Special case for Bidi in draft-ietf-idnabis-protocol-14

Harald Alvestrand harald at alvestrand.no
Tue Sep 8 21:47:26 CEST 2009

Andrew Sullivan wrote:
> On Mon, Sep 07, 2009 at 06:49:55PM +0900, "Martin J. Dürst" wrote:
>> I agree with Mati. I think in protocol, checking the BIDI constraints 
>> should just be a MUST. BIDI then can say (as it already does) that these 
>> constraints are essentially irrelevant for LTR-only domain names.
> I can think of a case where not checking BIDI rules would be
> justified.  Suppose a system is configured such that it is impossible
> to enter RTL characters, and there are no fonts for displaying RTL
> characters either.  In this case, actually performing the BIDI check
> would just be a waste of cycles: they're effectively impossible
> anyway.  (The purpose of the BIDI rule, after all, derives primarily
> from the display characteristics of RTL versus LTR.  Therefore, if no
> RTL is possibly displayed, then there are no display characteristics.)
On such a system, you can still click on hyperlinks that contain domain 
names with RTL characters in them. The fact that the user doesn't see 
them doesn't mean he can't use them.

(they would probably show up as little square boxes in the status bar 
when hovering over the link. Not many people would notice.)

That said, I'm happy with the "minimize changes after Last Call" 
approach and sticking with the present SHOULD.
> Such a clear exception justifies a SHOULD, I think.  I am, however,
> not wedded to this position.
> A

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