[Dev] Date / Time types

[Jeffrey Harris]

Hi Ted,

I've forgotten now why exactly we're using mxDateTime instead of the 
standard Python 2.3 datetime library.  Can someone remind me?  If I 
didn't know better, I'd say datetime seems adequate as an internal 
representation for solitary dates.

We'll need to do localization of dates, it's not clear to me why we'd 
want to store something like ICU datatypes internally instead of 
datetime.  Would it be terribly expensive to store standard datetimes 
internally and use a more complicated package to display?

We'll need to use something like pytz so we can associate concrete 
timezone information with our times in a cross platform way.

The main area of question around dates and times I have is recurrence. 
Lisa and I were chatting recently about date/times in the context of 
import/export to iCalendar.  If we'd like time sensitive data to export 
smoothly to iCalendar, it would be nice (though certainly not essential) 
for recurrence to be represented internally in a way that maps easily 
onto rfc2445's concepts of recurrence rules.  We can always pick a large 
but finite subset of an infinite recurrence rule and import/export them 
that way, but that seems inelegant if we can avoid it.

For vobject, I'm using dateutil (https://moin.conectiva.com.br/DateUtil) 
for representing iCalendar recurrence rules.

Sincerely,
Jeffrey