[tz] A New Rule? (was McMurdo/South Pole)

[Alan Barrett]

On Sun, 22 Sep 2013, Bill Seymour wrote:
>A partly-baked idea to solve the more general problem
>of when zones appear and disappear:  would it make
>sense to have another kind of entry in the zone RULES
>column to indicate that we should now follow another
>zone's practice?  How about the keyword, Zone, a
>space, and the name of the other zone, with the next
>column following whitespace, if present, being the
>[UNTIL] column?

I liked the syntax proposed by Andy Lipscomb on 5 Sep 
2013, with "=" as a magic character in the GMTOFF, 
RULES, and FORMAT fields of a Zone record.  See 
<http://mm.icann.org/pipermail/tz/2013-September/019952.html>.  
He gave this example:

Zone America/North_Dakota/New_Salem -6:45:39 - LMT 1883 Nov 18 12:14:21
     =America/Denver        =    =    2003 Oct 26 02:00
     =America/Chicago       =    =

which would mean: America/North/Dakota/New_Salem used LMT until 
a specified date, then followed the same rules as America/Denver 
until a specified date, and now follows the same rules as 
America/Chicago into the future.

--apb (Alan Barrett)