Australia/Darwin 1945..2007

[Ken Pizzini]

On Tue, Jan 23, 2007 at 12:01:19PM +1100, Sean B. Durkin wrote:
> The data source file 'australasia' specifies that the Australia/Darwin
> zone uses the rule Aus from 1-May-1899 onwards. But the Aus rule is
> undefined for from 1945 onwards! I have copied the salient fragment of
> the australasia file to the bottom of this message.
> 
> Am I missing something here? or is the data inconsistent?

The data specifies when transitions between different UTC offsets
occur.  Since the Aus rule specifies no transitions after 1943-10-03,
and the Austrailia/Darwin zone specifies no other rulset to use
after that time, the interpretation is that the UTC offset for
the Darwin zone has remained unchanged since 1943-10-03.

> Moreover, as a general rule, how should one interpret the application
> of a tz "rule" for periods when the rule is not explicitly defined?

For times after the last defined rule: that there are no transitions to
apply, so the offset from UTC continues on unchanged from what it became
on the last specified transition.

For times before the first defined rule: that the earliest "standard time"
("SAVE == 0") rule applies.

		--Ken Pizzini