On Wed, 28 Jan 2015 11:46:38 +1100 Steven D'Aprano email@example.com wrote:
The obvious question is "What does Postgresql do?"
Same for use-cases, which Antoine asked for. The primary use-case is to improve compatibility with Postgresql while still treating the full range of dates up to and including date.max as regular dates.
I'm not convinced that numpy is the right library to follow here. Unless there are cases where you would perform calculations with Not-A-Time, an exception would probably be better suited.
I should add that I mentioned Numpy as a datapoint, but knowledgeable people I talked to generally agreed that Numpy's datetime64/timedelta64 design isn't very good (actually, it has an even wonkier feature that's only exposed internally AFAIK). So "Not-A-Time" need not necessarily be implemented in the stdlib ;)