[UA-discuss] Progress on HTML and email...

[Andrew Sullivan]

On Mon, Nov 13, 2017 at 05:47:20AM +0000, Mark Svancarek via UA-discuss wrote:
> 
> The assumption is that all local parts are ASCII letters-digits and that IDNs in the domain part should be expressed in punycode.  This is of course doubly broken, because humans can’t really use punycode.
> 
> Fixing the local part is a good start and I encourage it.  But if the domain name part continues to prohibit Unicode, it won’t actually help anyone.
> 

The domain part does not actually prohibit Unicode in the strict sense.  There's a note in the document that says

    This syntax allows e-mail addresses with Internationalised Domain
    Names using punycode, such as example at xn--d1acpjx3f.xn--p1ai. A
    user agent should represent that in the user interface as
    example@яндекс.рф

So, the user-agent is asked to do the IDNA transformation from A-label
to U-label for display purposes.  Since under IDNA2008 that ought to
be a 1:1 and fully reversible operation, it shouldn't be a big deal.
It's true that this input restriction won't produce an EAI address,
but that is trivial to fix, also, if you do the IDNA transformation.

Best regards,

A

-- 
Andrew Sullivan
ajs at anvilwalrusden.com