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Re: PyMyth: Global variables are evil... WRONG!

References <7b97786a-2aaf-454c-8c3a-1c19d20d4345@googlegroups.com> <deh8la-8p4.ln1@ozzie.tundraware.com> <82561733-d131-45de-ab10-c847f1960dc4@googlegroups.com>
Date 2013-11-12 16:02 +1100
Subject Re: PyMyth: Global variables are evil... WRONG!
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.2427.1384232570.18130.python-list@python.org> (permalink)

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On Tue, Nov 12, 2013 at 3:46 PM, Rick Johnson
<rantingrickjohnson@gmail.com> wrote:
> But python modules can't be interfaces because interfaces
> should protect internal data, prevent external forces from
> meddling with internal state (EXCEPT via the rules of a
> predefined "contract"), hide dirty details from the caller,
> and have clearly defined access points.
>
>   BUT PYTHON MODULES DON'T FOLLOW THIS DESIGN PATTERN!
>
> No, Python modules can be poked, prodded, and violated by
> any pervert who can spell the word "import".

And C++ objects can be poked by anyone who can do a pointer cast. And
Java objects by anyone who notices that 'const' checks don't apply to
byte-code. In fact, the only language I can think of that actually
"prevent[s] external forces from meddling with internal state" is
HQ9++, which follows the very best principles of data hiding.

ChrisA

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Thread

PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-11 18:06 -0800
  Re: PyMyth: Global variables are evil... WRONG! Tim Daneliuk <tundra@tundraware.com> - 2013-11-11 20:47 -0600
    Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-11 20:46 -0800
      Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-12 16:02 +1100
      Re: PyMyth: Global variables are evil... WRONG! Ricardo Aráoz <ricaraoz@gmail.com> - 2013-11-12 07:15 -0300
      Re: PyMyth: Global variables are evil... WRONG! Tim Chase <python.list@tim.thechases.com> - 2013-11-12 05:32 -0600
      Re: PyMyth: Global variables are evil... WRONG! Terry Reedy <tjreedy@udel.edu> - 2013-11-12 20:20 -0500
      Re: PyMyth: Global variables are evil... WRONG! Tim Daneliuk <tundra@tundraware.com> - 2013-11-13 18:17 -0600
        Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-13 18:25 -0800
  Re: PyMyth: Global variables are evil... WRONG! jongiddy <jongiddy@gmail.com> - 2013-11-12 06:12 -0800
    Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-12 07:05 -0800
      Re: PyMyth: Global variables are evil... WRONG! jongiddy <jongiddy@gmail.com> - 2013-11-12 07:33 -0800
        Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-12 09:00 -0800
          Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-12 09:42 -0800
          Re: PyMyth: Global variables are evil... WRONG! Tim Chase <python.list@tim.thechases.com> - 2013-11-12 11:45 -0600
          Re: PyMyth: Global variables are evil... WRONG! jongiddy <jongiddy@gmail.com> - 2013-11-12 14:41 -0800
            Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-12 18:45 -0800
              Re: PyMyth: Global variables are evil... WRONG! Tim Chase <python.list@tim.thechases.com> - 2013-11-12 21:22 -0600
              Re: PyMyth: Global variables are evil... WRONG! Andrew Cooper <root@127.0.0.1> - 2013-11-13 22:00 +0000
                Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-13 18:16 -0800
  Re: PyMyth: Global variables are evil... WRONG! Alister <alister.ware@ntlworld.com> - 2013-11-12 14:32 +0000
    Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-13 02:22 +1100
  Re: PyMyth: Global variables are evil... WRONG! "Rhodri James" <rhodri@wildebst.demon.co.uk> - 2013-11-13 23:42 +0000
    Re: PyMyth: Global variables are evil... WRONG! Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-11-13 23:57 +0000
    Re: PyMyth: Global variables are evil... WRONG! Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-14 01:09 +0000
      Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-13 19:22 -0800
        Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-14 14:29 +1100
          Re: PyMyth: Global variables are evil... WRONG! Roy Smith <roy@panix.com> - 2013-11-13 23:33 -0500
            Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-13 20:40 -0800
            Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-14 15:53 +1100
            Re: PyMyth: Global variables are evil... WRONG! Steven D'Aprano <steve@pearwood.info> - 2013-11-14 06:25 +0000
          Re: PyMyth: Global variables are evil... WRONG! unknown <unknown@unknown.com> - 2013-11-14 09:41 +0000
    Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-13 18:10 -0800
      Re: PyMyth: Global variables are evil... WRONG! Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-14 02:45 +0000
        Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-13 19:45 -0800
          Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-13 20:01 -0800
          Re: PyMyth: Global variables are evil... WRONG! Steven D'Aprano <steve@pearwood.info> - 2013-11-14 05:50 +0000
            Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-14 09:26 -0800
              Re: PyMyth: Global variables are evil... WRONG! Joel Goldstick <joel.goldstick@gmail.com> - 2013-11-14 12:37 -0500
              Re: PyMyth: Global variables are evil... WRONG! Ethan Furman <ethan@stoneleaf.us> - 2013-11-14 09:56 -0800
                Re: PyMyth: Global variables are evil... WRONG! Alister <alister.ware@ntlworld.com> - 2013-11-14 20:12 +0000
                Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-15 09:43 +1100
              Re: PyMyth: Global variables are evil... WRONG! Joel Goldstick <joel.goldstick@gmail.com> - 2013-11-14 13:43 -0500
              Re: PyMyth: Global variables are evil... WRONG! Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-11-14 19:04 +0000
              Re: PyMyth: Global variables are evil... WRONG! Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-15 08:19 +0000
                Re: PyMyth: Global variables are evil... WRONG! Tim Daneliuk <tundra@tundraware.com> - 2013-11-15 09:26 -0600
                Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-16 02:42 +1100
                Re: PyMyth: Global variables are evil... WRONG! Tim Daneliuk <tundra@tundraware.com> - 2013-11-15 17:33 -0600
                Re: PyMyth: Global variables are evil... WRONG! Tim Daneliuk <tundra@tundraware.com> - 2013-11-15 17:33 -0600
                Re: PyMyth: Global variables are evil... WRONG! Rick Johnson <rantingrickjohnson@gmail.com> - 2013-11-15 20:01 -0800
                Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-16 15:19 +1100
                Re: PyMyth: Global variables are evil... WRONG! Chris Angelico <rosuav@gmail.com> - 2013-11-16 15:14 +1100

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