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Groups > comp.lang.c > #141740

Re: [PC] Simple AST

From "Pascal J. Bourguignon" <pjb@informatimago.com>
Newsgroups comp.lang.c
Subject Re: [PC] Simple AST
Date 2019-03-06 18:38 +0100
Organization Informatimago
Message-ID <m27edb52f3.fsf@despina.home> (permalink)
References (1 earlier) <q4hrja$iv0$1@news.albasani.net> <e94db73c-151b-472f-83dc-2f6f4b96dfa6@googlegroups.com> <ui3q6e95k7lls5428eum681c7jd3f517mi@4ax.com> <m2pnrm97mc.fsf@despina.home> <86ef7kufly.fsf@mailhub.linuxsc.com>

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Tim Rentsch <tr.17687@z991.linuxsc.com> writes:

> "Pascal J. Bourguignon" <pjb@informatimago.com> writes:
>
>> Rosario19 <Ros@invalid.invalid> writes:
>>
>>> [..concerning whitespace in program source..]
>>>
>>> one program language without white spaces has readability == 0
>>
>> Not really.  If you can still use tab for indents, you're ok.
>>
>> int main(){
>>    int a=42;
>>    int b=33;
>>    if((a<b)||(33==b)){
>>       printf("less\n");}
>>    else{
>>       printf("more\n");}
>>    return(0);}
>>
>>> the true because program now are more readable it is not because
>>> they invent loop instructions (for break ecc) and structural
>>> instructions but main, because **indentation** and visual
>>> rememeber of loop and using indentation and spaces for show
>>> rendundance in the code...
>>
>> Don't use spaces other than where required to separate tokens, and
>> for indentation (spaces pay more than tabs).  But don't use them
>> in expression:  they're misleading!
>>
>>     a = b+c * d; // spaces fail all the time.
>>
>> Instead, use parentheses:
>>
>>     a=(b+(c*d));
>
> This advice has it exactly backwards.  For visual separation,
> spaces are better than parentheses because they are a better
> match to human perceptual hardware.  For semantic grouping,
> variable spacing is better than parentheses, both because it is
> more readily perceived, and because it offers a redundancy that
> can be used as a check on what the author intended.  The
> "misleadingness" in the example (and other similar examples) can
> be programmatically detected, and provides a tipoff that there is
> something wrong - either a misunderstanding on the part of the
> author, or a mistake in the algorithm, or perhaps both.  Using
> spacing to (redundantly) show grouping adds useful information.
> Taking out all spaces and putting in redundant parentheses takes
> away information that is often useful - a losing proposition all
> the way around.

We are not looking at landscape and scanning for predators here.

We're looking at code that needs to give the human reader a conceptual
structure isomorphe to what the "semantics" implemented by the language
implementation produces.

     a = b+c * d; // spaces fail all the time.

-- 
__Pascal J. Bourguignon__
http://www.informatimago.com

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Thread

[PC] Simple AST luser droog <luser.droog@gmail.com> - 2019-02-16 14:23 -0800
  Re: [PC] Simple AST BGB <cr88192@hotmail.com> - 2019-02-19 15:14 -0600
    Re: [PC] Simple AST luser droog <luser.droog@gmail.com> - 2019-02-19 19:51 -0800
      Re: [PC] Simple AST Rosario19 <Ros@invalid.invalid> - 2019-02-20 09:28 +0100
        Re: [PC] Simple AST "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-02-20 09:39 +0100
          Re: [PC] Simple AST Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-06 08:34 -0800
            Re: [PC] Simple AST "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-06 09:02 -0800
              Re: [PC] Simple AST "I Set My Girlfriend's Pantyhose on Fire" <cdalten@gmail.com> - 2019-03-06 11:14 -0800
              Re: [PC] Simple AST Ian Collins <ian-news@hotmail.com> - 2019-03-07 14:11 +1300
                Re: [PC] Simple AST "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-06 17:48 -0800
                Re: [PC] Simple AST Ian Collins <ian-news@hotmail.com> - 2019-03-07 15:21 +1300
                Re: [PC] Simple AST luser droog <luser.droog@gmail.com> - 2019-03-06 18:28 -0800
                Re: [PC] Simple AST luser droog <luser.droog@gmail.com> - 2019-03-06 18:37 -0800
                Re: [PC] Simple AST "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-06 18:47 -0800
                Re: [PC] Simple AST luser droog <luser.droog@gmail.com> - 2019-03-06 18:53 -0800
            Re: [PC] Simple AST "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-03-06 18:38 +0100
              Re: [PC] Simple AST Keith Thompson <kst-u@mib.org> - 2019-03-06 09:53 -0800
                Re: [PC] Simple AST "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-06 09:59 -0800
                Re: [PC] Simple AST "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-03-06 19:49 +0100
                Re: [PC] Simple AST Bart <bc@freeuk.com> - 2019-03-06 19:23 +0000
                Re: [PC] Simple AST David Brown <david.brown@hesbynett.no> - 2019-03-06 23:29 +0100
                Re: [PC] Simple AST BGB <cr88192@hotmail.com> - 2019-03-06 21:54 -0600
                Re: [PC] Simple AST James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-08 18:52 -0500
                Re: [PC] Simple AST "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-03-09 01:56 +0100
                Re: [PC] Simple AST Keith Thompson <kst-u@mib.org> - 2019-03-08 18:22 -0800
                Re: [PC] Simple AST David Brown <david.brown@hesbynett.no> - 2019-03-09 14:02 +0100
                Re: [PC] Simple AST Keith Thompson <kst-u@mib.org> - 2019-03-09 12:20 -0800
                Re: [PC] Simple AST David Brown <david.brown@hesbynett.no> - 2019-03-10 00:04 +0100
                Re: [PC] Simple AST Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-09 02:28 +0000
                Re: [PC] Simple AST BGB <cr88192@gmail.com> - 2019-03-08 23:06 -0600
                Re: [PC] Simple AST Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-12 23:06 -0700
                Re: [PC] Simple AST Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-03-14 06:48 +0000
                Re: [PC] Simple AST James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-14 07:14 -0400
                Re: [PC] Simple AST Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-03-14 14:58 +0000
                Re: [PC] Simple AST James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-14 10:13 -0700
                Re: [PC] Simple AST Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-18 08:34 -0700
                Re: [PC] Simple AST Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-23 10:57 -0700
                Re: [PC] Simple AST James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-25 11:42 -0700
                Re: [PC] Simple AST Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-18 07:18 -0700
                Re: [PC] Simple AST Bart <bc@freeuk.com> - 2019-03-14 15:34 +0000
                Divorcing rabbits with Tim R (Was: [PC] Simple AST) gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-14 16:52 +0000
                Re: [PC] Simple AST Keith Thompson <kst-u@mib.org> - 2019-03-06 22:12 -0800
                Re: [PC] Simple AST David Brown <david.brown@hesbynett.no> - 2019-03-07 08:54 +0100
                Re: [PC] Simple AST "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-07 03:20 -0800
                Re: [PC] Simple AST Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-12 23:08 -0700
                Re: [PC] Simple AST luser droog <luser.droog@gmail.com> - 2019-03-06 14:08 -0800
                Re: [PC] Simple AST Keith Thompson <kst-u@mib.org> - 2019-03-06 22:13 -0800
              Re: [PC] Simple AST Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-06 19:38 +0000
                Re: [PC] Simple AST "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-06 11:54 -0800
                Re: [PC] Simple AST Anton Shepelev <anton.txt@g{oogle}mail.com> - 2019-03-07 14:43 +0300
                Re: [PC] Simple AST "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-07 03:58 -0800
                Re: [PC] Simple AST David Brown <david.brown@hesbynett.no> - 2019-03-07 13:07 +0100
        Re: [PC] Simple AST Rosario19 <Ros@invalid.invalid> - 2019-02-20 10:35 +0100
    Re: [PC] Simple AST Bart <bc@freeuk.com> - 2019-02-20 14:26 +0000
      Re: [PC] Simple AST BGB <cr88192@hotmail.com> - 2019-02-20 14:32 -0600
        Re: [PC] Simple AST "I Set My Girlfriend's Pantyhose on Fire" <cdalten@gmail.com> - 2019-02-21 13:38 -0800
        Re: [PC] Simple AST Thiago Adams <thiago.adams@gmail.com> - 2019-02-22 04:03 -0800

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