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Re: Scope of identifiers

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On 06/14/17 04:02 PM, David Kleinecke wrote:
> On Tuesday, June 13, 2017 at 12:16:26 PM UTC-7, Keith Thompson wrote:
>> David Kleinecke <dkleinecke@gmail.com> writes:
>>> On Monday, June 12, 2017 at 1:19:09 PM UTC-7, Keith Thompson wrote:
>> [...]
>>>> What I proposed was to replace the current definition of "same scope"
>>>> (which is problematic because two non-identical scopes can be the "same
>>>> scope") by something like "matching scope".  (I'm open to a better
>>>> adjective than "matching".)  I think that solves the (minor) problem of
>>>> "same scope" being confusing, it doesn't add to the number of defined
>>>> terms, and it's a fairly minimal change.
>>>
>>> If one looks at the case of block scope and the old C approach
>>> one observes that all the declarations come before the statements.
>>> If one thinks of "starting" a scope extends through all the
>>> declarations then a single concept of "scope" holds.
>>>
>>> This observation doesn't help the present day situation but it does
>>> help explain how the situation cam about.
>>
>> Given:
>>
>>      {
>>          int a = 10;
>>          int b = a;
>>          int c = d; /* illegal */
>>          int d = 20;
>>          /* statements ... */
>>      }
>>
>> the initialization of c is invalid because the scope of d doesn't start
>> until the line on which it's defined.
>>
>> The lifetimes of all 4 objects begin at the same time, when
>> execution reaches the opening "{", but their scopes begin at 4
>> different locations.  All 4 scopes are the "same scope" as the
>> standard defines that phrase.  (Scope is a compile-time concept;
>> lifetime is a run-time concept.)
>>
>> [...]
>
> OK if you want to get pedantic.

This is Usenet...

> In the sense of the statements -
> all the declarations happen first. They generally are such that
> they can be freely shuffled around. C has taken advantage of the
> fact that they have to be declared in some order to introduce
> more flexibility. It can be argued that initialization is a bad
> idea and should be avoided and if there are no initializations
> the declarations can be made in any order.

I don't see why, why should the order be important?

-- 
Ian

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Thread

Scope of identifiers Steve Keller <keller@no.invalid> - 2017-06-12 18:08 +0200
  Re: Scope of identifiers "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-12 12:22 -0400
    Re: Scope of identifiers Keith Thompson <kst-u@mib.org> - 2017-06-12 09:39 -0700
  Re: Scope of identifiers Keith Thompson <kst-u@mib.org> - 2017-06-12 09:38 -0700
    Re: Scope of identifiers "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-12 14:41 -0400
      Re: Scope of identifiers Keith Thompson <kst-u@mib.org> - 2017-06-12 12:39 -0700
        Re: Scope of identifiers "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-12 15:53 -0400
          Re: Scope of identifiers Keith Thompson <kst-u@mib.org> - 2017-06-12 13:19 -0700
            Re: Scope of identifiers David Kleinecke <dkleinecke@gmail.com> - 2017-06-13 11:01 -0700
              Re: Scope of identifiers jameskuyper@verizon.net - 2017-06-13 11:25 -0700
              Re: Scope of identifiers Keith Thompson <kst-u@mib.org> - 2017-06-13 12:16 -0700
                Re: Scope of identifiers David Kleinecke <dkleinecke@gmail.com> - 2017-06-13 21:02 -0700
                Re: Scope of identifiers Ian Collins <ian-news@hotmail.com> - 2017-06-14 21:53 +1200
                Re: Scope of identifiers supercat@casperkitty.com - 2017-06-14 08:10 -0700
                Re: Scope of identifiers Keith Thompson <kst-u@mib.org> - 2017-06-14 09:19 -0700
                Re: Scope of identifiers supercat@casperkitty.com - 2017-06-14 10:14 -0700
                Re: Scope of identifiers Keith Thompson <kst-u@mib.org> - 2017-06-14 09:12 -0700
  Re: Scope of identifiers Robert Wessel <robertwessel2@yahoo.com> - 2017-06-12 13:02 -0500

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