Comments on IDNA Bidi

Michel Suignard michelsu at
Thu Jan 17 00:26:51 CET 2008

> On Behalf Of Harald Alvestrand
> Michel, you're backing down on the criterion you yourself argued
> strongly for a few messages back. Please decide one way or another.
>- EITHER labels breaking apart on display under certain conditions
>  is unacceptable
>- OR labels breaking apart on display under certain conditions is
> acceptable.
Harald, I think I am with you on reaching for the first way. Breaking labels on display is always a bad idea. However avoiding it completely was not a stated goal of either IDN2003 or IRI (afaik). So on that aspect we don't have a clean precedent. And obviously if you don't have to display (some cases in IRN), we don't really care.

Coming back strictly to IDN, we should achieve it by a mix of repertoire restrictions and additional rules. Your example using CS EN AN CS R in LTR context convinced me that we should probably look into new rules for EN and AN types. The issues with ET and ON types should probably be dealt with by eliminating most of them by repertoire restrictions.

Where I may differ from you is that I am not completely convinced we can achieve 100% success in avoiding labels breaking apart in the most extreme pathological cases. But you have convinced me that it is worth a look at improving the rules further for some bidi types such as EN and AN.

Best regards,


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