<span class="Apple-style-span" style="font-family: Garamond; "><div style="margin-top: 0px; margin-bottom: 0px; ">I had a chance to review the documents again. There is good progress; the split of the definitions is very helpful. There is a tendency to always look for the remaining issues in the document, so I want to thank John for all the work done on this. I'll respond with some comments, with different subjects for easier tracking.</div>
<div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-size: 16px; font-weight: bold; ">Definitional Problem with U-Label and A-Label</span></div>
<div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; ">I believe (although am not 100% sure) that the intent is for both U-Label and A-Label to only refer to *valid* possible labels under the specifications of IDNA2008, but the text does not yet support that consistently. Here is the breakdown. (I'm using D1.3 to mean section 1.3 in Defs, and so on, with P for protocol, B for bidi, R for rationale).</div>
<div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-weight: bold; ">LDH</span></div><div style="margin-top: 0px; margin-bottom: 0px; ">
The following conditions:</div><div style="margin-top: 0px; margin-bottom: 0px; "><ol style="margin-top: 0px; margin-bottom: 0px; "><li style="margin-top: 0px; margin-bottom: 0px; ">Must match <a id="gop9" href="http://tools.ietf.org/html/rfc952" title="http://tools.ietf.org/html/rfc952" style="color: rgb(85, 26, 139); ">http://tools.ietf.org/html/rfc952</a> </li>
<ul style="margin-top: 0px; margin-bottom: 0px; "><li style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-family: -webkit-monospace; white-space: pre; "><name> ::= <let>[*[<let-or-digit-or-hyphen>]<let-or-digit>]</span></li>
</ul><li style="margin-top: 0px; margin-bottom: 0px; ">Length limited to 1..63 (<a id="m4cb" href="http://tools.ietf.org/html/rfc1034" title="http://tools.ietf.org/html/rfc1034" style="color: rgb(85, 26, 139); ">http://tools.ietf.org/html/rfc1034</a>, 3.1)</li>
<li style="margin-top: 0px; margin-bottom: 0px; ">Must not have hyphens in both positions 3 and 4. (new condition)</li></ol><div style="margin-top: 0px; margin-bottom: 0px; "><br></div></div><div style="margin-top: 0px; margin-bottom: 0px; ">
Condition 3 is not stated in D2.3.1.2, but appears elsewhere. Should be in Defs <a href="http://2.3.1.2">2.3.1.2</a>.</div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; ">
<span class="Apple-style-span" style="font-weight: bold; ">A-Label </span></div><div style="margin-top: 0px; margin-bottom: 0px; ">I believe the definition should be the following conditions:</div><div style="margin-top: 0px; margin-bottom: 0px; ">
<ol style="margin-top: 0px; margin-bottom: 0px; "><li style="margin-top: 0px; margin-bottom: 0px; ">ASCII string of length 5 to 64</li><li style="margin-top: 0px; margin-bottom: 0px; ">starts with "xn--" (or case variants thereof) [implicitly no hyphen at end]</li>
<li style="margin-top: 0px; margin-bottom: 0px; ">the remainder is valid punycode</li><li style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-style: italic; ">and</span> the depunycoded result must be a valid U-Label</li>
</ol><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; ">I believe that the above is the intended definition, but it is not fully supported by the text in Defs, except (perhaps) very indirectly. Note that A-Label according to this is dependent on U-Label. To make sure that we are not circular, we need to define U-Label independently of A-Label.</div>
<div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-weight: bold; ">Putative A-Label</span></div><div style="margin-top: 0px; margin-bottom: 0px; ">
Any string that is all ASCII, but is neither LDH or A-Label.</div></div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-weight: bold; ">U-Label</span></div>
<div style="margin-top: 0px; margin-bottom: 0px; ">This is difficult to make out. I believe the definition should be:</div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; ">
<ol style="margin-top: 0px; margin-bottom: 0px; "><li style="margin-top: 0px; margin-bottom: 0px; ">contains at least one non-ASCII character.</li><li style="margin-top: 0px; margin-bottom: 0px; ">is in form NFC (P4.2)</li>
<li style="margin-top: 0px; margin-bottom: 0px; ">contains neither DISALLOWED nor UNASSIGNED (P4.3.1)</li><li style="margin-top: 0px; margin-bottom: 0px; ">no hyphens in both position 3 and 4 (P4.3.2.1) [implicitly no hyphen at start or end]</li>
<li style="margin-top: 0px; margin-bottom: 0px; ">no leading combining marks (P4.3.2.2)</li><li style="margin-top: 0px; margin-bottom: 0px; ">obeys context constrains (P4.3.2.3)</li><li style="margin-top: 0px; margin-bottom: 0px; ">
obeys bidi constraints (P4.3.2.4)</li><li style="margin-top: 0px; margin-bottom: 0px; ">converts to valid punycode of length < 60</li></ol><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><span class="Apple-style-span" style="font-style: italic; ">Protocol: </span></div>
<div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; ">4.3.3 says the following:</div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><span class="Apple-style-span" style="font-family: Times; font-size: 16px; "><pre class="newpage" style="margin-top: 0px; margin-bottom: 0px; page-break-before: always; ">
<span class="Apple-style-span" style="font-size: 12px; "><span class="Apple-style-span" style="font-size: 13px; "> </span>Strings that have been produced by the steps above, and whose </span></pre></span><div style="margin-top: 0px; margin-bottom: 0px; ">
<span class="Apple-style-span" style="font-family: -webkit-monospace; white-space: pre; "> contents pass the above tests, are U-labels.</span></div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; ">
However, this may does not include condition 8 above; that is the test for mapping to A-Label (eg overly long punycode) in 4.5, not "above" <a href="http://4.3.3.">4.3.3.</a> Condition #1 is also implicit.</div>
<div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-style: italic; ">Defs: </span></div><div style="margin-top: 0px; margin-bottom: 0px; ">
<span class="Apple-style-span" style="font-style: italic; "><br></span></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-style: italic; "><span class="Apple-style-span" style="font-style: normal; "><a href="http://2.3.1.1">2.3.1.1</a> says the following:</span><br>
</span><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-family: Times; font-size: 16px; "><pre class="newpage" style="margin-top: 0px; margin-bottom: 0px; page-break-before: always; ">
<span class="Apple-style-span" style="font-size: 12px; "> A "U-label" is an IDNA-valid string of Unicode characters,
including at least one non-ASCII character, expressed in a
standard Unicode Encoding Form -- in an Internet transmission
context this will normally be UTF-8 -- and subject to the
constraint below.</span></pre></span></div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><ol style="margin-top: 0px; margin-bottom: 0px; "><li style="margin-top: 0px; margin-bottom: 0px; ">This is inconsistent with 4.3.3, with the only constraints being that U-Labels be NFC, be convertable to and from valid A-Labels, and not be of the form xx--.. But the phrase in bullet 2 seems to state that they must meet "all of the requirements of *these specifications*". But it is not clear what those are: they should be listed precisely.</li>
</ol><div><br></div><div>I can understand not wanting to complicate Defs by having conditions 1-8 spelled out completely. It would be possible to handle this without complicating Defs, *if* the specific sections corresponding to the conditions were explicitly referenced in Defs.</div>
<div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; "><span class="Apple-style-span" style="font-weight: bold; ">Putative U-Label</span></div><div style="margin-top: 0px; margin-bottom: 0px; ">
Any Unicode string that contains at least one non-ASCII character, but is not a U-Label.</div><div style="margin-top: 0px; margin-bottom: 0px; "><br></div><div style="margin-top: 0px; margin-bottom: 0px; ">I can suggest some text fixes, if that would be helpful, but wanted to get the principles right first.</div>
<div><br></div></div></span>Mark<br>