<font face="georgia,serif">The RFC is written to be version-neutral. I think it was just a mistake that it refers to a specific version of the file.</font><div><font face="georgia,serif"><br></font></div><div><font face="georgia,serif">The data in the UCD establish the exact definition of the different properties, subject to the stability policies on <a href="http://unicode.org/policies/stability_policy.html">http://unicode.org/policies/stability_policy.html</a>. That is, the derivation of the property is not normative; the data is.</font></div>
<div><font face="georgia,serif"><br></font></div><div><font face="georgia,serif">See also Section 2.1 in <a href="http://www.unicode.org/reports/tr44/#Simple_Derived">http://www.unicode.org/reports/tr44/#Simple_Derived</a>. In particular:</font></div>
<blockquote class="webkit-indent-blockquote" style="margin: 0 0 0 40px; border: none; padding: 0px;"><div><font face="georgia,serif"><span class="Apple-style-span" style="font-family: Arial, 'Lucida Sans Unicode', 'Arial Unicode MS', sans-serif; "><p>
Implementations should simply use the derived properties, and should not try to rederive them from lists of simple properties and collections of rules, because of the chances for error and divergence when doing so.</p></span></font></div>
<div><font face="georgia,serif"><span class="Apple-style-span" style="font-family: Arial, 'Lucida Sans Unicode', 'Arial Unicode MS', sans-serif; "><p>Definitions of property derivations are provided for information only, typically in comment fields in the data files. Such definitions may be refactored, refined, or corrected over time.</p>
</span></font></div></blockquote><div><font face="georgia, serif">Mark<br><br><i>— Il meglio è l’inimico del bene —</i></font><br>
<br><br><div class="gmail_quote">On Tue, Mar 22, 2011 at 08:57, Simon Josefsson <span dir="ltr"><<a href="mailto:simon@josefsson.org">simon@josefsson.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">Mark Davis ☕ <<a href="mailto:mark@macchiato.com">mark@macchiato.com</a>> writes:<br>
<br>
> In <a href="http://unicode.org/Public/5.2.0/ucd/DerivedCoreProperties.txt" target="_blank">http://unicode.org/Public/5.2.0/ucd/DerivedCoreProperties.txt</a><br>
><br>
> <<a href="http://unicode.org/Public/5.2.0/ucd/DerivedCoreProperties.txt" target="_blank">http://unicode.org/Public/5.2.0/ucd/DerivedCoreProperties.txt</a>>Search in<br>
> page for "Default_I" to find it.<br>
<br>
</div>Thanks -- I was expecting the text at the top...<br>
<br>
The file says:<br>
<br>
# Derived Property: Default_Ignorable_Code_Point<br>
# Generated from<br>
# Other_Default_Ignorable_Code_Point<br>
<div class="im"># + Cf (Format characters)<br>
# + Variation_Selector<br>
# - White_Space<br>
# - FFF9..FFFB (Annotation Characters)<br>
# - 0600..0603, 06DD, 070F (exceptional Cf characters that should be visible)<br>
<br>
</div>00AD ; Default_Ignorable_Code_Point # Cf SOFT HYPHEN<br>
034F ; Default_Ignorable_Code_Point # Mn COMBINING GRAPHEME JOINER<br>
...<br>
<br>
I'm not sure how to interpret this.<br>
<br>
Is the meaning of Default_Ignorable_Code_Point in RFC 5892:<br>
<br>
1) The actual list of code points, which is Unicode version specific,<br>
with the Default_Ignorable_Code_Point flag?<br>
<br>
2) All code points that fulfills these critera, for all future Unicode<br>
versions:<br>
<div class="im"><br>
Other_Default_Ignorable_Code_Point<br>
+ Cf (Format characters)<br>
+ Variation_Selector<br>
- White_Space<br>
- FFF9..FFFB (Annotation Characters)<br>
- 0600..0603, 06DD, 070F (exceptional Cf characters that should be visible)<br>
<br>
</div>3) Whatever Default_Ignorable_Code_Point is defined to be in whatever<br>
Unicode version is the recent.<br>
<br>
I am guessing 2) because the reference in RFC 5892 is explicitly to a<br>
versioned Unicode data file rather than to TR44.<br>
<br>
(Note that the definitions are slightly different in 5.2.0 and 6.0.0.)<br>
<div><div></div><div class="h5"><br>
/Simon<br>
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</div></div></blockquote></div><br></div>