simon at josefsson.org
Tue Apr 26 22:28:49 CEST 2011
"Jiankang Yao" <yaojk at cnnic.cn> writes:
> Dear colleagues,
> This message starts a two-week WGLC on the draft
I support publication of a document to clarify IDNA2008's relationship
to Unicode 6.0 but I believe the content of the above document causes an
instability for U+19DA which can be avoided. From my implementer's
point of view, it seems better to add U+19DA as PVALID in the
BackwardCompatible (G) category so that we have the property that
IDNA2008-Unicode5.2(X) = IDNA2008-Unicode6.0(X) for all strings X that
were permitted by IDNA2008-Unicode5.2.
The above document effectively forbids some strings that were permitted
before. I believe this causes a perception of instability in the
algorithm. It seems that permitting strings with this code point would
not cause any problem in practice. To me that is a strong argument that
good algorithmical/implementation properties are more important than any
consideration for this particular code point. If U+19DA would cause
operational difficulties, I would be more inclined towards forbidding
strings that contains it, but I haven't seen those arguments.
This has been brought up before by others, and I have merely been
convinced by that discussion. I'm not trying to state this point as
anything original. In particular, here are pointers to where Mark Davis
explains the point:
> Note: This draft is a document that updates an earlier RFC by stating
> nothing is to be updated.
That seems wrong. Technically the document does not claim to update any
earlier RFC according to the document content (there is no 'Updates:'
header). Could you clarify what you mean here? Is the intention that
the document will be marked as Updating any earlier RFC or not?
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