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Re: Method Chaining

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From Michael Torrie <torriem@gmail.com>
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Subject Re: Method Chaining
Date Sun, 19 Jun 2016 09:14:21 -0600
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On 06/19/2016 09:01 AM, Ethan Furman wrote:
> On 06/19/2016 04:56 AM, Joonas Liik wrote:
>> On 18 June 2016 at 23:47, Ethan Furman wrote:
>>> On 06/18/2016 07:05 AM, Joonas Liik wrote:
> 
>>>> 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?
>>
>> What if ob_b does not have attribute attr_c but ob_a does?
> 
> Good question.  I would say that _only_ the innermost with object is 
> searched, and if it doesn't have the requested attribute an 
> AttributeError is raised.  Otherwise, as you say, it could be a 
> nightmare to maintain.

But that wouldn't work either because it would make it impossible to
*set* attributes on an object.

If ob_a had attr_c but object ob_b did not, should it set the attribute
on ob_b or overwrite the attribute on ob_a?

Python's dynamic nature just doesn't lend itself to this kind of ambiguity.

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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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