[UA-discuss] Mixing between RTL and LTR scripts

[Andrew Sullivan]

On Thu, May 10, 2018 at 10:44:18AM +0000, Don Hollander wrote:
> 
> I’m not sure where this should be documented.   In the Unicode Consortium?   I
> don’t think the IETF, but I may be wrong.  Does it fit within the W3C?

It doesn't fit in any of these.

The IDNA RFCs already say that you need to be careful about this, but
they note, quite correctly, that there is literally no way to make a
rule about entire domain names (as we have noted in this thread too).
It would be possible to publish an RFC, if people really wanted to,
restating that advice more strongly.  But it's still at best going to
be advice.  And unfortunately, some domain names (ones that happen
probably not to be aimed at humans) are _guaranteed_ to have bidi
problems across the whole name in U-label form, because SRV and such
like labels are going to have ASCII components because of the
identifiers of protocols (like _tcp).

> Would it be useful if the UASG published a Good Practice guide to BiDi in
> Domain Names and Email Addresses?   (I think, Raed, that you’ve done the work) 
> We could then update our existing documents to reference it.   Or, if there’s
> someone else who’s got a good guide, we could reference that instead of
> building it afresh.
> 

I think that would be a fine thing to do, but I think that you
probably need someone with serious depth in the DNS and email
protocols to help with it in order to make sure it doesn't run afoul
of the details of the protocols.

Best regards,

A

-- 
Andrew Sullivan
ajs at anvilwalrusden.com