Re: [PC] Simple AST

From	David Brown <david.brown@hesbynett.no>
Newsgroups	comp.lang.c
Subject	Re: [PC] Simple AST
Date	2019-03-06 23:29 +0100
Organization	A noiseless patient Spider
Message-ID	<q5phk8$ej9$1@dont-email.me> (permalink)
References	(5 earlier) <86ef7kufly.fsf@mailhub.linuxsc.com> <m27edb52f3.fsf@despina.home> <ln36nznb3r.fsf@kst-u.example.com> <m2wolb3kj4.fsf@despina.home> <C6VfE.143510$Xct1.59455@fx12.am4>

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On 06/03/2019 20:23, Bart wrote:
> On 06/03/2019 18:49, Pascal J. Bourguignon wrote:
>> Keith Thompson <kst-u@mib.org> writes:
>>
>>> "Pascal J. Bourguignon" <pjb@informatimago.com> writes:
>>> [...]
>>>> 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.
>>>
>>> So don't do that.  How often do you actually see code like that?
>>>
>>>      a = b + c*d;
>>>
>>> It would be nice if compilers warned about misleading spaces in
>>> expressions (perhaps some do).

I don't know of any.  Recent gcc can warn about misleading indentation, 
which is nice, but not about spacing in expressions.

>>
>> Often enough.  But the worst part, is that I never encoutered any C
>> programmer able to recite from memory the list of all C opertors sorted
>> by their exact priority level.  Therefore not using systematically
>> parentheses in any C expressions is a sure way to introduce slimy bugs.
> 
> One or two here claim to know the precedences by heart, notably Tim 
> Rentsch.
> 
> It gets dangerous when they expect everyone else to know them, so their 
> own code is largely devoid of parentheses.
> 
>> (I'm not able to do it for C either, when I programmed in pascal, I
>> could do it for pascal operators).
> 
> 
> C is a basket-case because there are so many precedences (10 just for 
> binary operators, which is a little crazy (have == and <= different, and 
> which one is higher and which lower?), and many are unintuitive.
> 

Many of the C operator precedences are quite obvious and sensible.  The 
others are reasonable enough if you think about hard enough - but 
personally I find they can be difficult to grasp immediately.  I'll 
write "(a < 1) && (b > 1)", even though the parentheses are not needed 
here.  But I write "a = b + c * d" without parentheses (and with that 
spacing).

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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