Re: [idn] call for comments for REORDERING<024301c149a0$c65b1ee0$ec1bd9d2@temp><4.2.0.58.J.20011010135529.03d9e6a0@localhost><024b01c15847$11e8b430$0501000a@jamessonyvaio><4.2.0.58.J.20011019152610.037f1100@localhost>

[Martin Duerst <duerst@w3.org>]

At 17:48 01/10/19 +0900, Soobok Lee wrote:

>----- Original Message -----
>From: "Martin Duerst" <duerst@w3.org>
>  >
> > >Current IDNA/nameprep does not prohibit, but discourage including
> > >unassigned code points in legal IDN labels, because new 
> normalization/case
> > >mappings
> > >would be defined on them in the future. some ACE labels including 
> unsigned
> > >code block (tagalog?) might be proven invalid in the future. 
> Nameprep/NFKC
> > >Versioning tag schems using new ACE prefix will be needed in the 
> future, i
> > >guess.

Actually, because we do on purpose not prohibit unassigned codepoints
on the client side, it is completely impossible to introduce reordering
for any script that is added later.

The idea behind this is that if e.g. Tagalog gets added to
Unicode, and the IETF decides to add it to the allowed set
of characters for domain names, then the registries that
want to accept Tagalog have to update their software
immediately (no big deal for them), but deployed software
can use Tagalog without having to change nameprep/ACE
(unless they use characters which have to be normalized,
which may happen but will be rare). So existing clients
will already ACE the Tagalog codepoints without reordering,
and if we introduce reordering for Tagalog, there will
be a mess.


Regards,   Martin.