ID).
>
> I do think that it is important that if the Locale has a ca code, but
> not a cv code, then it should map to something sensible.
>
> Stephen
>
>
>
> On 12 January 2013 01:35, Dan Chiba<dan.chiba at oracle.com>  wrote:
>> For 310, we like the approach to use "islamic" for the primary variant and
>> using "islamic-xxx" for others.
>> We would like to propose a few details to fit to the CLDR ca/cv separation
>> as follows:
>>
>>   310             CLDR                  Description
>>   -------------   --------------------  ---------------------------------
>>   islamic         ca-islamic-cv-uaq     Umm Al-Qura
>>   islamic-sa      ca-islamic-cv-sa      Saudi Arabia Sighting
>>   islamic-???     ca-islamic-cv-???     "???" denotes a specific variant.
>>
>>
>> * Chronology.of() takes a 310 string. In JDK8 "islamic" and "islamic-sa" are
>> the only defined variants.
>> * Chronology.ofLocale() creates the specified variant if the locale has the
>> CLDR designation inside.
>> * The variant identifier must be in lowerecase and can be 2 to 8 letters
>> long.
>> * The IANA region codes are reserved. A region other than "sa" may have a
>> variant.
>> * 310 and CLDR plan to identify the common variants.
>>    (e.g. "kuwaiti" may be in high demand and become the next defined variant.
>> The list may grow.)
>> * Users who need a user defined variant may use a custom ID at their own
>> risk.
>>    They are encouraged to request getting the ID registered.
>> * 310 could have "islamic-uaq" as an alias of "islamicc" to match the
>> defaulting for deprecation in CLDR.
>> * 310 could have "islamic-uaq" as an alias of "islamic" to help achieve
>> consistent mapping from CLDR to 310.
>> * The registration/maintenance process is TBD.
>>
>> May I ask if this looks something we can settle this with?
>>
>> Regards,
>> -Dan
>>
>>
>> On 1/11/2013 2:01 PM, Stephen Colebourne wrote:
>>> The string can be anything you want, as its more of an Oracle
>>> requirement than mine.
>>>
>>> Personally, I would recommend that Oracle chooses a default Islamic
>>> calendar variant, so the string "islamic" maps to one of the variants.
>>> I would then have the other variants as "islamic-xxx". The ca and cv
>>> parts in the 310 calendar system id are not really relevant.
>>>
>>> Stephen
>>>
>>>
>>> On 11 January 2013 20:49, Dan Chiba<dan.chiba at oracle.com>   wrote:
>>>> Thank you very much Yoshito-san.
>>>>
>>>> Stephen, can the single string be "ca-islamic-cv-???"? Then all we need
>>>> to
>>>> do may be define the ???s?
>>>>
>>>> Regards,
>>>> -Dan
>>>>
>>>>
>>>> On 1/10/2013 5:20 PM, Stephen Colebourne wrote:
>>>>> On 10 January 2013 21:04,<yoshito_umaoka at us.ibm.com>    wrote:
>>>>>> We had a discussion about this in the CLDR TC meeting.
>>>>>> Our tentative consensus is supporting calendar variations with a new
>>>>>> extension.
>>>>>>
>>>>>> Although CLDR defines two types "islamic" and "islamicc", CLDR only has
>>>>>> one set of formatting data. From formatting aspect, the difference in
>>>>>> date
>>>>>> calculation between them is not important. Our current plan is:
>>>>>>
>>>>>> 1. Add a new extension "cv" (calendar algorithm variant - tentative).
>>>>>> 2. Investigate necessary types from experts, based on some references
>>>>>> including your ticket above.
>>>>>> 3. Deprecate "islamicc", and map to ca-islamic-cv-??? (??? will be
>>>>>> determined later).
>>>>>>
>>>>>> Note that the type value is limited to 8 characters because of BCP 47
>>>>>> definition. We also considered multi-segment calendar type like
>>>>>> islamic-umalqura as you suggested in the ticket, but it will require a
>>>>>> bunch of duplicated references in CLDR data formatting data. For this
>>>>>> reason, we are in favor of separating minor algorithm differences in a
>>>>>> separate extension.
>>>>> FWIW, I like the "cv" variant concept as it makes logical sense. It
>>>>> will be harder to integrate into JSR-310 (where our methods take a
>>>>> single String). The lookup from a Locale object will of course pose no
>>>>> problem to adapt.
>>>>>
>>>>> Stephen