Standardizing on IDNA 2003 in the URL Standard

Andrew Sullivan ajs at
Fri Jan 17 19:49:15 CET 2014

On Fri, Jan 17, 2014 at 07:28:58PM +0100, Patrik Fältström wrote:

> Some people do have the view it is really important mapping is
> uniform across applications, operating systems and cultures. Some do
> think a subset of the mappings must be 1:1. Some think the best
> mappings are done with the help of a locale (that by definition is
> different for different users).
I agree, but an important thing to recognize is that, if you're going
to do this character by character (and I don't know how else to do it
given the semantics of DNS labels), the _only_ thing you can do
reliably is locale-sensitive, and accept that it will frequently
break.  The simple cases are (for instance) the lower case of Latin
decorated vowels, which frequently don't get the decoration in upper
case (mostly for historic typesetting reasons).  And this is not only
true in Latin: Greek has the same problem.  Then there are unusual
mappings, like the Turkish i and dotless-i.

It's not like people decided "oh, case mapping, that's for weenies.
Let's screw with their heads!"  Simultaneous internationalization and
localization turns out to be hard.


Andrew Sullivan
ajs at

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