Mark Davis ☕
mark at macchiato.com
Thu Jan 27 23:20:17 CET 2011
2011/1/27 John C Klensin <klensin at jck.com>
> --On Thursday, January 27, 2011 08:56 -0800 Mark Davis ☕
> <mark at macchiato.com> wrote:
> > Mark
> >> > The B lines are valid for both T and N, so you should
> >> > include them.
> >> Then I'm stuck, and I would appreciate clarification from
> >> everyone about what IDNA2008 is saying. Your second test
> >> case is:
> >> B; FASS.DE; fass.de; ;
> >> The only place (that I can find) where IDNA2008 converts to
> >> lower case is in the following paragraph:
> > Sorry I wasn't not clear; The second column is the "Source",
> > which you need to ignore since you are not mapping.
> > Let's take a couple of lines:
> > N; Faß.de; faß.de <http://fass.de> <http://fass.de>;
> > You would only look at the 3rd and 4th columns for testing, so
> > faß.de <http://fass.de><http://fass.de>
> > and xn--fa-hia.de.
> Mark, as a suggestion for both the tool and the web page, it may
> be worth noting that, while mapping (or one flavor or another)
> is optional with IDNA2008, the one restriction is that one must
> not map a PVALID character to something else. Whatever the
> advantages of doing so --for transition reasons, personal
> preferences, or otherwise-- a program or system that remaps one
> PVALID character into one or more others is not in conformance
> with the intent of the IDNA2008 standards.
Yes, I agree.
The only 4 characters that have such a mapping are for the transitional
(migration) from IDNA2003. It should be clear from the text that such a
mapping isn't fully conformant to IDNA2008; if it needs further
clarification, let me know.
In adding instructions for IDNA2008 testing, we'll make it clear that the T
lines should be skipped for fully IDNA2008 conformant implementations.
> > The other take-away I have from this is that we need to have
> > clearer instructions for those who want to use the file, and
> > that do not support mapping. I'll add that to a list of
> > feedback for the committee.
> >> However "FASS.DE" is not an A-label.
> >> Is there anything else in IDNA2008 that lower case labels?
> There is nothing at all in IDNA2008 that lower-cases labels,
> much less applying the Unicode case folding operation (which is
> quite controversial, especially as a character-replacement
> mapping algorithm).
> >> Further, I don't interpret the above to cause case conversion
> >> of the string looked up in DNS. I only interprete it as
> >> converting it to lower case for the purpose of comparing with
> >> the output from the Punycode output. It would be nice if
> >> someone could confirm or reject this interpretation as well.
> That interpretation is correct. Note also that conversion of
> "ß" (U+00DF/ Sharp S/ Eszett) to "ss" is not a lower case
> conversion operation (because U+00DF is already lower case. It
> results from a case-folding operation instead.
> best regards,
> Idna-update mailing list
> Idna-update at alvestrand.no
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