The Two Lookups Approach (was Re: Parsing the issuesand finding a middle ground -- another attempt)

Martin Duerst duerst at
Sat Mar 7 07:52:48 CET 2009

At 01:41 09/03/07, John C Klensin wrote:

>It is worth stressing that the occurrence of this sort of
>problem does not depend on IDNA2008.  Paul's IDNAv2 proposal
>would cause it equally well, as would anything else that
>provides a change from Unicode 3.2 to Unicode 5.1 and, more
>generally, most or all future changes to Unicode that add new
>characters to existing scripts to improve the way in which those
>scripts can be expressed.

To be precise, only characters that interact with others
in the script would be problematic, not completely independent
characters. Or are I'm missing something?

>>From my perspective, "lookup once following IDNA2008 rules and
>fall over to an IDNA2003 lookup if nothing is found" stinks less
>than "two lookups always", partially for the reasons you
>identified.  I don't especially like it but, again, I think we
>need to search for "least bad", not "wonderful and perfect",
>because I don't think the latter is likely to exist.

I guess I have to agree here.

Regards,    Martin.

#-#-#  Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University
#-#-#       mailto:duerst at     

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