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Re: The type/object distinction and possible synthesis of OOP and imperative programming languages

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Date Wed, 17 Apr 2013 14:04:48 +0200
From Antoon Pardon <antoon.pardon@rece.vub.ac.be>
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Subject Re: The type/object distinction and possible synthesis of OOP and imperative programming languages
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Op 16-04-13 18:49, Terry Jan Reedy schreef:
> On 4/16/2013 5:07 AM, Antoon Pardon wrote:
>> Op 16-04-13 05:17, Terry Jan Reedy schreef:
>>
>>> I will keep the above in mind if I write or review a patch. here are 4
>>> non-subclassable builtin classes. Two are already documented. Bool in
>>> one, forget which other. I believe it was recently decided to leave
>>> the other two as is given the absence of any practical use case.
>>
>> Why should there be a practical use case here?
>
> As a practical matter, the change is non-trivial. Someone has to be
> motivated to write the patch to enable subclassing, write tests, and
> consider the effect on internal C uses of slice and stdlib Python used
> of slice (type() versus isinstance).
I see. It seems I have underestimated the work involved.

>> I once had an idea of a slice-like class that I would have liked to
>> experiment with.
>
> Did the idea actually require that instances *be* a slice rather than
> *wrap* a slice? 

As far as I remember I wanted my slice object usable to slice lists
with. But python doesn't allow duck typing when you use your object to
"index" a list. No matter how much your object resembles a slice, when
you actualy try to use it to get a slice of a list, python throw a
TypeError with the message "object cannot be interpreted as an index".
This in combination with slice not being subclassable effectively killed
the idea.

As I already said I don't know if the idea would have turned up
something usefull. The following years I never had the feeling how great
it would have been should I have been able to pursue this idea. I just
thought it was a pity I was so thoroughly stopped at the time.

-- 
Antoon Pardon

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Thread

The type/object distinction and possible synthesis of OOP and imperative programming languages Mark Janssen <dreamingforward@gmail.com> - 2013-04-14 20:48 -0700
  Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-15 10:11 +0000
    Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-04-15 19:43 +0200
      Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-16 02:15 +0000
    Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Dave Angel <davea@davea.name> - 2013-04-15 17:13 -0400
      Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Rotwang <sg552@hotmail.co.uk> - 2013-04-15 23:12 +0100
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Chris Angelico <rosuav@gmail.com> - 2013-04-16 08:32 +1000
          Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Rotwang <sg552@hotmail.co.uk> - 2013-04-15 23:54 +0100
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Mark Janssen <dreamingforward@gmail.com> - 2013-04-16 15:38 -0700
          Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-17 06:40 +0000
            Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Chris Angelico <rosuav@gmail.com> - 2013-04-17 16:56 +1000
            Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Chris Rebert <clp2@rebertia.com> - 2013-04-17 00:16 -0700
            Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-04-17 18:40 -0400
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Ian Kelly <ian.g.kelly@gmail.com> - 2013-04-16 17:14 -0600
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Michael Torrie <torriem@gmail.com> - 2013-04-18 10:37 -0600
          Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Neil Cerutti <neilc@norwich.edu> - 2013-04-18 17:57 +0000
          Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-19 01:00 +0000
            Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Roy Smith <roy@panix.com> - 2013-04-18 21:08 -0400
              Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Mark Janssen <dreamingforward@gmail.com> - 2013-04-18 18:24 -0700
              Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Ned Batchelder <ned@nedbatchelder.com> - 2013-04-18 22:10 -0400
              Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Mark Janssen <dreamingforward@gmail.com> - 2013-04-18 19:30 -0700
                Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-19 03:38 +0000
              Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Ned Batchelder <ned@nedbatchelder.com> - 2013-04-18 22:39 -0400
              Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Mark Janssen <dreamingforward@gmail.com> - 2013-05-01 13:32 -0700
                Re: The type/object distinction and possible synthesis of OOP and imperative programming languages alex23 <wuwei23@gmail.com> - 2013-05-01 18:13 -0700
    Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Terry Jan Reedy <tjreedy@udel.edu> - 2013-04-15 20:52 -0400
      Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-16 02:32 +0000
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Terry Jan Reedy <tjreedy@udel.edu> - 2013-04-15 23:17 -0400
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Ian Kelly <ian.g.kelly@gmail.com> - 2013-04-15 22:46 -0600
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages rusi <rustompmody@gmail.com> - 2013-04-15 21:56 -0700
          Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-16 05:59 +0000
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Serhiy Storchaka <storchaka@gmail.com> - 2013-04-16 11:25 +0300
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-04-16 11:07 +0200
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Terry Jan Reedy <tjreedy@udel.edu> - 2013-04-16 12:49 -0400
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Ethan Furman <ethan@stoneleaf.us> - 2013-04-16 10:29 -0700
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Terry Jan Reedy <tjreedy@udel.edu> - 2013-04-16 14:29 -0400
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Ian Kelly <ian.g.kelly@gmail.com> - 2013-04-16 12:22 -0600
        Re: The type/object distinction and possible synthesis of OOP and imperative programming languages Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-04-17 14:04 +0200
  Re: The type/object distinction and possible synthesis of OOP and imperative programming languages 88888 Dihedral <dihedral88888@googlemail.com> - 2013-04-15 23:54 -0700
  Re: The type/object distinction and possible synthesis of OOP and imperative programming languages 88888 Dihedral <dihedral88888@googlemail.com> - 2013-04-15 23:54 -0700
  Re: The type/object distinction and possible synthesis of OOP and imperative programming languages rusi <rustompmody@gmail.com> - 2013-04-21 08:44 -0700

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