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Date: Thu, 09 Jan 2014 07:56:20 -0800
From: Ethan Furman <ethan@stoneleaf.us>
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To: python-list@python.org
Subject: Re: the Gravity of Python 2
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On 01/09/2014 06:57 AM, Chris Angelico wrote:
> On Fri, Jan 10, 2014 at 1:14 AM, Roy Smith <roy@panix.com> wrote:
>>
>
> Thanks for this collection! Now we can discuss.

[snip]

>> Datetimes are self-describing.  If I have a datetime or a timedelta, I
>> know what I've got.  I've written more than one bug where I assumed a
>> number somebody handed me was in seconds but it turned out to be in ms.
>> That can never happen with a timedelta.  We do a lot of stuff in
>> javascript, where times are ms, so this is a common problem for us.
>
> Sure. Though that's no different from other cases where you need
> out-of-band information to understand something, as we've just been
> discussing in the threads about text handling - if you have a puddle
> of bytes, you can't decode them to text without knowing what the
> encoding is. [1] If your data's coming from JS, it won't be a
> timedelta, it'll be a number; at some point you have to turn that into
> a timedelta object, so you still have the same problem.

Yup, and you do at the boundary instead of having a float wandering through your code with an easily forgotten meta-data 
type.


> So what I'm seeing here is that the direct use of a time_t will cover
> everything in an ugly way, but that a class wrapping it up could fix
> that. And fundamentally, the only problem with datetime (which, for
> the most part, is exactly that wrapper) is that it's unobvious how to
> get a simple UTC timestamp.

It has at least one other problem:  bool(midnight) == False.

--
~Ethan~


> [1] Yes, I said "puddle of bytes". What would you call it? Am
> interested to hear!

I think that's a perfect name!  :)