[tz] [PATCH 3/3] * europe (Europe/Vaduz): Now a link to Europe/Zurich.

[Russ Allbery]

Here, incidentally, is exactly where it would be nice to be able to link
to another entry.  Assuming for the sake of argument that we want to
retain the current pre-standardized-time behavior for Europe/Vaduz, we
could change:

Zone    Europe/Vaduz    0:38:04 -       LMT     1894 Jun
                        1:00    -       CET     1981
                        1:00    EU      CE%sT

to:

Zone    Europe/Vaduz    0:38:04 -       LMT     1894 Jun
                        => Europe/Zurich

where the "=> Europe/Zurich" syntax (that I just made up, and which
doubtless could be made much better) says to apply the rules of that zone
for the time period of that rule.  If you apply a winnowing threshold
after June of 1894, the zone would then just become a link; if you don't,
it would be a separate zone but would just mirror Europe/Zurich.

You could even potentially allow such a line to have an end date, so that
you could directly represent "followed all the rules of another zone
during ths time range" without duplicating those rules.

Without that, applying the DST corrections from 1941 to 1942 to
Europe/Vaduz as well requires copying them from Europe/Zurich, which loses
the piece of information that they're not confirmed rules specific for
Liechtenstein but rather copied rules from Europe/Zurich under the
assumption that they were probably the same.  You can put that information
back in comments, of course, but it still would be nice to be able to
represent it in the data format.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>