[Datetime-SIG] Computing .dst() as a timedelta

Chris Angelico rosuav at gmail.com
Wed Sep 23 01:05:07 CEST 2015

On Wed, Sep 23, 2015 at 4:02 AM, Alexander Belopolsky
<alexander.belopolsky at gmail.com> wrote:
> On Tue, Sep 22, 2015 at 1:40 PM, Chris Angelico <rosuav at gmail.com> wrote:
>> That's why it's safest to be clear about UTC
>> usage, and honestly, this has nothing to do with what a computer can
>> and can't be taught to do - it's all about what humans can get their
>> heads around.
> UTC is no better than DMT (Dragonlance Mean Time).  In fact, I think I will
> have easier time explaining DMT to a ten year old than explaining UTC.   If
> your team can agree on a natural language, they can agree on a timescale.
> It does not matter what it is.  If uniformity was a universal virtue, we
> would all be speaking Esperanto by now.

If I were creating my own standard out of thin air, then yes, it
wouldn't make a lot of difference, and I could pick anywhere. (There
are a few invariants that I'd maintain, such as that it should "tick"
the same way our civil clocks do - one second equals one civil second,
and they're packaged up into hours and days the same way - but it
doesn't matter what the exact offset is.) But UTC already exists, and
that gives it an inherent advantage. I've never tried to explain DMT
to anyone, but explaining a simplified form of GMT/UTC (ignore leap
seconds, ignore relativity, ignore UT0/UT1 etc) is pretty easy - it's
just a well-known time zone that has no DST.


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