Subject: Re: [EAI] Unicode's PRI #185 & EAI: should the UBA be revised to

From: Shawn Steele <[email-masked]>
Date: Thu, 14 Jul 2011 21:38:04 +0000

> It's not an important point. I guess email addresses are just so deceptively simple.
> In RTL, [email-masked] (where uppercase Latin letters
> stand for RTL characters) is displayed as

> [email-masked]

But mailto:[email-masked] is an IRI, so it should be covered by the document being discussed, and the solutions being discussed avoid that aspect of the problem.

W/o the mailto: it's not really an IRI, though the same solution could be applied.

-Shawn

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From: "Charles Lindsey" <[email-masked]>
Date: Fri, 15 Jul 2011 17:09:49 +0100

On Thu, 14 Jul 2011 22:38:04 +0100, Shawn Steele  
<[email-masked]> wrote:

> But mailto:[email-masked] is an IRI, so it  
> should be covered by the document being discussed, and the solutions  
> being discussed avoid that aspect of the problem.
>

I think that is the clue to the matter. Whatever happens to IRI ordering  
and (perhaps separately) to email-address ordering, there should be an  
invariance rule which states that whatever exists to the right of any  
"mailto:" should always be a valid email-address (obviously, ignoring any  
fancy flags at the end of the mailto for setting subjects, etc).

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131                       
   Web: http://www.cs.man.ac.uk/~chl
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---

From: John C Klensin <[email-masked]>
Date: Fri, 15 Jul 2011 13:05:34 -0400

--On Friday, July 15, 2011 17:09 +0100 Charles Lindsey
<[email-masked]> wrote:

>> But mailto:[email-masked] is an
>> IRI, so it   should be covered by the document being
>> discussed, and the solutions   being discussed avoid that
>> aspect of the problem.
>> 
> I think that is the clue to the matter. Whatever happens to
> IRI ordering and (perhaps separately) to email-address
> ordering, there should be an invariance rule which states that
> whatever exists to the right of any "mailto:" should always be
> a valid email-address (obviously, ignoring any fancy flags at
> the end of the mailto for setting subjects, etc).

Charles (and others),

There is one way to make this really simple and globally
consistent and that is to treat the "@" (for email addresses)
and "." label separator for domain names as absolute delimiters.
That makes
    [email-masked] 
display is as either
   [email-masked]   or
   [email-masked]
but is the end of the high-risk cases.

Unfortunately, it also prohibits any sort of localized display
decisions.  That might be a fine idea for those of us who use
Latin script in a predictable way, but it just won't happen in
some local contexts: if we (or Unicode) say something that
sounds culturally inappropriate or severely surprising to users,
it will be ignored by at least some implementers.  Worse, unless
someone managed a clear and 100% accurate way to distinguish
various pieces of protocol from running text (not just clever
heuristics), there will be periodic dramatic failures.
Consider, for example, the use of 
"joe at example-dot-com" to discourage address harvesting.
Whether it is actually good at that or not, it would very
effectively defeat any sort of rendering system that depends on
"@" to identify an email address in order to handle those
addresses in a special way.   In retrospect and in a more
perfect world, the decision to not require special introducer
and terminator characters for URIs and then to get specific code
points assigned by Unicode that were not to be used for anything
else were probably mistakes.  But we are stuck with them.

    john

---

From: "Aharon (Vladimir) Lanin" <[email-masked]>
Date: Sun, 17 Jul 2011 09:13:55 +0300

> But mailto:[email-masked] is an IRI,
> so it should be covered by the document being discussed

Well, actually, I don't think that the specifics proposed in PRI #185
cover all possible IRIs; it's more focused on the IRIs containing a
path. I don't think that the syntax given there covers the mailto: IRI
because of the @. It should be trivial to extend the syntax to cover
email addresses both with and without the mailto:.

> and the solutions being discussed avoid that aspect of the problem.

Not sure what you mean.

> and "." label separator for domain names as absolute delimiters.

Not sure what you mean by absolute delimiters, but the proposal is
indeed, after identifying an IRI, to treat its "field separators"
(e.g. the dots in the domain name, the slash in the path, etc.) as
strongly LTR instead of neutral, and the IRI as a whole as LTR. That
means that the components of the IRI are ordered consistently LTR,
while usual UBA rules are applied withing a component.

> but is the end of the high-risk cases.

It's the latter. GEORGE is always disdplayed as EGROEG.

> decisions.

Although it is not the preferred option, the proposal also discusses
the possibility of sometimes ordering IRI components RTL. The two
possibilities mentioned are either to make the IRI come out RTL when
it is in an RTL context, or to make it come out RTL when it contains
RTL characters, regardless of context. They want feedback on whether
people would want that, despite the problems. Please see there.

> unless someone managed a clear and 100% accurate way to distinguish

There is no way to achieve 100%, and PRI #185 acknowledges that and
does not strive for 100%.

On Fri, Jul 15, 2011 at 8:05 PM, John C Klensin <[email-masked]> wrote:
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