[Datetime-SIG] Local time disambiguation proposal

[Alexander Belopolsky]

On Thu, Jul 30, 2015 at 2:15 PM, Alexander Walters
<tritium-list at sdamon.com> wrote:
> We are not talking about implementing the POSiX argument to mktime, and I
> dont think anyone on the list ever was.  .is_dst is a bool flag for 'if set,
> the time represented is in the DST time, if not set, it is in the non-DST
> time'.
>
> '.first' doesnt even imply a bool.  "First what?" someone might ask.

I have no emotional attachment to any particular name.  If you like
"is_first" better than "first" on the grammatical grounds - I have no
problem changing the spelling.

I do have two problems with calling it isdst:

1. Whether we want to implement the POSIX standard or not, but
tm_isdst member is the POSIX solution to the problem at hand and if we
give datetime objects a member variable called isdst, but change the
semantics, we will see no end of bug reports.  (And since no one
understands POSIX semantics, we have no choice but to change them. :-)

2. It will be very confusing to have t.is_dst ≠ t.dst()  which will
happen whenever you have an ambiguity due to a change in the standard
time.