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Re: Returning a custom file object (Python 3)

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On Thu, May 28, 2015 at 5:04 PM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
>> This does appear to work. Whether or not it's a good idea is a
>> separate question.
>
>
> And this is EXACTLY the sort of use-case that having __class__ be writable
> is intended to solve. So this is exactly the solution I was after, thank
> you. Er... except for one little problem... in Python 3.3:
>
> py> f = open("/tmp/a", "r")
> py> f.__class__ = MyFile
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> TypeError: __class__ assignment: only for heap types
>
>
> So it doesn't work for me. What version of Python are you using?

Huh, didn't even think to check other versions.

$ python3
Python 3.5.0b1+ (default:7255af1a1c50+, May 26 2015, 00:39:06)
[GCC 4.9.2] on linux

It's a build fresh from source control around about this weekend (some
time after feature freeze, obviously, but beyond that all I know is
what you see there). I guess this is pretty new; trying the same thing
on 3.4.2 doesn't work. But hey! 3.5 will be out soon...

ChrisA

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Thread

Returning a custom file object (Python 3) Steven D'Aprano <steve@pearwood.info> - 2015-05-28 12:16 +1000
  Re: Returning a custom file object (Python 3) Ben Finney <ben+python@benfinney.id.au> - 2015-05-28 12:40 +1000
    Re: Returning a custom file object (Python 3) Marko Rauhamaa <marko@pacujo.net> - 2015-05-28 08:29 +0300
      Re: Returning a custom file object (Python 3) Chris Angelico <rosuav@gmail.com> - 2015-05-28 15:49 +1000
        Re: Returning a custom file object (Python 3) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-28 17:04 +1000
          Re: Returning a custom file object (Python 3) Chris Angelico <rosuav@gmail.com> - 2015-05-28 19:06 +1000
      Re: Returning a custom file object (Python 3) Gary Herron <gherron@digipen.edu> - 2015-05-27 22:56 -0700
        Re: Returning a custom file object (Python 3) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-28 16:52 +1000
  Re: Returning a custom file object (Python 3) Ben Finney <ben+python@benfinney.id.au> - 2015-05-28 12:34 +1000
  Re: Returning a custom file object (Python 3) Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2015-05-28 10:29 +0100

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