[Python-Dev] Sub-claasing pathlib.Path seems impossible

[Guido van Rossum]

It does sound like subclassing Path should be made easier.

On Sat, May 2, 2015 at 1:30 PM, Ryan Gonzalez <rymg19 at gmail.com> wrote:

> http://stackoverflow.com/a/29880095/2097780
>
> My favorite thing about Python is that it's so easy to be evil. ;)
>
>
> On Fri, May 1, 2015 at 2:30 PM, Christophe Bal <projetmbc at gmail.com>
> wrote:
>
>> Hello.
>>
>> In this post
>> <http://stackoverflow.com/questions/29850801/simple-subclassing-pathlib-path-does-not-work/29854141#29854141>,
>> I have noticed a problem with the following code.
>>
>> from pathlib import Path
>>> class PPath(Path):
>>>     def __init__(self, *args, **kwargs):
>>>         super().__init__(*args, **kwargs)
>>>
>>> test = PPath("dir", "test.txt")
>>>
>>>
>> This gives the following error message.
>>
>>
>>
>>> Traceback (most recent call last):
>>>   File "/Users/projetmbc/test.py", line 14, in <module>
>>>     test = PPath("dir", "test.txt")
>>>   File "/anaconda/lib/python3.4/pathlib.py", line 907, in __new__
>>>     self = cls._from_parts(args, init=False)
>>>   File "/anaconda/lib/python3.4/pathlib.py", line 589, in _from_parts
>>>     drv, root, parts = self._parse_args(args)
>>>   File "/anaconda/lib/python3.4/pathlib.py", line 582, in _parse_args
>>>     return cls._flavour.parse_parts(parts)AttributeError: type object 'PPath' has no attribute '_flavour'
>>>
>>>
>> This breaks the sub-classing from Python point of view. In the post
>> <http://stackoverflow.com/questions/29850801/simple-subclassing-pathlib-path-does-not-work/29854141#29854141>,
>> I give a hack to sub-class Path but it's a bit Unpythonic.
>>
>> *Christophe BAL*
>> *Enseignant de mathématiques en Lycée **et développeur Python amateur*
>> *---*
>> *French math teacher in a "Lycée" **and **Python **amateur developer*
>>
>> _______________________________________________
>> Python-Dev mailing list
>> Python-Dev at python.org
>> https://mail.python.org/mailman/listinfo/python-dev
>> Unsubscribe:
>> https://mail.python.org/mailman/options/python-dev/rymg19%40gmail.com
>>
>>
>
>
> --
> Ryan
> [ERROR]: Your autotools build scripts are 200 lines longer than your
> program. Something’s wrong.
> http://kirbyfan64.github.io/
>
>
> _______________________________________________
> Python-Dev mailing list
> Python-Dev at python.org
> https://mail.python.org/mailman/listinfo/python-dev
> Unsubscribe:
> https://mail.python.org/mailman/options/python-dev/guido%40python.org
>
>


-- 
--Guido van Rossum (python.org/~guido)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-dev/attachments/20150503/94b3c35f/attachment-0001.html>