Arup Rakshit <a...@zeit.io> writes: > I basically had defined 4 classes. SimpleList be the base class for all the > other 3 classes. SortedList and IntList both being the child of the base > class SimpleList. They have a single inheritance relationship. Now I have the > last class called SortedIntList which has multiple inheritance relationship > with IntList and SortedList. The classes looks like: > > class SimpleList: > ... > def add(self, item): > self._items.append(item) > ... > > class SortedList(SimpleList): > ... > def add(self, item): > super().add(item) > self.sort() > ... > > class IntList(SimpleList): > ... > def add(self, item): > self._validate(item) > super().add(item) > ... > > class SortedIntList(IntList, SortedList): > ... > > > Now when I call the add method on the SortedIntList class’s instance, I was > expecting super.add() call inside the IntList class add method will dispatch > it to the base class SimpleList.
"super" is mainly for the use case of "mixin classes". By design, a "mixin class" must cope with an unknown inheritance structure and it must be able to cooperate with all classes in this structure. Especially, there must be a way to give all classes in the structure the chance to apply a method. This way is "super". As an example, think of "__init__". Each class in the class structure might need to perform its own initialization. To archieve this, "__init__" likely has the signature "__init__(self, **kw)" and each class pickes its initialization arguments from "kw" and then delegates to the next (in MRO) class with "super().__init__(kw)". This class may not be a base class of the current class. Thus, you use "super" when you want to delegate to an unknown class in the inheritance structure; if you want to delegate to a specific base class, then you do not use "super" but delegate explicitly to this class. -- https://mail.python.org/mailman/listinfo/python-list
