There is already a draft mapping on <a href="http://unicode.org/reports/tr46/">http://unicode.org/reports/tr46/</a> - feedback is welcome.<br><br clear="all">Mark<br>
<br><br><div class="gmail_quote">On Mon, Mar 2, 2009 at 22:28, Adam M. Costello <span dir="ltr"><idna-update.amc+0+@nicemice.net.removethisword></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="im">Harald Alvestrand <<a href="mailto:harald@alvestrand.no">harald@alvestrand.no</a>> wrote:<br>
<br>
> do you think that the canonicalization function you're positing can be<br>
> described in an Unicode-version-independent way?<br>
<br>
</div>I think it can, but I'll need help from our resident Unicode experts to<br>
provide the definition.<br>
<br>
The Unicode standard promises normalization stability from<br>
version 4.1 onward, and case-folding stability from version<br>
5.0 onward. Section 3.13 of version 5.0 suggests this for<br>
compatibility-normalize-and-case-fold:<br>
<br>
NFKD(toCasefold(NFKD(toCasefold(NFD(X))))) =<br>
<br>
I don't know why so many iterations are needed, and I don't know why the<br>
first step is NFD rather than NFKD.<br>
<br>
We would of course want to change the last NFKD (or both of them) to<br>
NFKC.<br>
<br>
After applying this function, we would then check the result for<br>
disallowed code points and other violations (described in the existing<br>
drafts), and either return it or return an error.<br>
<br>
We'd have to consider & specify what to do about the handful of obscure<br>
incompatibilites between Unicode 3.2 and 5.0, but we should never have<br>
to do that again because of the newer Unicode stability policies.<br>
<br>
Unicode experts, please comment on the feasibility of this approach, and<br>
suggest ways to simplify it if you can think of any.<br>
<br>
Thanks,<br>
<font color="#888888">AMC<br>
</font><div><div><span id="q_11fcb171e6fc2c2e_3" class="h4">- Show quoted text -</span></div><div class="h5">_______________________________________________<br>
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