Why does super take a class name as the argument?

Glenn Andreas gandreas at no.reply
Sat Oct 16 04:49:23 CEST 2004


In article <mailman.5030.1097890551.5135.python-list at python.org>,
 Ed Leafe <ed at leafe.com> wrote:

> On Oct 15, 2004, at 7:36 PM, dataangel wrote:
> 
> > What's the going argument against it? Makes sense to me.
> 
> 	There are constructions in other languages whereby an call to the 
> superclass method does not require an explicit name of the current 
> class. When an inherited method is augmented in a subclass, the call to 
> the superclass version of the method doesn't require any class 
> specification; each class knows its own hierarchy.
> 

Except that in python a method can be changed to a different class, or 
even multiple classes, not to mention the fact that class parents can be 
dynamically reassigned.

In lanagues like Self, which is similar in its flexibility (but can 
actually handle this sort of thing), the method itself inherits from the 
object (it's kind of confusing to wrap your head around) so it can 
figure out things like this, but Python doesn't work that way.


> 	Think of it another way: since B can figure out how to execute a call 
> to a method that doesn't exist in B itself by looking into its class 
> hierarchy, why can't a call like self.super() execute the code that 
> would have been executed had the subclass not overridden the method in 
> the first place?
> 

When an instance "b" (or say "c" which is an instance of class "C" which 
is a subclass of "B") executes something like "self.foo", it starts 
looking at the class of self.  "super" actually starts further up the 
chain - if self is "c", you want "A.foo" and not "B.foo" (which is what 
you'd get if it tried to derive who "super" is based on "self").



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