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Groups > comp.lang.c > #103455

Re: C Names and Scopes

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: C Names and Scopes
Date 2017-02-08 13:41 +0100
Organization A noiseless patient Spider
Message-ID <o7f3j3$s5l$1@dont-email.me> (permalink)
References <o7duoo$vmp$1@dont-email.me> <f5ef390c-fbda-4644-8e35-6f19f6d6e6c1@googlegroups.com> <o7evtg$fk1$1@dont-email.me>

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On 08/02/17 12:39, BartC wrote:
> On 08/02/2017 11:11, Thiago Adams wrote:
>> On Wednesday, February 8, 2017 at 12:13:30 AM UTC-2, Bart wrote:
>>> I've been trying to understand this aspect, and the more I learn the
>>> more chaotic it seems compared with other languages.
>>>
>>> I've written up what I understand of it here:
>>>
>>> http://pastebin.com/UgcT0Mag
>>>
>>> If it's on totally the wrong lines then perhaps someone can point it
>>> out.
>>>
>>
>> I have the same questions on my mind and more how to implement these
>> scopes.
>>
>> I have used a multi-map. A "key" can point for more than one symbol.
>> So for instance, for function "F" I can point to the declaration and
>> also implementation and for multi-declarations of F.
>> If I have a struct X and enum X the key "X"points
>> to both and then the disambiguation can be done looking into
>> the pointed data.
> 
> I think I also have a rather strange symbol table arrangement that has
> worked successfully on /my/ languages but am trying to adapt it to C...
> 
>> For the local variables I have an stack of symbol-maps and an
>> algorithm to find the variable going up into this stack.
> 
> ... although C's block scopes are going to be a bit of a challenge. I've
> developed a scheme to deal with them efficientlu but still need to try
> it out. But it is essential that I know exactly what the capabilities
> are, including all the corner cases that even experienced C coders don't
> know exist.
> 
> (With block scopes, here is one tricky case:
> 
>    int A;        // A1
>    { A = 0;      // A1
>      int A;      // A2
>      A = 0;      // A2
>    }
> 

View the scopes like a stack.  Every new declaration is a new stack
entry - you can consider it just like entering a new block.  Any time
you need to find an identifier, you start from the top of the stack and
work down until you get a first hit.

So the code above gets parsed just as though it were:

  {
    int A;
    {
      A = 0;
      {
        int A;
        A = 0;
      }
    }
  }




> Supposed this is parsed to an AST, without doing name resolving. By
> then, I have A1 in the outer scope, and A2 in the inner one.
> 
> But if later trying to resolve the A's in either of the A=0 expressions,
> how to stop them both resolving to A2? The second 'int A' doesn't result
> in an AST node, but even if it did, it wouldn't help.
> 
> The language is forcing my hand in doing the resolving as I go along, so
> the first expression is name-resolved before the second 'int A' is
> encountered. I would rather have had the choice.)
> 
>> (
>> To implement a warning in my static analiser for hidden variable
>> (when you declare a variable with the same name of one from
>> the scope above) it's a easy task.
>> )
> 
> Your task is different. I assume the code is correct if it's legal C.
> 

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Thread

C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 02:13 +0000
  Re: C Names and Scopes David Brown <david.brown@hesbynett.no> - 2017-02-08 10:09 +0100
    Re: C Names and Scopes mark.bluemel@gmail.com - 2017-02-08 02:37 -0800
      Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 11:07 +0000
        Re: C Names and Scopes fir <profesor.fir@gmail.com> - 2017-02-08 09:03 -0800
          Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 17:19 +0000
            Re: C Names and Scopes fir <profesor.fir@gmail.com> - 2017-02-08 09:42 -0800
      Re: C Names and Scopes David Brown <david.brown@hesbynett.no> - 2017-02-08 12:08 +0100
    Re: C Names and Scopes Moai <penultimategrill@gmail.com> - 2017-02-08 19:16 -0500
      Re: C Names and Scopes David Brown <david.brown@hesbynett.no> - 2017-02-09 01:32 +0100
      Re: C Names and Scopes Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-09 08:18 -0800
      Re: C Names and Scopes Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-09 12:06 -0500
  Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 10:51 +0000
  Re: C Names and Scopes Thiago Adams <thiago.adams@gmail.com> - 2017-02-08 03:11 -0800
    Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 11:39 +0000
      Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 12:06 +0000
        Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 13:31 +0000
        Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 13:40 +0000
          Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 16:39 +0000
            Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 17:51 +0000
              Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 20:56 +0000
                Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 22:08 +0000
                Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 23:27 +0000
      Re: C Names and Scopes David Brown <david.brown@hesbynett.no> - 2017-02-08 13:41 +0100
      Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 14:32 +0000
        Re: C Names and Scopes supercat@casperkitty.com - 2017-02-08 07:28 -0800
          Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 20:12 +0000
            Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-02-08 12:38 -0800
              Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 21:54 +0000
                Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-08 22:40 +0000
  Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-09 18:48 +0000
    Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-09 19:53 +0000
      Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-02-09 12:25 -0800
        Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-09 21:27 +0000
          Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-02-09 13:57 -0800
            Re: C Names and Scopes David Brown <david.brown@hesbynett.no> - 2017-02-13 10:54 +0100
        Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-10 00:26 +0000
          Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-10 00:42 +0000
            Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-10 01:03 +0000
              Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-10 01:49 +0000
                Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-10 12:31 +0000
                Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-10 23:48 +0000
                Re: C Names and Scopes supercat@casperkitty.com - 2017-02-10 16:06 -0800
                Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-02-10 16:22 -0800
                Re: C Names and Scopes supercat@casperkitty.com - 2017-02-12 09:17 -0800
                Re: C Names and Scopes Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-15 16:26 -0800
              Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-02-09 17:56 -0800
              Re: C Names and Scopes supercat@casperkitty.com - 2017-02-10 07:42 -0800
                Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-02-10 08:44 -0800
                Re: C Names and Scopes supercat@casperkitty.com - 2017-02-10 09:25 -0800
                Re: C Names and Scopes Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-10 16:43 -0500
                Re: C Names and Scopes supercat@casperkitty.com - 2017-02-10 14:04 -0800
                Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-10 22:52 +0000
                Re: C Names and Scopes Andrey Tarasevich <andreytarasevich@hotmail.com> - 2017-02-10 15:10 -0800
        Re: C Names and Scopes Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-15 16:31 -0800
      Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-09 23:09 +0000
        Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-09 23:36 +0000
          Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-02-10 00:19 +0000
            Re: C Names and Scopes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-10 00:38 +0000
  Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-03-04 01:23 +0000
    Re: C Names and Scopes jameskuyper@verizon.net - 2017-03-03 18:23 -0800
      Re: C Names and Scopes GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-03-04 14:42 +0100
        Re: C Names and Scopes "James R. Kuyper" <jameskuyper@verizon.net> - 2017-03-04 11:02 -0500
          Re: C Names and Scopes GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-03-04 23:35 +0100
            Re: C Names and Scopes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-03-04 14:50 -0800
            Re: C Names and Scopes Richard Heathfield <rjh@cpax.org.uk> - 2017-03-05 13:39 +0000
              Re: C Names and Scopes GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-03-05 15:10 +0100
                Re: C Names and Scopes Richard Heathfield <rjh@cpax.org.uk> - 2017-03-05 14:34 +0000
                Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-03-05 19:25 -0800
              Re: C Names and Scopes raltbos@xs4all.nl (Richard Bos) - 2017-03-06 09:37 +0000
                Re: C Names and Scopes Richard Heathfield <rjh@cpax.org.uk> - 2017-03-06 10:34 +0000
                Re: C Names and Scopes James Kuyper <jameskuyper@verizon.net> - 2017-03-06 07:23 -0500
                Re: C Names and Scopes GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-03-06 14:26 +0100
    Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-03-04 11:52 -0800
      Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-03-04 20:13 +0000
        Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-03-04 20:17 +0000
        Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-03-04 12:38 -0800
        Re: C Names and Scopes jameskuyper@verizon.net - 2017-03-04 13:50 -0800
          Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-03-04 22:37 +0000
            Re: C Names and Scopes jameskuyper@verizon.net - 2017-03-04 16:15 -0800
              Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-03-05 00:31 +0000
                Re: C Names and Scopes jameskuyper@verizon.net - 2017-03-04 16:47 -0800
                Re: C Names and Scopes BartC <bc@freeuk.com> - 2017-03-05 01:42 +0000
                Re: C Names and Scopes jameskuyper@verizon.net - 2017-03-04 19:20 -0800
                Re: C Names and Scopes Keith Thompson <kst-u@mib.org> - 2017-03-05 01:40 -0800

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