[Python-ideas] Please reconsider the Boolean evaluation of midnight

[Chris Angelico]

On Thu, Mar 6, 2014 at 8:36 AM, Alexander Belopolsky
<alexander.belopolsky at gmail.com> wrote:
> On Wed, Mar 5, 2014 at 4:10 PM, Alex Gaynor <alex.gaynor at gmail.com> wrote:
>>
>> I strongly support fixing this issue. This behavior is so fundamentally
>> nonsensical that resolving it is worth the potential compatibility issues.
>
>
> Does anyone know a language that (a) has a time-of-day class in stdlib; (b)
> allows
> instances of that class to be used in boolean context, and (c) has a
> midnight
> represented by an instance that is truthy?

Pike fits all three of those, but (c) is trivially true: any object in
Pike is truthy. Of course, you can choose to represent time-of-day
with an integer, in which case an integer of 0 will be false; but if
you use floating-point (for sub-second accuracy), then it's still
safe, because any float is truthy (even 0.0 - and if you think that's
illogical, consider that expecting 0.0 to be false is effectively
making an implicit equality comparison, with all the issues of
equality comparisons on floats _plus_ the issues of doing that
implicitly). If Python didn't have to worry about backward
compatibility (that is, if this were being implemented new now), then
I'd say a null time range should be false, but any date, datetime, or
time, regardless of what it represents, is true. Maybe there could be
a "null date" value that isn't a date, but None should be able to do
that.

ChrisA