On 2020-07-06, Frank Millman <frank at chagford.com> wrote:
> On 2020-07-06 2:06 PM, Jon Ribbens via Python-list wrote:
>> While I agree entirely with your point, there is however perhaps room
>> for a bit more helpfulness from the json module. There is no sensible
>> reason I can think of that it refuses to serialize sets, for example.
>> Going a bit further and, for example, automatically calling isoformat()
>> on date/time/datetime objects would perhaps be a bit more controversial,
>> but would frequently be useful, and there's no obvious downside that
>> occurs to me.
> I may be missing something, but that would cause a downside for me.
> I store Python lists and dicts in a database by calling dumps() when
> saving them to the database and loads() when retrieving them.
> If a date was 'dumped' using isoformat(), then on retrieval I would not
> know whether it was originally a string, which must remain as is, or was
> originally a date object, which must be converted back to a date object.
> There is no perfect answer, but my solution works fairly well. When
> dumping, I use 'default=repr'. This means that dates get dumped as
> 'datetime.date(2020, 7, 6)'. I look for that pattern on retrieval to
> detect that it is actually a date object.
There is no difference whatsoever between matching on the repr output
you show above and matching on ISO-8601 datetimes, except that at least
ISO-8601 is an actual standard. So no, you haven't found a downside.