Nameprep and NFKC

John C Klensin klensin at
Sat Oct 16 16:03:32 CEST 2010

--On Saturday, October 16, 2010 12:55 +0300 "Abdulrahman I.
ALGhadir" <aghadir at> wrote:

> So basically is that a flaw on the idna2008 demo or is it
> common behavior of the IDNA2008 or is it normalization problem
> (NFC) ? 

Vint's answer is the correct one -- it is deliberate behavior of
IDNA2008 and incorrect input into the demo.  I tried to say that
in an earlier note.   I do think that it would be useful to
alter the demo so that it makes a test for the input strings
being in NFC form (as required in Sections 4.1 and 5.2 of RFC
5891) and generates a clear error message if the test fails
rather than continuing to process the string.  I think that is
more a matter of taste rather than a "flaw" in the demo, but
your experience suggests to me that the demo would be more
useful if these strings were rejected with an explanation.


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