[Python-Dev] Store timestamps as decimal.Decimal objects (original) (raw)

Victor Stinner victor.stinner at haypocalc.com
Tue Jan 31 13:08:21 CET 2012

Hi,

2012/1/31 Matt Joiner <anacrolix at gmail.com>:

Sounds good, but I also prefer Alexander's method. The type information is already encoded in the class object.

Ok, I posted a patch version 6 to use types instead of strings. I also prefer types because it solves the "hidden import" issue.

This way you don't need to maintain a mapping of strings to classes, and other functions/third party can join in the fun without needing access to the latest canonical mapping. Lastly there will be no confusion or contention for duplicate keys.

My patch checks isinstance(format, type), format.module and format.name to do the "mapping". It is not a direct mapping because I don't always call the same method, the implementation is completly differenet for each type.

I don't think that we need user defined timestamp formats. My last patch provides 5 formats:

(I removed the timespec format, I consider that we don't need it.)

Examples:

>>> time.time()
1328006975.681211
>>> time.time(format=int)
1328006979
>>> time.time(format=decimal.Decimal)
Decimal('1328006983.761119')
>>> time.time(format=datetime.datetime)
datetime.datetime(2012, 1, 31, 11, 49, 49, 409831)
>>> print(time.time(format=datetime.timedelta))
15370 days, 10:49:52.842116

If someone wants another format, he/she should pick up an existing format to build his/her own format.

datetime.datetime and datetime.timedelta can be used on any function, but datetime.datetime format gives surprising results on clocks using an arbitrary start like time.clock() or time.wallclock(). We may raise an error in these cases.

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