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Re: Lexical Variables In C Loops (As Compared To Perl Loops)

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On 03/22/2015 07:39 PM, Keith Thompson wrote:
> James Kuyper <jameskuyper@verizon.net> writes:
>> On 03/21/2015 04:01 PM, Philip Lantz wrote:
> [...]
>>> The difference between C and Perl is that in C the lifetime of the 
>>> variable always ends at the end of each iteration of the loop, whereas 
>>> in Perl the lifetime of the variable may extend beyond the end of the 
>>> iteration of the loop in which it was allocated (and does, in this 
>>> example).
>>
>> Can you refer to $var after the end of the loop? If only the memory
>> persists, rather than access to that memory through the variable name,
>> then you can't properly say that the variable persists. If you can
>> access the memory through $var after the loop, which of the ten
>> different addresses given does it refer to?
> 
> What exactly do you mean by the word "variable"? ...

A named object. I can cite support for that definition from the C++
standard (3p6), though that definition is far more complex than mine.
However, I'll freely admit that the C standard provides no such
definition. It's just my personal definition, though I did check many
uses of the term as a noun in the C standard, and they all seemed
consistent with that definition (the C standard uses "variable" as an
adjective far more often than as a noun, which makes the search difficult).

> ...  The C standard doesn't
> define it, so there's no definitive answer.  The way I use it, the word
> "variable" is nearly synonymous with "object", except that not all
> objects are variables.  In that sense, I'd say that $var can persist
> outside the loop, even if it's not visible by that name.

As a "named object", it ceases to qualify as a variable when the
connection to it's name is no longer usable.
-- 
James Kuyper

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Lexical Variables In C Loops (As Compared To Perl Loops) Robbie Hatley <see.my.sig@for.my.address> - 2015-03-21 00:52 -0700
  Re: Lexical Variables In C Loops (As Compared To Perl Loops) Richard Heathfield <rjh@cpax.org.uk> - 2015-03-21 08:28 +0000
    Re: Lexical Variables In C Loops (As Compared To Perl Loops) Robbie Hatley <see.my.sig@for.my.address> - 2015-03-26 20:57 -0700
  Re: Lexical Variables In C Loops (As Compared To Perl Loops) Keith Thompson <kst-u@mib.org> - 2015-03-21 01:29 -0700
    Re: Lexical Variables In C Loops (As Compared To Perl Loops) Robbie Hatley <see.my.sig@for.my.address> - 2015-03-26 21:01 -0700
  Lexical Variables In C Loops (As Compared To Perl Loops) asetofsymbols@gmail.com - 2015-03-21 01:40 -0700
  Re: Lexical Variables In C Loops (As Compared To Perl Loops) jt@toerring.de (Jens Thoms Toerring) - 2015-03-21 08:43 +0000
    Re: Lexical Variables In C Loops (As Compared To Perl Loops) Robbie Hatley <see.my.sig@for.my.address> - 2015-03-26 20:58 -0700
      Re: Lexical Variables In C Loops (As Compared To Perl Loops) Richard Heathfield <rjh@cpax.org.uk> - 2015-03-27 06:12 +0000
      Re: Lexical Variables In C Loops (As Compared To Perl Loops) Keith Thompson <kst-u@mib.org> - 2015-03-26 23:32 -0700
  Re: Lexical Variables In C Loops (As Compared To Perl Loops) Bartc <bc@freeuk.com> - 2015-03-21 10:54 +0000
    Re: Lexical Variables In C Loops (As Compared To Perl Loops) Keith Thompson <kst-u@mib.org> - 2015-03-21 13:54 -0700
    Re: Lexical Variables In C Loops (As Compared To Perl Loops) Robbie Hatley <see.my.sig@for.my.address> - 2015-03-26 21:24 -0700
      Re: Lexical Variables In C Loops (As Compared To Perl Loops) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-03-27 20:35 +0000
      Re: Lexical Variables In C Loops (As Compared To Perl Loops) Bartc <bc@freeuk.com> - 2015-03-27 21:24 +0000
        Re: Lexical Variables In C Loops (As Compared To Perl Loops) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-03-28 00:03 +0000
          Re: Lexical Variables In C Loops (As Compared To Perl Loops) Bartc <bc@freeuk.com> - 2015-03-28 10:00 +0000
        Re: Lexical Variables In C Loops (As Compared To Perl Loops) Stephen Sprunk <stephen@sprunk.org> - 2015-03-28 18:14 -0500
  Re: Lexical Variables In C Loops (As Compared To Perl Loops) Kaz Kylheku <kaz@kylheku.com> - 2015-03-21 14:39 +0000
  Re: Lexical Variables In C Loops (As Compared To Perl Loops) fir <profesor.fir@gmail.com> - 2015-03-21 09:40 -0700
  Re: Lexical Variables In C Loops (As Compared To Perl Loops) James Kuyper <jameskuyper@verizon.net> - 2015-03-21 12:43 -0400
    Re: Lexical Variables In C Loops (As Compared To Perl Loops) Philip Lantz <prl@canterey.us> - 2015-03-21 13:01 -0700
      Re: Lexical Variables In C Loops (As Compared To Perl Loops) James Kuyper <jameskuyper@verizon.net> - 2015-03-22 18:47 -0400
        Re: Lexical Variables In C Loops (As Compared To Perl Loops) Keith Thompson <kst-u@mib.org> - 2015-03-22 16:39 -0700
          Re: Lexical Variables In C Loops (As Compared To Perl Loops) James Kuyper <jameskuyper@verizon.net> - 2015-03-22 20:08 -0400
            Re: Lexical Variables In C Loops (As Compared To Perl Loops) Robbie Hatley <see.my.sig@for.my.address> - 2015-03-26 22:36 -0700
              Re: Lexical Variables In C Loops (As Compared To Perl Loops) Keith Thompson <kst-u@mib.org> - 2015-03-26 23:40 -0700
        Re: Lexical Variables In C Loops (As Compared To Perl Loops) Robbie Hatley <see.my.sig@for.my.address> - 2015-03-26 22:26 -0700
          Re: Lexical Variables In C Loops (As Compared To Perl Loops) Keith Thompson <kst-u@mib.org> - 2015-03-26 23:38 -0700

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