Extra base class in hierarchy

[Ian Kelly]

On Nov 19, 2016 11:22 AM, "Victor Porton" <porton at narod.ru> wrote:

Consider

class FinalTreeNode(object):
    def childs(self):
        return []

class UsualTreeNode(FinalTreeNode)
    def childs(self):
        return ...

In this structure UsualTreeNode derives from FinalTreeNode.


This looks odd because "final" in OOP usually denotes something that will
not be further inherited.

Is it better to introduce an extra base class?


Without knowing what UsualTreeNode and FinalTreeNode are it's hard to say.


class BaseTreeNode(object):
    def childs(self):
        return []

# The same functionality as BaseTreeNode, but logically distinct
class FinalTreeNode(BaseTreeNode):
    pass


That's a bit of a code smell. Why do you need a subclass if the
implementation is the same? Probably you should implement the common parts
in the base class and differentiate both of the subclasses.

Also a pet peeve of mine is the word "base" in class names. Just call it
TreeNode.