Re: [idn] IDNs in email message bodies

[John C Klensin <klensin@jck.com>]

--On Monday, 26 March, 2001 06:03 +0000 "Adam M. Costello"
<amc@cs.berkeley.edu> wrote:

> John C Klensin <klensin@jck.com> wrote:
> 
>> My recipient now has your address in ACE form in a message
>> body... ...she translates my message into Arabic or Chinese
>> and then sends it... ...translation performed by an automatic
>> translator that has not been "taught" to detect ACE strings
>> in running text...
>> 
>>...
> How is this an ACE issue?  Wouldn't the problem be exactly the
> same for a regular ASCII domain name?

Just about, but not quite.  As long as all domain names (and
email address local parts) are [restricted-]ASCII, one does not
have the problem of figuring out whether a name one is looking
at is the intended name or an encoding of some other name.  And
that problem gets especially interesting when the encoding is of
a name in a script that matches the script (but not necessarily
the encoding) of a body part in which it might be embedded.

And there are law of least astonishment UI issues here.  If the
email address (local and domain parts) is, e.g., encoded in ACE
from Arabic, and a message body ends up being sent in Arabic
text, I would predict a good deal of user irritation if the
email address appeared in that running text in ASCII (with the
added irritations of embedding left-to-right text in a
right-to-left script stream) because it was pasted from a
"from:" field rather than being keyed in.

This also implies some other UI issues for which "display only"
(as suggested by Patrik's notes and others) is not sufficient.
If a message comes in for which the originating and target
addresses are encoded from the normal script of my operating
environment, I will probably expect them to be displayed into
that script.  But, if the character encodings of the operating
system are different from what shows up on the wire and/or if
the operating system's "clipboard" or equivalent are modularized
in certain ways, if I paste something out of the display that
has been rendered into native script, I'm probably going to get
the native script in my text, not the ACE form.  If that isn't
what is wanted,...

    john