draft-liman-tld-names-00.txt and bidi

Andrew Sullivan ajs at shinkuro.com
Sun Mar 8 16:53:57 CET 2009

On Sat, Mar 07, 2009 at 03:43:02PM +0900, Martin Duerst wrote:
> You are right that there is a bidi issue. For some very specific
> example, please see Example 11 at
> http://www.w3.org/International/iri-edit/BidiExamples
> (please read the legends or tooltips carefully).
> The reason why there are bidi issues is:
> - Non-IDN labels turn up in IDNs
> - Digits get close to RTL characters, maybe only separated by dots
> - In the bidi algorithm, numbers and dots get associated with nearby
>   text and thrown around

Ok.  Now the important question is, is it ever possible for Punycode
to produce output that ends in a digit?  I haven't run into an example
yet, but I haven't been able to convince myself that's anything but an
accident.  If someone who understands the algorithm better than I
says, "No, it can't, and here's why," then we'll be in a position to
add to draft-liman-tld-names a restriction that a TLD must both begin
_and end_ with an ASCII letter, and the problem will automatically go
away.  Otherwise, we can't make that rule.  Right?


Andrew Sullivan
ajs at shinkuro.com
Shinkuro, Inc.

More information about the Idna-update mailing list