Re: [PC] Simple AST

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: [PC] Simple AST
Date	2019-03-06 19:38 +0000
Organization	A noiseless patient Spider
Message-ID	<87h8cfbxo9.fsf@bsb.me.uk> (permalink)
References	(2 earlier) <e94db73c-151b-472f-83dc-2f6f4b96dfa6@googlegroups.com> <ui3q6e95k7lls5428eum681c7jd3f517mi@4ax.com> <m2pnrm97mc.fsf@despina.home> <86ef7kufly.fsf@mailhub.linuxsc.com> <m27edb52f3.fsf@despina.home>

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"Pascal J. Bourguignon" <pjb@informatimago.com> writes:

> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>
>> "Pascal J. Bourguignon" <pjb@informatimago.com> writes:
<cut>
>>> 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.

Surely that's a win?  If the code is using spaces as Tim suggests it
flags up a bug, at least it leaps out at me: "programmer is either
confused about layout or confused about operators -- double check the
intent and correct one or the other".

-- 
Ben.

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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