2015-05-19 0:50 GMT+02:00 Doug Ewell <d...@ewellic.org>:
> > but fow we just have "i-", deprecated but still valid,
>
> "i-" is not deprecated.
In the IANA database they are all replaced. I call that "deprecated" a bit
abusively, but there's no longer any interest in them.
>> for all other letters there's no parsing defined for now, their syntax
>> is unknown and they are not interchangeable without a standard, so
>> they are used only for private use
> Extension 't' was defined in 2011 and 'u' in 2010. They have
> well-defined syntax, specified in RFC 6497 and 6067 respectively.
You are speaking of extensions subtags after the initial subtag, I did not
discuss them.
I was just speaking about the initial subtag (before the first hyphen),
where "t" and "u" are not defined: only "x" and "i" are defined there ("i"
is not defined in the other singletons for trailing subtags).
> Undefined singletons may not be used for private use.
For private use (meaning NOT for interchanges) NOTHING is forbidden, you
are never bound to any standard. There are lots of places where these
private extensions are used and not discussed.
>> some BCP47 use an empty first subtag, i.e. the tag starts by an
>> hyphen;
> Absolutely, utterly false.
Absolutely, utterly true, but a word was missing in my sentence "some BCP
47 extensions" (which are private, local only to a specific software in its
internal data).
