[Python-Dev] PEP 495 accepted (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Tue Sep 22 05:33:37 CEST 2015

On 22 September 2015 at 08:03, Guido van Rossum <guido at python.org> wrote:

Just so people know, over at the datetime-sig I've accepted PEP 495, which adds a fold flag to datetime objects to distinguish ambiguous times. This enables roundripping of conversions for those times where the local clock is moved backward (creating ambiguous times that could not be distinguished before).

Hurrah, and congratulations in particular on finding a name for the flag which is memorable, meaningful and succinct.

I would like to thank Alexander and Tim for their unrelenting work on this. The idea seems simple, but the details were excruciatingly hard to get right, given the strict backwards compatibility requirements.

I don't think I've seen a collision between mathematical and language level invariants that complex since the first time I had to figure out the conflict between container membership invariants and floating point NaN values (and this one is even more subtle).

I'm reading through the full PEP now, and really appreciating the thorough write up. Thanks to Alexander and Tim, and to all the folks involved in the extensive discussions!

Regards, Nick.

-- Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia

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