[threeten-dev] Islamic calendar variants need disambiguation

[Stephen Colebourne]

As we've discussed before, there are two parallel IDs. For example
"Coptic" and "coptic", or "Hijrah" and "islamic". The table needs
updating with another column for the chronology ID (essentially an
alias based around the 310 class name). The ID isn't limited to 8
letters, but it is probably easiest and simplest to re-use the cv
string. Thus "Hijrah-sa" would be an alias for islamic-sa" in the
of(String) factory method.

Stephen


On 14 January 2013 21:34, Dan Chiba <dan.chiba at oracle.com> wrote:
> 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