[Pythonmac-SIG] Extending datetime

[Joel Bender]

I'm having trouble extending the datetime class.  My suspicion is 
that datetime is not a real class, but something else.  And this 
probably isn't a Mac specific thing.

     Python 2.3 (#2, Jul 30 2003, 11:45:28)
     [GCC 3.1 20020420 (prerelease)] on darwin
     Type "help", "copyright", "credits" or "license" for more information.
     >>> from datetime import datetime
     >>> datetime(1,2,3)
     datetime.datetime(1, 2, 3, 0, 0)

So far, so good.  The class constructor needs at least three parameters.

     >>> class X(datetime):
     ...     def __init__(self):
     ...         datetime.__init__(self,1,2,3)
     ...

My class X extends datetime and provides them.

     >>> X()
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     TypeError: function takes at least 3 arguments (0 given)

Huh?

     >>> X(4,5,6)
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     TypeError: __init__() takes exactly 1 argument (4 given)

This error I expect, X.__init__ should have only one argument. Now I 
try something else:

     >>> class Y(datetime):
     ...     def __init__(self,*args):
     ...             print "!", args
     ...             datetime.__init__(self,1,2,3)
     ...

My intent is to parse the args at some point and initialize the base 
class in a variety of different ways.

     >>> Y()
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     TypeError: function takes at least 3 arguments (0 given)

I still don't understand, but at least it's consistent :).

     >>> Y(4,5,6)
     ! (4, 5, 6)
     Y(4, 5, 6, 0, 0)

Looks good so far.

     >>> y = Y(4,5,6)
     ! (4, 5, 6)
     >>> str(y)
     '0004-05-06 00:00:00'

Huh?  Isn't the year supposed to be 1?



Joel