[UA-discuss] Mixing between RTL and LTR scripts

[Andrew Sullivan]

On Sat, May 05, 2018 at 12:03:37PM +0000, Abdalmonem Tharwat Galila wrote:
> So how could any application process the domain name !! It will be RTL or LTR
> !!
> Ex Abdo.عبدو.Ahmed 
> Where is the 1st label !!! Is it Abdo or Ahmed !!!

Yep.  It's extremly difficult.  "Don't do that," is the general
advice, but there's no way in the protocol to prevent it.

Remember, every one of those dots in that domain name represents a
possible new locus of control (because there could be a delegation
there).  You can't make policies about the whole domain name system.
That's a feature of the DNS, and not something that is likely to
change.

> Consider if the domain name starts with RTL text !! Or RTL in the middle !!! Or
> at the end !!!

There actually is _some_ discussion of this in the BIDI RFC
(https://tools.ietf.org/html/rfc5893).  But IDNA is defined for
labels, not domain names, because of the way the DNS works.

Best regards,

A

-- 
Andrew Sullivan
ajs at anvilwalrusden.com