Rules that Don't Exist

Bill Seymour bill-at-the-office at
Sat Nov 24 13:12:55 UTC 2007

On 11/23/07, Ken Pizzini <tz_ at> wrote:
> The important thing to remember is that the rules specify *transitions*.

That's what I thought, too, until I realized that the SAVE and LETTER/S
columns specify states, not transitions.  Consider for example:

 Rule  US  1942 only  -  Feb   9  2:00     1:00  W # War
 Rule  US  1945 only  -  Aug 14  23:00u 1:00   P # Peace

The second of those is /not/ an instruction to set my clock ahead an hour.

But my real question was about the replacement text for "%s" in the Zone's
FORMAT when there has been no "transition" to set the LETTER/S initially.
Assuming an empty string is reasonable and works for the Europe/Zurich
example in zic.8.txt; but it gives me "CT" for a similar case in

I'm guessing that it really should be "CST".  If that's right, we need
some algorithm for getting the "S" from the existing data.  Maybe
something like:

    When changing to a named Rule before the first one exists, move
    forward in time to the first with a SAVE of 0 and use the LETTER/S
    from that.

But my guess might be wrong...I don't know, which is why I'm asking.


--Bill Seymour

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