Re: The opener parameter of Python 3 open() built-in

From	Terry Reedy <tjreedy@udel.edu>
Subject	Re: The opener parameter of Python 3 open() built-in
Date	2012-09-04 19:16 -0400
References	(1 earlier) <mailman.139.1346678967.27098.python-list@python.org> <504555a5$0$29978$c3e8da3$5496439d@news.astraweb.com> <k24tt1$jv8$1@ger.gmane.org> <k25k2r$8tc$1@ger.gmane.org> <CAPTjJmosFG6Xjf-ruwchF8Jadnwv8+tnF8J5utGPH13v1FGoFw@mail.gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.199.1346800623.27098.python-list@python.org> (permalink)

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On 9/4/2012 6:18 PM, Chris Angelico wrote:
> On Wed, Sep 5, 2012 at 5:16 AM, Terry Reedy <tjreedy@udel.edu> wrote:
>> io.open depends on a function the returns an open file descriptor. opener
>> exposes that dependency so it can be replaced.
>
> I skimmed the bug report comments but didn't find an answer to this:
> Why not just monkey-patch?

As far as I know, one can only use normal Python code to monkey patch 
modules written in Python. Even then, one can only rebind names stored 
in writable dicts -- the module dict and class attribute dicts. The 
attributes of function code objects are readonly. Replacing a code 
object is not for the faint of heart.

io.py mostly loads _io compiled from C.

-- 
Terry Jan Reedy

Thread

The opener parameter of Python 3 open() built-in Marco <marco_u@nsgmail.com> - 2012-09-03 14:32 +0200
  Re: The opener parameter of Python 3 open() built-in Dave Angel <d@davea.name> - 2012-09-03 09:05 -0400
    Re: The opener parameter of Python 3 open() built-in Marco <marco_u@nsgmail.com> - 2012-09-03 15:33 +0200
    Re: The opener parameter of Python 3 open() built-in Marco <marco.buttu@gmail.com> - 2012-09-03 15:33 +0200
  Re: The opener parameter of Python 3 open() built-in Christian Heimes <lists@cheimes.de> - 2012-09-03 15:29 +0200
    Re: The opener parameter of Python 3 open() built-in Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-04 01:13 +0000
      Re: The opener parameter of Python 3 open() built-in Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-09-03 23:19 -0400
        Re: The opener parameter of Python 3 open() built-in Ben Finney <ben+python@benfinney.id.au> - 2012-09-04 15:12 +1000
          Re: The opener parameter of Python 3 open() built-in Ben Finney <ben+python@benfinney.id.au> - 2012-09-04 15:20 +1000
          Re: The opener parameter of Python 3 open() built-in Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-09-04 14:44 -0400
        Re: The opener parameter of Python 3 open() built-in Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-04 05:25 +0000
          Re: The opener parameter of Python 3 open() built-in Ben Finney <ben+python@benfinney.id.au> - 2012-09-04 15:45 +1000
      Re: The opener parameter of Python 3 open() built-in Serhiy Storchaka <storchaka@gmail.com> - 2012-09-04 15:58 +0300
      Re: The opener parameter of Python 3 open() built-in Terry Reedy <tjreedy@udel.edu> - 2012-09-04 15:16 -0400
      Re: The opener parameter of Python 3 open() built-in Chris Angelico <rosuav@gmail.com> - 2012-09-05 08:18 +1000
      Re: The opener parameter of Python 3 open() built-in Terry Reedy <tjreedy@udel.edu> - 2012-09-04 19:16 -0400
      Re: The opener parameter of Python 3 open() built-in Antoine Pitrou <solipsis@pitrou.net> - 2012-09-06 00:34 +0000
        Re: The opener parameter of Python 3 open() built-in Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-06 06:34 +0000
  Re: The opener parameter of Python 3 open() built-in Serhiy Storchaka <storchaka@gmail.com> - 2012-09-03 19:06 +0300
  Re: The opener parameter of Python 3 open() built-in Serhiy Storchaka <storchaka@gmail.com> - 2012-09-04 16:01 +0300

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