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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Do you insist on const-correctness?
Date: Sat, 23 Sep 2023 11:57:14 -0700
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Anton Shepelev <anton.txt@g{oogle}mail.com> writes:

> Tim Rentsch to Anton Shepelev:
>
> [an unused variable removed from quoted code:]
>
>>> void* a_setlen( void * a, unsigned len )
>>> {  struct meta_t *m    ;
>>>
>>>    m = META  ( a      );
>>>    m = setlen( m, len );
>>>    if( m != NULL ) a = DATA( m );
>>>    else            a = NULL     ;
>>>    return a;
>>> }
>>
>> Is there some reason not to write a shorter and simpler
>> function, such as the function below (please ignore
>> differences in layout style)
>>
>>     void*
>>     a_setlen( void *a, unsigned n ){
>>         struct meta_t *const m = setlen( META( a ), n );
>>
>>         return  m ? DATA( m ) : NULL;
>>     }
>
> My personal reasons are the following:
>
>   1.  I prefer not to mix variable declaration and
>       initialisation, but first to declare my data and then
>       to work with it.
>
>   2.  I consider nested calls a bit less readable than
>       sequential, alghough I do not alwasy avoid them.
>
>   3.  Sequential calls let me insert ad-hoc debugging code
>       at the right points, e.g. between the invocations of
>       META() and setlen() above.
>
>   4.  I consider the ternary operator a redundant special
>       case of the `if' statement that increases expression
>       nesting to the (granted, often but slight) detriment
>       of readability.
>
> I have snipped your comments about `const', but not without
> having perused them.

I have reflected on these comments and also some of the responses
you have given to other posters.  Here are some high-level
reactions (without specifics).

One:  all of your preferences basically boil down to "this is
what I'm used to".

Two:  you really need to learn new ways of thinking.  You won't
see (I predict) the advantages of alternative approaches until
after you have assimilated them.  If you don't make an effort to
try and embrace other approaches you'll be caught in a vicious
cycle.

Three:  Why should you give any weight to my suggestions?  Think
about this: I have been where you are.  All of the things you're
saying are things I might have said earlier in my programming
experience.  Fortunately I got some guidance from some very smart
people and was able to learn new ways of thinking about programs.

As an exercise try writing a_setlen() like this (and I mean
really try it, put the code in and get it to compile).  Don't
complain about how awful it looks, I know it's different from
what you're used to.

    void *
    ATEM( struct meta_t *m ){
        return  m ? DATA( m ) : NULL;
    }

    void*
    a_setlen( void *a, unsigned n ){
        return  ATEM( setlen( META( a ), n ) );
    }

Needless to say 'ATEM' is 'META' spelled backwards.  If you
think of a more suitable name feel free to use it, otherwise
exactly like this (with my usual caveat to ignore differences
in layout style).