[issue5094] datetime lacks concrete tzinfo impl. for UTC

[Alexander Belopolsky]

Alexander Belopolsky <belopolsky at users.sourceforge.net> added the comment:

On Sun, Jun 13, 2010 at 10:09 AM, Mark Dickinson <report at bugs.python.org> wrote:
..
> - Should the PyDateTime_TimeZone struct definition go into
> datetime.h, so that it's avaiable if you want to export any C-API
> functions later on?
>
The original patch had this in the header file, but I moved it down to .c during dst debate. (See msg107186, point 3.)  In the future we may add accessor functions to datetime.h, but this can be done without exposing the C struct.
 
> - If you're not allowing subclassing, then presumably you don't need
>  the new_timezone / new_timezone_ex dance?
>
I agree, but if you don't mind, I will not change it at this point.  There is a small chance that there will be an outcry for supporting subclassing and we will put that back in. Also, issue #2267 debate may result in removing the dance from other factory functions. (If the camp saying that the base class has no idea how to construct subclass instances wins.) Not a big deal either way, though.

> - For clarity, please consider adding parentheses in:
>
>    self = (PyDateTime_TimeZone *)type->tp_alloc(type, 0);
>

will do.  PEP 7 does not mention that, but probably should. 

> - Whitespace issues: there are a couple of tabs in the source (at
> around lines 810, 3388, 3390), and an overly long line (>79
> characters) at around line 3365.
>

Thanks.  I thought I checked those.  Maybe I should take over issue8912 as a community service. :-) 

> - Please add a brief comment before the added C functions (like
> new_timezone_ex) explaining their purpose.
>

Will do.

> - I wonder whether __ne__ should return the correct result (rather
> than returning NotImplemented) for timezone instances. 

Will do.

>  OTOH, I agree with the decision not to allow timezone order
> comparisons (though I bet they get requested at some point).

I will support such request.  It is very easy to implement (just remove the check that disallows it) and makes perfect sense.  I left them out only because it is easier to add features than to remove in the future and I don't want to debate this now.


>
> - There doesn't seem to be any mention of timezone.min or timezone.max
> in the docs.  Is this deliberate?
>
Yes.  Without ordering, having min and max is rather strange.  I wanted to expose these for testing and will definitely document them when (and if) order comparisons are implemented.  For now, let's keep them as easter eggs.

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<http://bugs.python.org/issue5094>
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