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Re: Why no warnings when re-assigning builtin names?

Subject Re: Why no warnings when re-assigning builtin names?
From Philip Semanchuk <philip@semanchuk.com>
Date 2011-08-16 20:18 -0400
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On Aug 16, 2011, at 7:29 PM, Terry Reedy wrote:

> On 8/16/2011 1:15 PM, Gerrat Rickert wrote:
> 
>> I think that best practices would suggest that one shouldn't use
>> variable
>> names that shadow builtins (except in specific, special circumstances),
>> so I don't really think this would be an annoyance at all.  The number
>> of
>> *unwanted* warnings they'd get would be pretty close to zero.  OTOH, in
>> response to a question I asked on StackOverflow, someone posted a large
>> list of times where this isn't followed in the std lib, so there seems
>> to be a precedent for just using the builtin names for anything
>> one feels like at the time.
> 
> If you run across that again and email me the link, I will take a look and see if I think the issue should be raised on pydev. Of course, some modules *intentionally* define an open function, intended to be accessed as 'mod.open' and not as 'from mod import *; open'. Also, class/instance attributes can also reuse builtin names. But 'open = <True/False>' would be bad.


Hi Terry,
To generalize from your example, are you saying that there's a mild admonition against shadowing builtins with unrelated variable names in standard lib code?

Here's an example from Python 3.2.1's argparse.py, lines 466-473. "open" is shadowed on the second line.

        # clean up separators for mutually exclusive groups
        open = r'[\[(]'
        close = r'[\])]'
        text = _re.sub(r'(%s) ' % open, r'\1', text)
        text = _re.sub(r' (%s)' % close, r'\1', text)
        text = _re.sub(r'%s *%s' % (open, close), r'', text)
        text = _re.sub(r'\(([^|]*)\)', r'\1', text)
        text = text.strip()


Thanks
Philip

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Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-15 23:15 +0100
  Re: Why no warnings when re-assigning builtin names? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-08-16 11:32 +1000
    Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-15 23:23 -0400
      Re: Why no warnings when re-assigning builtin names? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-08-16 15:15 +1000
        Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-16 10:13 -0400
          Re: Why no warnings when re-assigning builtin names? rantingrick <rantingrick@gmail.com> - 2011-08-16 08:44 -0700
            Re: Why no warnings when re-assigning builtin names? Andrew Berg <bahamutzero8825@gmail.com> - 2011-08-16 12:23 -0500
        Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-16 16:12 +0100
        Re: Why no warnings when re-assigning builtin names? Ethan Furman <ethan@stoneleaf.us> - 2011-08-16 08:41 -0700
          Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-16 17:11 +0000
            Re: Why no warnings when re-assigning builtin names? Ethan Furman <ethan@stoneleaf.us> - 2011-08-16 10:48 -0700
            Re: Why no warnings when re-assigning builtin names? Tim Chase <python.list@tim.thechases.com> - 2011-08-16 13:34 -0500
        Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-16 11:31 -0400
        Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-16 11:38 -0400
        Re: Why no warnings when re-assigning builtin names? Ethan Furman <ethan@stoneleaf.us> - 2011-08-16 09:19 -0700
          Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-16 17:11 +0000
            Re: Why no warnings when re-assigning builtin names? Ethan Furman <ethan@stoneleaf.us> - 2011-08-16 10:43 -0700
              Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-16 18:56 +0000
                Re: Why no warnings when re-assigning builtin names? Terry Reedy <tjreedy@udel.edu> - 2011-08-16 19:32 -0400
                Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-16 23:49 +0000
                Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-17 01:02 +0100
                Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-17 01:35 +0000
                Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-17 08:27 +0100
                Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-17 16:33 +0000
                Re: Why no warnings when re-assigning builtin names? Terry Reedy <tjreedy@udel.edu> - 2011-08-16 22:10 -0400
            Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-16 19:23 +0100
        Re: Why no warnings when re-assigning builtin names? Tim Chase <python.list@tim.thechases.com> - 2011-08-16 11:10 -0500
        Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-16 12:32 -0400
          Re: Why no warnings when re-assigning builtin names? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-08-17 11:29 +1000
            Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-16 22:16 -0400
        Re: Why no warnings when re-assigning builtin names? Ethan Furman <ethan@stoneleaf.us> - 2011-08-16 10:07 -0700
        Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-16 17:11 +0000
          Re: Why no warnings when re-assigning builtin names? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-08-17 10:58 +1000
            Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-17 03:17 +0000
              Re: Why no warnings when re-assigning builtin names? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-08-17 18:15 +1000
                Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-17 16:33 +0000
                Re: Why no warnings when re-assigning builtin names? Ethan Furman <ethan@stoneleaf.us> - 2011-08-17 10:36 -0700
                Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-17 17:36 +0000
                Re: Why no warnings when re-assigning builtin names? Ethan Furman <ethan@stoneleaf.us> - 2011-08-17 11:13 -0700
                Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-17 18:09 +0000
                Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-17 18:42 +0100
                Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-17 17:38 +0000
                Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-17 19:02 +0100
                Re: Why no warnings when re-assigning builtin names? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-08-18 10:36 +1000
            Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-17 08:34 +0100
        RE: Why no warnings when re-assigning builtin names? "Gerrat Rickert" <grickert@coldstorage.com> - 2011-08-16 13:15 -0400
        Re: Why no warnings when re-assigning builtin names? Terry Reedy <tjreedy@udel.edu> - 2011-08-16 19:29 -0400
        Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-16 20:18 -0400
        Re: Why no warnings when re-assigning builtin names? Terry Reedy <tjreedy@udel.edu> - 2011-08-16 22:15 -0400
        Re: Why no warnings when re-assigning builtin names? Philip Semanchuk <philip@semanchuk.com> - 2011-08-16 22:51 -0400
        RE: Why no warnings when re-assigning builtin names? "Gerrat Rickert" <grickert@coldstorage.com> - 2011-08-17 09:30 -0400
    Re: Why no warnings when re-assigning builtin names? Chris Angelico <rosuav@gmail.com> - 2011-08-16 09:16 +0100
  Re: Why no warnings when re-assigning builtin names? Chris Torek <nospam@torek.net> - 2011-08-31 21:30 +0000
    Re: Why no warnings when re-assigning builtin names? Seebs <usenet-nospam@seebs.net> - 2011-08-31 21:57 +0000

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