Re: Mechanism to generate annotated "error codes"

From	Kaz Kylheku <kaz@kylheku.com>
Newsgroups	comp.lang.c
Subject	Re: Mechanism to generate annotated "error codes"
Date	2012-03-03 14:52 +0000
Organization	Aioe.org NNTP Server
Message-ID	<20120303062257.175@kylheku.com> (permalink)
References	<jiojq3$3cm$1@speranza.aioe.org> <error-codes-20120302005428-Supersedes@ram.dialup.fu-berlin.de> <jipsv0$rkd$1@speranza.aioe.org> <lnr4xb71y6.fsf@nuthaus.mib.org> <jisrsd$b8j$1@dont-email.me>

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On 2012-03-03, BartC <bc@freeuk.com> wrote:
> "Keith Thompson" <kst-u@mib.org> wrote in message 
> news:lnr4xb71y6.fsf@nuthaus.mib.org...
>> Don Y <this@isnotme.com> writes:
>> [...]
>>> You need to maintain this "by hand".  There is nothing that
>>> prevents you from:
>>>    #define YES  (2)
>>>    #define NO   (2)
>>>
>>> Nor:
>>>    #define YES (2)
>>>    ...
>>>    #define ABSOLUTELY  (27)
>>> (assuming yes and absolutely are synonyms)
>> [...]
>>
>> A minor point: parenthesizing macro definitions is a good habit, but
>> it's not necessary when the macro expands to a single token.  This:
>>
>>    #define ABSOLUTELY 27
>>
>> is just as safe as
>>
>>    #define ABSOLUTELY (27)
>
> What happens when someone experiments with the value 27 by trying this:
>
>     #define ABSOLUTELY 27+1

That same someone might experiment with (27) this way:

   #define ABSOLUTELY (27)+1

You can't possibly be suggesting that when you're coding, you're not only
responsible for what you're actually writing, but also for all possible
careless or clueless mutations of it by someone else?

If you're thinking that this someone is actually yourself, later, then change
the habits of that someone. Don't experiment with a constant 27 by changing it
to 27+1, but just replace it with 28. Always use some kind of version control
which can tell you at any time where your experimental changes are, so
you don't need to use +1 as a flag denoting an experimental change, or
to remind you of what the stock value is.

Secondly, acquire a smarter habit: that of ensuring that every macro
definition you touch, which produces an expression, produces a primary
expression. 27 is already a primary expression, so needs nothing.
21+1 is not a primary expression, and so it needs parentheses, or a
rewrite to 28.

Even the habit of "always add parentheses" is still conditional on something!
Because the dummy who does this will surely not add parentheses every time an
edit is made, like an automaton. E.g.

  #define ABSOLUTELY ((27)+1) /* experiment */

  #define ABSOLUTELY (((27)+1)+1) /* another experiment */

Even the always-parenthesizing dummy still recognizes that the expression is
already parenthesized (and that experiments can go into the parentheses).

If your habit is conditional anyway, you might as well choose a smart condition
for it: "if expr not already primary, make primary".

Thread

Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 12:48 -0700
  Re: Mechanism to generate annotated "error codes" Willem <willem@toad.stack.nl> - 2012-03-01 21:29 +0000
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 16:53 -0700
  Re: Mechanism to generate annotated "error codes" William Ahern <william@wilbur.25thandClement.com> - 2012-03-01 14:13 -0800
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 22:07 -0700
  Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-01 17:53 -0500
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 23:05 -0700
      Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-02 01:50 -0500
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 00:43 -0700
          Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-03 17:58 -0500
            Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-04 03:16 -0500
              Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 13:47 -0700
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 13:45 -0700
              Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-04 18:37 -0500
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 22:12 -0700
                Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-08 01:41 -0500
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-09 14:34 -0700
  Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 00:30 -0700
    Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-02 02:05 -0800
      Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-02 10:47 +0000
      Re: Mechanism to generate annotated "error codes" gazelle@shell.xmission.com (Kenny McCormack) - 2012-03-02 14:18 +0000
      Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 10:46 -0700
        Re: Mechanism to generate annotated "error codes" James Kuyper <jameskuyper@verizon.net> - 2012-03-02 14:08 -0500
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 12:38 -0700
        Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-02 22:57 +0000
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 17:14 -0700
            Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-03 02:25 +0000
            Re: Mechanism to generate annotated "error codes" James Kuyper <jameskuyper@verizon.net> - 2012-03-03 06:10 -0500
              Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-03 16:12 -0500
        Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-03 04:04 -0800
          Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-03 15:05 +0000
            Re: Mechanism to generate annotated "error codes" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-03 16:25 +0000
          Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-03 16:26 -0500
            Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-03 13:40 -0800
      Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-03 12:03 +1300
        Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-02 15:45 -0800
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 17:18 -0700
      Re: Mechanism to generate annotated "error codes" blp@cs.stanford.edu (Ben Pfaff) - 2012-03-02 15:08 -0800
      Re: Mechanism to generate annotated "error codes" "BartC" <bc@freeuk.com> - 2012-03-03 10:30 +0000
        Re: Mechanism to generate annotated "error codes" James Kuyper <jameskuyper@verizon.net> - 2012-03-03 06:19 -0500
        Re: Mechanism to generate annotated "error codes" Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-03-03 15:15 +0200
        Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-03 14:52 +0000
          Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 07:39 -0800
            Re: Mechanism to generate annotated "error codes" Jonathan Leffler <jleffler@earthlink.net> - 2012-03-03 23:56 -0800
              Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 09:20 +1300
                Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-04 13:28 -0800
                Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 10:56 +1300
          Re: Mechanism to generate annotated "error codes" "BartC" <bc@freeuk.com> - 2012-03-03 17:02 +0000
        Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-03 12:30 -0800
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 19:15 -0700
      Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-04 03:20 +0000
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 11:03 -0700
      Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 16:31 -0700
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 23:04 -0700
  Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-02 22:13 -0800
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 00:49 -0700
      Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 03:32 -0800
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 12:04 -0700
          Re: Mechanism to generate annotated "error codes" Lowell Gilbert <lgusenet@be-well.ilk.org> - 2012-03-03 15:06 -0500
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 14:38 -0700
          Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 12:15 -0800
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 16:51 -0700
              Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-04 14:08 -0800
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 15:56 -0700
      Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 03:45 -0800
        Re: Mechanism to generate annotated "error codes" Lowell Gilbert <lgusenet@be-well.ilk.org> - 2012-03-03 14:11 -0500
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 13:03 -0700
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 12:32 -0700
      Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 15:04 -0700
        Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-04 11:09 +1300
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 16:55 -0700
            Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-04 13:04 +1300
              Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 18:24 -0700
        Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 14:30 -0800
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 17:06 -0700
  Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 10:09 +1300
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 16:03 -0700
      Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 13:26 +1300
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 22:21 -0700
          Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 20:46 +1300
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-05 10:54 -0700
              Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-06 10:02 +1300
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-05 16:09 -0700
            Re: Mechanism to generate annotated "error codes" "BartC" <bc@freeuk.com> - 2012-03-06 10:54 +0000
              Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-07 07:22 +1300
  Re: Mechanism to generate annotated "error codes" gordonb.8sa24@burditt.org (Gordon Burditt) - 2012-03-06 08:51 -0600
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-06 11:21 -0700

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