Standardizing on IDNA 2003 in the URL Standard

Andrew Sullivan ajs at anvilwalrusden.com
Wed Jan 15 18:19:26 CET 2014


On Wed, Jan 15, 2014 at 04:26:22PM +0000, Anne van Kesteren wrote:

> I have not checked what of that can be removed if we use UTS #46
> instead. Certainly referencing IDNA2008 directly does not work, as
> "A.com" does not become "a.com", which would presumably break too many
> scripts.

IDNA2008 has no effect at all on "A.com" or "a.com".

IDNA2008 does say that "Aà.com" is not PVALID.  I _believe_ that under
IDNA2003 that becomes "aà.com".  The reason IDNA2008 doesn't do that
is because you can't tell whether "Aà.com" is supposed to be "àà.com"
or "aà.com", so IDNA2008 tries to say "don't do that".

IDNA2008 also says that you can do some local mapping.  In my opinion,
UTS #46 goes too far with compatibility attempts to IDNA2003, but I'm
prepared to accept that lots of other people disagree.

A

-- 
Andrew Sullivan
ajs at anvilwalrusden.com


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