[Python-Dev] Status on PEP-431 Timezones

Terry Reedy tjreedy at udel.edu
Mon Jul 27 21:42:31 CEST 2015

On 7/27/2015 3:14 PM, Tim Peters wrote:

> [Terry Reedy]
>> I think using the word 'naive' is both inaccurate and a mistake.  The issue
>> is civil or legal time versus STEM time, where the latter includes
>> applications like baking cakes.
> Sorry, never heard of "STEM time" before - & a quick Google search didn't help.

Searching for 'STEM' to discover the meaning of the acronym displays, 
for me, after the second
"STEM is an acronym referring to the academic disciplines of science, 
technology, engineering and mathematics." STEM time is the time used in 
science, technology, engineering and mathematics, with the added note 
indicating that I mean for technology and engineering to be taken 
broadly, to include all uses of actual (natural) elapsed time, as 
opposed to occasionally artificial government time.

>> The idea that an hour can be sliced out of a somewhat random March day and
>> inserting it into a somewhat random October day is rather sophisticated.  It
>> came from the minds of government bureaucrats.  It might be smart, dumb, or
>> just a cunning way for civil authorities to show who is in charge by making
>> us all jump.  But not 'naive'.
> I agree.  Python's "naive time" single-timezone arithmetic
> intentionally ignores all that:  it ignores leap seconds, it ignores
> DST transition points, it ignores governments deciding to change the
> base UTC offset within a pre-existing time zone, ...  It's time soooo
> naive that it thinks 24 hours is the same thing as a day ;-)

To me, having 1 day be 23 or 25 hours of elapsed time on the DST 
transition days, as in Paul's alarm example, hardly ignores the 
transition point.

Terry Jan Reedy

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