Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #59225

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

Path csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed.xs4all.nl!newsfeed2.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path <python.list@tim.thechases.com>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.003
X-Spam-Evidence '*H*': 0.99; '*S*': 0.00; 'argument': 0.05; 'insert': 0.05; 'globally.': 0.07; 'suddenly': 0.07; 'assuming': 0.09; 'caller': 0.09; 'cc:addr:python-list': 0.11; 'thread': 0.14; '-tkc': 0.16; '09:00,': 0.16; 'caused.': 0.16; 'from:addr:python.list': 0.16; 'from:addr:tim.thechases.com': 0.16; 'from:name:tim chase': 0.16; 'globals': 0.16; 'mutated': 0.16; 'sys.modules': 0.16; 'wrote:': 0.18; 'module': 0.19; 'pieces': 0.19; '(the': 0.22; '>>>': 0.22; 'example': 0.22; 'cc:addr:python.org': 0.22; 'creating': 0.23; 'finally,': 0.24; 'cc:2**0': 0.24; 'cc:no real name:2**0': 0.24; 'least': 0.26; 'header:In-Reply-To:1': 0.27; 'change,': 0.30; "i'm": 0.30; 'argue': 0.31; 'constant': 0.31; 'globally': 0.31; 'idea,': 0.31; 'this.': 0.32; 'stuff': 0.32; "we're": 0.32; 'minimal': 0.33; 'johnson': 0.35; 'but': 0.35; 'charset:us-ascii': 0.36; 'should': 0.36; 'fact': 0.38; 'does': 0.39; 'bad': 0.39; 'weight': 0.39; 'sure': 0.39; 'full': 0.61; 'to:addr:gmail.com': 0.65; 'idiot': 0.84; 'protocol,': 0.84; 'received:50.22': 0.84; 'side-effects': 0.84; 'subject:Global': 0.91; 'trouble.': 0.91; 'rick': 0.93
Date Tue, 12 Nov 2013 11:45:09 -0600
From Tim Chase <python.list@tim.thechases.com>
To Rick Johnson <rantingrickjohnson@gmail.com>
Subject Re: PyMyth: Global variables are evil... WRONG!
In-Reply-To <2a325d8a-a242-4f2a-861b-9b786600f886@googlegroups.com>
References <7b97786a-2aaf-454c-8c3a-1c19d20d4345@googlegroups.com> <d1bb2f3b-d5d7-4336-8984-3871ecf5a16e@googlegroups.com> <d0b7995e-72c3-4c6d-bac3-d9f90bc91b39@googlegroups.com> <4bef88d0-d3eb-42e5-ac8e-288c629c528e@googlegroups.com> <2a325d8a-a242-4f2a-861b-9b786600f886@googlegroups.com>
X-Mailer Claws Mail 3.8.1 (GTK+ 2.24.10; x86_64-pc-linux-gnu)
Mime-Version 1.0
Content-Type text/plain; charset=US-ASCII
Content-Transfer-Encoding 7bit
X-AntiAbuse This header was added to track abuse, please include it with any abuse report
X-AntiAbuse Primary Hostname - boston.accountservergroup.com
X-AntiAbuse Original Domain - python.org
X-AntiAbuse Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse Sender Address Domain - tim.thechases.com
X-Get-Message-Sender-Via boston.accountservergroup.com: authenticated_id: tim@thechases.com
Cc python-list@python.org
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.15
Precedence list
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <https://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list/>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <https://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups comp.lang.python
Message-ID <mailman.2484.1384278220.18130.python-list@python.org> (permalink)
Lines 39
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1384278220 news.xs4all.nl 15956 [2001:888:2000:d::a6]:32841
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:59225

Show key headers only | View raw

On 2013-11-12 09:00, Rick Johnson wrote:
> Because the constant PI should never change. Sure we can
> argue about granularity of PI, but that argument has no
> weight on the fact that PI should be a constant.
> 
> By placing PI in the module "math", we are creating a pseudo
> interface. We (the creators) are "assuming" that PI will be a
> constant and never change, and the caller is assuming that
> pi will remain static,  but not only can it be mutated, it
> can be mutated globally.

But the module-scoping of "globals" is perfectly valid:

 >>> print(math.PI)
 3.1415926535897932
 >>> print(Magnum.PI)
 "Tom Selleck"

As an example from the stdlib of setting globals via a protocol,
locale.setlocale() does exactly this.  So I'm not sure why you have
your knickers in a knot.  Module-level items can be accessed
globally (though often a bad idea, or at least you have to beware of
side-effects where other things might break), and if you don't like
the "modules are not objects", someone in this thread already showed
you that you can insert objects/classes into the sys.modules and get
full getter/setter functionality with minimal trouble.

Finally, we're all (mostly) consenting adults here.  If I want to be
an idiot and

  math.PI = 3.14

and suddenly stuff breaks, I get to keep all the pieces my breakage
caused.

-tkc

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

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

csiph-web