<div dir="ltr"><div class="gmail_default"><font face="times new roman, serif">The main issue for CLDR and other clients like it is to be able to have completely stable canonical identifiers. The zone.tab doesn't quite work for that, because of changes like Asia/Kolkata. </font><font face="times new roman, serif">As far as CLDR is concerned, the TZIDs are purely internal identifiers, and it makes no difference whether one is spelled <span style="color:rgb(0,0,0)">Calcutta or Kolkata; end users should never ever see those anyway. What is a great concern is maintaining stability of the identifiers, so that they are stable keys for translations and other related usage. </span></font><font face="times new roman, serif">That's why CLDR needs to keep its own list (not really wanting to). These use the zone.tab IDs, but are stabilized (eg, no changes in spelling). </font><font face="times new roman, serif">CLDR also adds </font><span style="font-family:'times new roman',serif">one identifier "Etc/Unknown", which is used in circumstances where a field is required, but there is no valid, known TZID.</span></div>
<div class="gmail_default"><br></div><div class="gmail_default"><div class="gmail_default"><font face="times new roman, serif">Note: I was wrong about the removal of IDs: I was thinking of the removal of Timbuktu in 2006, but that was moved to the backward file. <a href="http://article.gmane.org/gmane.comp.time.tz/866/match=remove+1970">http://article.gmane.org/gmane.comp.time.tz/866/match=remove+1970</a></font></div>
<div class="gmail_default"><font face="times new roman, serif"><br></font></div><div class="gmail_default"><font face="times new roman, serif">===</font></div><div><font face="times new roman, serif"><br></font></div><div class="gmail_default">
<font face="times new roman, serif">Not germane to the above, but FYI: </font></div><div class="gmail_default"><span style="font-family:'times new roman',serif"><br></span></div><div class="gmail_default"><span style="font-family:'times new roman',serif">CLDR also adds BCP47-compatible stable short identifiers. BCP47 has the historical restriction of no more than 8 characters, and only ASCII letters and digits. The short identifiers use UN [LOCODE] 5-letter codes wherever possible. There are a few identifiers of length not equal to 5, used where there is no corresponding LOCODE, such as "usnavajo" for "America/Shiprock Navajo", or "utcw01" for "Etc/GMT+1". Example:</span></div>
<div class="gmail_default"><span style="font-family:'times new roman',serif"><br></span></div><div class="gmail_default"><div class="gmail_default"><font face="times new roman, serif"><type name="inccu" alias="Asia/Calcutta Asia/Kolkata" description="Kolkata, India"/></font></div>
</div></div><div class="gmail_default"><div class="gmail_default"><br></div><div class="gmail_default" style><font face="times new roman, serif">There is one other (minor) issue with the identifiers. The TZDB separates zones by country in zone.tab, but it is missing the following BCP47 regions:</font></div>
<div class="gmail_default" style><font face="times new roman, serif"><br></font></div><div class="gmail_default" style><font face="times new roman, serif"><span style="background-color:rgb(240,238,240);color:rgb(0,0,0)">Ascension Island [AC]</span><br>
</font></div><div class="gmail_default" style><font face="times new roman, serif"><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)">Bouvet Island [BV]</span><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)"><br>
</span></font></div><div class="gmail_default" style><font face="times new roman, serif"><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)">Clipperton Island [CP]</span><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)"><br>
</span></font></div><div class="gmail_default" style><font face="times new roman, serif"><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)">Diego Garcia [DG]</span><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)"><br>
</span></font></div><div class="gmail_default"><font face="times new roman, serif"><span style="background-color:rgb(240,238,240);color:rgb(0,0,0)">Ceuta and Melilla [EA]</span><br></font></div><div class="gmail_default" style>
<font face="times new roman, serif"><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)">Heard Island and McDonald Islands [HM]</span><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)"><br></span></font></div>
<div class="gmail_default"><font face="times new roman, serif"><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)">Canary Islands [IC]</span><br></font></div><div class="gmail_default" style><font face="times new roman, serif"><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)">Tristan da Cunha [TA]</span><span style="color:rgb(0,0,0);background-color:rgb(240,238,240)"><br>
</span></font></div></div>
<div class="gmail_default"><font face="times new roman, serif"><br></font></div><div class="gmail_default"><font face="times new roman, serif">Some of these are simply rocks with no permanent inhabitants, but for testing completeness it is useful to have them.</font></div>
<div class="gmail_extra"><font face="times new roman, serif"><br clear="all"></font><div><font face="'times new roman', serif"><div style="background-color:transparent;margin:0px"><div></div></div><div style="background-color:transparent;margin:0px">
<br></div><div style="background-color:transparent;margin:0px"><a href="https://plus.google.com/114199149796022210033" target="_blank">Mark</a></div><div style="background-color:transparent;margin:0px"><i><br></i></div><div style="background-color:transparent;margin:0px">
<i>— Il meglio è l’inimico del bene —</i></div></font><div><div><font face="'times new roman', serif"><i><span style="font-style:normal"><i></i></span><i></i></i></font></div></div></div>
<font face="times new roman, serif"><br><br></font><div class="gmail_quote"><font face="times new roman, serif">On Mon, Mar 4, 2013 at 11:37 PM, Paul Eggert <span dir="ltr"><<a href="mailto:eggert@cs.ucla.edu" target="_blank">eggert@cs.ucla.edu</a>></span> wrote:<br>
</font><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><font face="times new roman, serif">That discussion seems to be predicated on the assumption that<br>
tz zone names can and do "disappear", but they don't. For example,<br>
we renamed Asia/Calcutta to Asia/Kolkata, but kept the old name<br>
as an alias for the new one.<br>
<br>
I'm not sure it's worth my time to join that discussion (I am<br>
already on too many mailing lists) but you might want to forward<br>
this information.<br>
</font></blockquote></div><br></div></div>