Re: [idn] call for comments for REORDERING

["Soobok Lee" <lsb@postel.co.kr>]

----- Original Message ----- 
From: "Martin Duerst" <duerst@w3.org>
To: "Soobok Lee" <lsb@postel.co.kr>; "James Seng/Personal" <jseng@pobox.org.sg>; <idn@ops.ietf.org>
Sent: Friday, October 19, 2001 6:23 PM
Subject: Re: [idn] call for comments for REORDERING


> 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,

maybe problematic and unsafe. 
What if future NFC/NFKC maps them into other code points ?
There will be a mess, too.

> and if we introduce reordering for Tagalog, there will
> be a mess.

Current REORDERING does nothing with TAGALOG and adds
no new problem into ACE. the problem is alerady inherent
in ACE and nameprep version scheme, and is not due to
REORDERING.

Prefix-based version scheme will solve those problems.

Soobok Lee






> 
> 
> Regards,   Martin.
>