At 17:48 01/10/19 +0900, Soobok Lee wrote: >----- Original Message ----- >From: "Martin Duerst" <[EMAIL PROTECTED]> > > > > >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.
