[Python-Dev] Interop between datetime and mxDateTime (original) (raw)

Tim Peters tim.one@comcast.net
Mon, 13 Jan 2003 20:21:05 -0500

[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?