Can I use clean Python 3 super()
syntax in Python 2.5.6?
Maybe with some kind of __future__
import?
You cannot use a bare super()
call that contains no type/class. Nor can you implement a replacement for it that will work. Python 3.x contains special support to enable bare super()
calls (it places a __class__
cell variable in all functions defined within a class - see PEP 3135
Update
As of Python 2.6+, bare super()
calls can be used via the future
Python package. See posita's answer for an explanation.
I realize this question is old, and the selected answer may have been correct at the time, but it's no longer complete. You still can't use super()
in 2.5.6, but python-future
provides a back-ported implementation for 2.6+:
Install python-future
with:
% pip install future
The following shows the redefinition of super
under builtins
:
% python
...
>>> import sys
>>> sys.version_info[:3]
(2, 7, 9)
>>>
>>> super
<type 'super'>
>>>
>>> from builtins import *
>>> super
<function newsuper at 0x000000010b4832e0>
>>> super.__module__
'future.builtins.newsuper'
It can be used as follows:
from builtins import super
class Foo(object):
def f(self):
print('foo')
class Bar(Foo):
def f(self):
super().f() # <- whoomp, there it is
print('bar')
b = Bar()
b.f()
which outputs
foo
bar
If you use pylint
, you can disable legacy warnings with the comment:
# pylint: disable=missing-super-argument
No you cannot. But you can use Python 2's super()
in Python 3.
Note This is a terrible "solution", I post it only to make sure you don't do this at home!
I repeat: do not do this
One may think about using this mixin
class Super(object):
def super(self):
return super(self.__class__, self)
to obtain a self.super()
:
class A(object, Super):
def __init__(self):
print "A"
class B(A):
def __init__(self):
print "B"
self.super().__init__()
yielding:
>>> a = A()
A
>>> b = B()
B
A
But beware: This self.super()
is not equivalent to super(B, self)
- if A
also called self.super().__init__()
, the construction of a B
would cause the A
constructor to call itself indefinitely, since self.__class__
will remain B
. This is due to the lack of the __class__
mentioned in the accepted answer. You can possibly work around this issue with a hidden state machine or a sophisticated metaclass that e.g. checks the actual class's position in self.__class__.mro()
, but is it really worth it? Probably not...
来源:https://stackoverflow.com/questions/7718684/can-i-use-python-3-super-in-python-2-5-6