[newbie] super() and multiple inheritance

[Steven Bethard]

hermy wrote:
> As I understand it, using super() is the preferred way to call
> the next method in method-resolution-order. When I have parameterless
> __init__ methods, this works as expected.
> However, how do you solve the following simple multiple inheritance
> situation in python ?
> 
> class A(object):
>     def __init__(self,x):
>         super(A,self).__init__(x)
>         print "A init (x=%s)" % x
> 
> class B(object):
>     def __init__(self,y):
>         super(B,self).__init__(y)
>         print "B init (y=%s)" % y
> 
> class C(A,B):
>     def __init__(self,x,y):
>         super(C,self).__init__(x,y)  <-------- how to do this ???
>         print "C init (x=%s,y=%s)" % (x,y)

Unfortunately, super() doesn't mix too well with hierarchies that change 
the number of arguments to a method.  One possibility:

     class A(object):
         def __init__(self, x, **kwargs):
             super(A, self).__init__(x=x, **kwargs)
             print "A init (x=%s)" % x

     class B(object):
         def __init__(self, y, **kwargs):
             super(B, self).__init__(y=y, **kwargs)
             print "B init (y=%s)" % y

     class C(A,B):
         def __init__(self, x, y):
             super(C, self).__init__(x=x,y=y)
             print "C init (x=%s,y=%s)" % (x,y)

Then you can get::

     py> C(1, 2)
     B init (y=2)
     A init (x=1)
     C init (x=1,y=2)
     <__main__.C object at 0x00B9FA70>

But you have to make sure to always pass the **kwargs around.

STeVe