[Python-Dev] PEP 495 Was: PEP 498: Literal String Interpolation is ready for pronouncement

[Alexander Belopolsky]

On Tue, Sep 8, 2015 at 8:27 PM, Guido van Rossum <guido at python.org> wrote:

> Now if only PEP 495 could be as easy... :-)
>

I think we nailed the hard issues there.   The next update will have a
restored hash invariant and == that satisfies all three axioms of
equivalency.  I am not making a better progress because I am debating with
myself about the fate of < and > comparisons.  Cross-zone comparisons
strike in full force there as well because two times ordered in UTC may
appear in the opposite order in the local timezone where the clock is moved
back.  Note that I saved the hash invariant and the transitivity of == at
the expense of the loss of trichotomy in comparisons (we will have pairs of
aware datetimes that are neither equal nor < nor >).  I don't think we need
to change anything with < and > comparisons, but I am trying to come up
with the arguments that will at least be convincing to myself.  (I suspect
that if I am not the only one who worries about this, the other such people
can be counted by the values of the fold flag. :-)
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