Comments on IDNA Bidi

Harald Alvestrand harald at
Wed Jan 16 20:04:40 CET 2008

Michel Suignard skrev:
> Harald, what you call 'break badly' or 'break apart' is what I perceive as a logical order bidi string being rendered or printed in a visual order which maybe close to impossible to decipher for the mere mortals. Unfortunately that is a common occurrence in bidirectional processing and for example the case of 'part numbers' (in essence a mix of random letters, digits and possibly some symbols) has been frequently used to show how the situation can become quickly hopelessly complicated. At the same time, bidi readers are much more skilled at reading complex bidi strings than we are.
> Domain name and by extension IRI are almost as bad as part numbers with the added hindrance that bidi format override can't typically be used.
> I don't think that anybody expected at the time of IDNA2003 that with the bidi rules, all domain names using bidi rules would display with an easy to decipher text. Some could be harder than others. In other words, in my opinion 'breakage' is not an objective description of what happens. If a reader used to bidi text can read what someone else would qualified as 'broken' it is in fact acceptable.
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
- OR labels breaking apart on display under certain conditions is

Don't waffle. State one of the two.

If you go for the first option, I'll give you free latitude to define
what conditions it's unacceptable for (we've already dropped "next to
RLO/PDF pairs" from consideration), as long as you give me a rule that
can be written into a test script for when those conditions apply.

If you go for the second opinion, and this is supported by a large
section of the community, I will write into the document that "based on
the advice of Michel Suignard, we have concluded that it is not possible
to give any guarantee about labels staying together, and therefore, we
are not making any attempt to make rules that bar you from registering
labels that break apart when displayed. Let the user beware."


More information about the Idna-update mailing list