[Python-Dev] Interop between datetime and mxDateTime

[Tim Peters]

[Guido]
> The proposal also recomments an abstract base type, "basetime", for
> all time types.  Without this, cmp() is hard to do (see Tim's post for
> explanation; we don't want datetime objects to be comparable to
> objects with arbitrary other types, because the default comparison iss
> meaningless).
>
> This could be a pure "marker" type, like "basestring".  Marc-Andre,
> if we export basetime from the core, can mxDateTime subclass from
> that?

Let me ask a question:  when I tried to make datatime.tzinfo a pure "marker"
type, I eventually had to give up, because I absolutely could not make it
work with pickling (and recalling that pickles produced by datetime.py had
to be readable by datetimemodule.c, and vice versa).  Instead I had to make
it instantiable (give it an init method that didn't complain), and require
that tzinfo subclasses also have an __init__method callable with no
arguments.  Are we able to get away with basestring because pickle already
has deep knowledge about Python's string types?

[Mark Hammond]
> I have the exact same issue for my COM time objects, and like MAL, just
> recently started thinking about it.
>
> Certainly, such a subclass would help me enormously, and would
> probably make it quite simple for this to allow *any* datetime
> object to be passed to COM/Windows functions.

Well, I don't see that a basetime marker class alone would allow for that.
What else are you assuming?