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Groups > comp.lang.python > #72905

Re: OT: This Swift thing

From Christian Gollwitzer <auriocus@gmx.de>
Newsgroups comp.lang.python, comp.lang.c++
Subject Re: OT: This Swift thing
Followup-To comp.lang.c++
Date 2014-06-07 09:30 +0200
Organization A noiseless patient Spider
Message-ID <lmuf2p$4fv$1@dont-email.me> (permalink)
References (2 earlier) <mailman.10735.1401977435.18130.python-list@python.org> <87tx7zi0i1.fsf@dpt-info.u-strasbg.fr> <lmqn53$4ei$1@ger.gmane.org> <mailman.10772.1402004202.18130.python-list@python.org> <87sininv2y.fsf@dpt-info.u-strasbg.fr>

Cross-posted to 2 groups.

Followups directed to: comp.lang.c++

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Am 06.06.14 13:20, schrieb Alain Ketterlin:
> Chris Angelico <rosuav@gmail.com> writes:
>> It's impossible to accidentally call a base class's method when you
>> ought to have called the overriding method in the subclass, which is a
>> risk in C++ [2].
>
> I don't how this can happen in C++, unless you actually have an instance
> of the base class. Anyway, I didn't mention C++.

A special, but important case of this is inside the constructor. Until 
you exit the constructor, C++ treats the object as not fully 
constructed, and if you call a virtual method there, it calls the method 
of the base class.

http://www.parashift.com/c++-faq/calling-virtuals-from-ctors.html

The answer is, of course, to create a *separate* init function in 
addition to the constructor and to require the user of the class to call 
it after the constructor, or to hide the real constructor away and 
require the user to call a factory function instead.

I love C++.
(seriously, but not /that/ part)

	Christian

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Thread

OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-03 17:28 +0000
  Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 10:14 +0200
    Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-05 18:38 +1000
      Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 11:42 +0200
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-05 22:48 +1000
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 22:27 +0200
            Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-05 22:28 +0100
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:03 +0000
              Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:21 +0200
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-07 01:54 +0000
                Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-07 10:20 +0200
                Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-07 09:32 +0100
                Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-07 11:54 +0200
                Re: OT: This Swift thing Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-06-15 10:55 +0200
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 08:52 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 11:13 -0400
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 11:54 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 17:10 -0400
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-07 23:32 +0000
            Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-06 00:41 +0100
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-06 01:54 +0200
              Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-05 20:13 -0400
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-06 02:35 +0200
              Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-06 05:45 +0000
              Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:39 +0200
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-07 01:54 +0000
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-06 02:03 +0200
    Re: OT: This Swift thing wxjmfauth@gmail.com - 2014-06-05 02:09 -0700
    Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 16:10 +0200
      Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 22:07 +0200
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 06:18 +1000
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 23:12 +0200
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:02 +0000
        Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-05 22:23 +0100
          Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-06 00:53 +0300
            Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-05 23:13 +0100
              Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-06 02:52 +0000
            Re: OT: This Swift thing Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-06-15 11:33 +0200
              Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-15 16:10 +0300
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 07:36 +1000
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:20 +0200
            Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 22:23 +1000
            Re: OT: This Swift thing Christian Gollwitzer <auriocus@gmx.de> - 2014-06-07 09:30 +0200
        Re: OT: This Swift thing Terry Reedy <tjreedy@udel.edu> - 2014-06-05 18:18 -0400
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:11 +0200
            Re: OT: This Swift thing Terry Reedy <tjreedy@udel.edu> - 2014-06-06 13:06 -0400
            Re: OT: This Swift thing alex23 <wuwei23@gmail.com> - 2014-06-10 15:32 +1000
        Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:02 +0000
        Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-05 23:08 +0000
        Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:08 +0000
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 09:21 +1000
          Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-06 03:16 +0000
            Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 13:27 +1000
    Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-05 08:33 -0600
    Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 01:44 +1000
    Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 18:09 +0200
    Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-05 11:18 -0600
      Re: OT: This Swift thing Mark H Harris <harrismh777@gmail.com> - 2014-06-05 13:49 -0500
    Re: OT: This Swift thing Travis Griggs <travisgriggs@gmail.com> - 2014-06-05 23:28 -0700
      Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 10:25 +0200
    Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-06 20:41 -0600
      Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-07 04:57 +0000
        Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 11:23 -0400
          Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 11:51 -0400
            Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-07 19:18 +0300
              Re: OT: This Swift thing MRAB <python@mrabarnett.plus.com> - 2014-06-08 15:10 +0100
        Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-07 11:37 -0600
          Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 14:11 -0400
            Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-07 13:00 -0600
              Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 15:11 -0400
            Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 17:59 -0400
              Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-08 13:25 +1200
            Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-07 23:38 +0000
              Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 20:09 -0400
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-08 10:37 +1000
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-08 03:50 +0000
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-08 10:51 -0400
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-08 11:21 -0400
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-08 12:09 -0400
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-08 13:14 -0400
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-09 03:25 +1000
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-08 18:09 +0000
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-09 04:16 +1000
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-09 01:44 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 19:24 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-09 04:20 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 23:32 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-09 09:27 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-09 04:51 -0700
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-11 19:41 +1200
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-11 13:44 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-11 08:28 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-12 02:08 +0000
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-12 12:16 +1000
                Re: OT: This Swift thing Steven D'Aprano <steve@pearwood.info> - 2014-06-12 09:06 +0000
                Re: OT: This Swift thing alister <alister.nospam.ware@ntlworld.com> - 2014-06-12 09:34 +0000
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-12 23:32 +1200
                Re: OT: This Swift thing Anssi Saari <as@sci.fi> - 2014-06-16 13:57 +0300
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-17 10:12 +1200
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-17 08:34 +1000
                Re: OT: This Swift thing alister <alister.nospam.ware@ntlworld.com> - 2014-06-17 11:16 +0000
                Re: OT: This Swift thing Bob Martin <bob.martin@excite.com> - 2014-06-18 07:41 +0100
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-12 05:54 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-12 17:04 +0000
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-13 03:18 +1000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-12 18:59 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-13 03:26 +0000
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-12 14:43 -0400
                Re: OT: This Swift thing albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-06-27 23:21 +0000
                Re: OT: This Swift thing Joshua Landau <joshua@landau.ws> - 2014-06-15 02:51 +0100
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-15 03:33 +0000
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-09 10:11 -0400
                Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-09 17:27 +0300
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-11 18:56 +1200
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-09 09:14 -0400
                Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-09 07:56 -0600
                Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-09 17:30 +0300
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 19:35 -0700
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-09 12:23 +1000
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-11 19:50 +1200
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-11 12:34 +0000
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-11 08:48 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-11 20:17 -0400
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-12 01:25 +0000
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-12 14:11 +1200
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-11 23:06 -0400
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-13 08:55 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-09 21:51 -0400
                Re: OT: This Swift thing Carlos Anselmo Dias <carlos@premium-sponsor.com> - 2014-06-08 18:56 +0100
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-08 23:34 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 19:32 -0700
          Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-08 13:09 +1200

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