[loc-en-dev] Comments to the draft spec

[Yoshito Umaoka]

Sato-san, I added my comments below -

> If it's BCP47, "ja_JP_JP" or "no_NO_NY" is illegal because the variant 
> subtag cannot be two-letter code.  I think limiting builder strictly to 
> BCP47 is OK because developers can always use the old constructors.

I got your point.  Yes, ja-JP-JP is illegal unless variant JP is 
registered in IANA registry.  It could be mapped to ja-JP-x-JP if my 
understanding is correct.

I do not like to invalidate existing Java Locales just for this reason. 
  There are two possible solutions here -

1. Register these Java's proprietary enhancement to the IANA registry.
2. Do not apply strict validation when a Locale is created, but handle 
it when converting to BCP47 language tag.

> 
> Does LDML define the mappings between, say "-k-collatio-traditio" and 
> "@collation=traditional"?  If it's clearly defined in the LDML, we can 
> just say, Locale class implements -k extension as LDML's keywords.
> 

It's defined in the latest LDML spec.  CLDR team actually should 
register letter "k" for the purpose in the language tag registry, which 
is not yet done.  We had already agreed to register "k" to the language 
tag registry.

I actually raised an issue about the truncation and we'll discuss this 
in the CLDR meeting tomorrow.  The problem is that an LDML keyword can 
be systematically mapped to BCP47 extension, but you need full keyword 
name /value list for the inverse mapping.  For example, 
"-k-collatio-traditio" is mapped to "collation=traditonal" in LDML, but 
you need to know "collatio" is the truncated form of LDML "collation", 
"traditio" is the truncated from of LDML keyword value "traditional".

> The reason is, again BCP47 conformance.  If I understand it correctly, 
> language subtag is mandatory in BCP47.

I think so too.  But, as I mentioned, language "und" is valid in BCP47. 
  So empty language code in a Locale can be interpreted as "und" in 
BCP47 language tag.

-Yoshito