Re: extend methods of decimal module

References	(7 earlier) <360e87d2-4daf-4222-8ebe-51f3e4d1fade@googlegroups.com> <mailman.7429.1393518292.18130.python-list@python.org> <9f7b535f-9e5d-45df-96f6-6cd8f6b4a524@googlegroups.com> <530fff58$0$11113$c3e8da3@news.astraweb.com> <f5305bab-c526-420c-8590-d73ff318ee9c@googlegroups.com>
Date	2014-02-28 16:00 +1100
Subject	Re: extend methods of decimal module
From	Chris Angelico <rosuav@gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.7454.1393563614.18130.python-list@python.org> (permalink)

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On Fri, Feb 28, 2014 at 3:41 PM, Mark H. Harris <harrismh777@gmail.com> wrote:
> So, I am thinking I need to mods...   maybe an idmath.py for interactive sessions, and then dmath.py for for running within my scientific scripts...  ??

No; the solution is to put quotes around your literals in interactive
mode, too. There's no difference between interactive and script mode,
and adding magic to interactive mode will only cause confusion.

Alternatively, there is another solution that's been posited from time
to time: Decimal literals. We currently have three forms of numeric
literal, which create three different types of object:

>>> type(1)
<class 'int'>
>>> type(.1)
<class 'float'>
>>> type(1j)
<class 'complex'>

If we had some other tag, like 'd', we could actually construct a
Decimal straight from the source code. Since source code is a string,
it'll be constructed from that string, and it'll never go via float.
Something like this:

>>> type(0.1d)
<class 'decimal.Decimal'>

which currently is a SyntaxError, so it wouldn't collide with
anything. The question is how far Python wants to bless the Decimal
type with syntax - after all, if Decimal can get a literal notation,
why can't Fraction, and why can't all sorts of other types? And that's
a huge can of worms.

ChrisA

Thread

extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-19 07:30 -0800
  Re: extend methods of decimal module Terry Reedy <tjreedy@udel.edu> - 2014-02-19 13:59 -0500
    Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-19 13:30 -0800
      Re: extend methods of decimal module Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-02-19 15:54 -0600
      Re: extend methods of decimal module Terry Reedy <tjreedy@udel.edu> - 2014-02-19 17:10 -0500
        Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 04:07 -0800
          Re: extend methods of decimal module Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2014-02-27 14:42 +0000
            Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 07:42 -0800
              Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-02-28 02:57 +1100
              Re: extend methods of decimal module Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2014-02-27 16:24 +0000
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 15:00 -0800
                Re: extend methods of decimal module Wolfgang <xpysol@gmail.com> - 2014-02-27 15:43 -0800
                Re: extend methods of decimal module Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2014-02-27 23:50 +0000
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 18:15 -0800
                Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-02-28 15:26 +1100
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 21:18 -0800
                Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-02-28 16:26 +1100
                Re: extend methods of decimal module Wolfgang Maier <wolfgang.maier@biologie.uni-freiburg.de> - 2014-02-28 08:54 +0000
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-28 10:23 -0800
                Re: extend methods of decimal module Steven D'Aprano <steve@pearwood.info> - 2014-02-28 03:15 +0000
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 20:41 -0800
                Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-02-28 16:00 +1100
                Re: extend methods of decimal module Steven D'Aprano <steve@pearwood.info> - 2014-02-28 07:34 +0000
                Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-02-28 19:52 +1100
                Re: extend methods of decimal module Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-02-28 15:11 +0000
                Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-03-01 02:36 +1100
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-28 10:34 -0800
                Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-03-01 05:37 +1100
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-28 11:26 -0800
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-28 11:39 -0800
                Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-28 12:17 -0800
          Re: extend methods of decimal module Terry Reedy <tjreedy@udel.edu> - 2014-02-27 12:07 -0500
            Re: extend methods of decimal module Anssi Saari <as@sci.fi> - 2014-03-01 08:55 +0200
              Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-03-01 16:49 -0800
          Re: extend methods of decimal module Chris Angelico <rosuav@gmail.com> - 2014-02-28 04:48 +1100
      Re: extend methods of decimal module Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-02-19 16:27 -0600
      Re: extend methods of decimal module casevh@gmail.com - 2014-02-19 21:11 -0800
        Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 02:33 -0800
          Re: extend methods of decimal module casevh@gmail.com - 2014-02-28 06:23 -0800
  Re: extend methods of decimal module Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2014-02-19 22:29 +0000
    Re: extend methods of decimal module "Mark H. Harris" <harrismh777@gmail.com> - 2014-02-27 02:37 -0800

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