Re: If a class Child inherits from Parent, how to implement Child.some_method if Parent.some_method() returns Parent instance ?

[Rhodri James]

On Thu, 29 Oct 2009 22:45:45 -0000, metal <metal...@gmail.com> wrote:

Consider the following:

[fixed to actually inherit...]

########################################
class Parent:
        def some_method(self):
                return Parent(...)
class Child(Parent):
        pass
########################################

Child().some_method() returns a Parent instance.

We can rewrite Parent like this to avoid that

########################################
class Parent:
        def some_method(self):
                return self.__class__(...)
class Child(Parent):
        def some_method(self):
                return Parent.some_method(self)
########################################

But this style makes code full with ugly  self.__class__

Any standard/pythonic way out there?

That's a perfectly good way to do it.  If __class__ really
offends you that much, wrap it in another (probably static)
method:

class Parent(object):
  def some_method(self):
    return self.another_one(...)

  @staticmethod
  def another_one(...):
    return Parent(...)

class Child(Parent):
  def some_method(self):
    return Parent.some_method(self)

  @staticmethod
  def another_one(...):
    return Child(...)

--
Rhodri James *-* Wildebeest Herder to the Masses
--
http://mail.python.org/mailman/listinfo/python-list