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Groups > comp.lang.python > #110138

Re: Method Chaining

From Joonas Liik <liik.joonas@gmail.com>
Newsgroups comp.lang.python
Subject Re: Method Chaining
Date 2016-06-19 14:56 +0300
Message-ID <mailman.133.1466337413.2288.python-list@python.org> (permalink)
References (6 earlier) <2dffea93-3dbd-4d04-93ed-6e02e3dd8660@googlegroups.com> <m1inx6wvni.fsf@iKarel.lan> <CAB1GNpRLRNDQ3f4a7MBeBXZqO+9ypR-uEEGW85arOwEimsQsdQ@mail.gmail.com> <5765B36F.5010506@stoneleaf.us> <CAB1GNpSStN+eQfwyMk02QbaRQscn5DSK-FwNozXE+2Gf0EYPAA@mail.gmail.com>

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On 18 June 2016 at 23:47, Ethan Furman <ethan@stoneleaf.us> wrote:
> On 06/18/2016 07:05 AM, Joonas Liik wrote:
>>
>> On 18 June 2016 at 15:04, Pete Forman wrote:
>
>
>>> with obj:
>>>      .a = 1                # equivalent to obj.a = 1
>>>      .total = .total + 1   # obj.total = obj.total + 1
>>
>>
>> the leading dot does not resolve the ambiguity that arises from:
>>
>> with ob_a:
>>      with ob_b:
>>          .attr_c = 42 # which object are we modifying right now?
>
>
> The innermost one.  Why would it be anything else?
>
> --
> ~Ethan~
>
> --
> https://mail.python.org/mailman/listinfo/python-list

What if ob_b does not have attribute attr_c but ob_a does?

This may be simple for a computer to solve - try looking it up on ob_b
and fall back to ob_a if ob_b has no such attr..  but it is hard(er)
to reason about for a human. You need to know about the inner
structure of ob_b. not an issue for the person who writes it at first
(unless 2 months have passed ) but a real pain if you are seeing that
bit of code for the first time or are not intimately familiar with
what ob_b is.

Not unsolvable ofc, but makes it easier for obscure bugs to hide.

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Thread

Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-16 19:02 -0700
  Re: Method Chaining Steven D'Aprano <steve@pearwood.info> - 2016-06-17 12:39 +1000
  Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 04:23 +0000
    Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-16 21:37 -0700
      Re: Method Chaining Ned Batchelder <ned@nedbatchelder.com> - 2016-06-17 01:13 -0700
        Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 01:38 -0700
          Re: Method Chaining Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-17 11:45 +0300
        Re: Method Chaining Steven D'Aprano <steve@pearwood.info> - 2016-06-17 19:28 +1000
          Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 13:34 +0000
            Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 15:26 -0700
              Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 22:45 +0000
              Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 23:10 +0000
          Re: Method Chaining Rustom Mody <rustompmody@gmail.com> - 2016-06-17 09:48 -0700
            Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 15:25 -0700
            Re: Method Chaining Pete Forman <petef4+usenet@gmail.com> - 2016-06-18 13:04 +0100
              Re: Method Chaining Joonas Liik <liik.joonas@gmail.com> - 2016-06-18 17:05 +0300
                Re: Method Chaining Pete Forman <petef4+usenet@gmail.com> - 2016-06-18 16:42 +0100
              Re: Method Chaining Rustom Mody <rustompmody@gmail.com> - 2016-06-18 08:35 -0700
                Re: Method Chaining Pete Forman <petef4+usenet@gmail.com> - 2016-06-19 11:16 +0100
              Re: Method Chaining Ethan Furman <ethan@stoneleaf.us> - 2016-06-18 13:47 -0700
              Re: Method Chaining Joonas Liik <liik.joonas@gmail.com> - 2016-06-19 14:56 +0300
              Re: Method Chaining Ethan Furman <ethan@stoneleaf.us> - 2016-06-19 08:01 -0700
              Re: Method Chaining Michael Torrie <torriem@gmail.com> - 2016-06-19 09:14 -0600
              Re: Method Chaining Ethan Furman <ethan@stoneleaf.us> - 2016-06-19 08:56 -0700
                Re: Method Chaining Rustom Mody <rustompmody@gmail.com> - 2016-06-19 09:03 -0700
        Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 15:22 -0700
          Re: Method Chaining Ned Batchelder <ned@nedbatchelder.com> - 2016-06-17 17:02 -0700

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