Re: Which code style do you prefer the most?

On 02/03/2025 09:21, Tim Rentsch wrote:

scott@slp53.sl.home (Scott Lurndal) writes:
 

Kaz Kylheku <643-408-1753@kylheku.com> writes:
>

On 2025-02-26, Ar Rakin <rakinar2@onesoftnet.eu.org> wrote:
>

Sorry, I should have showed this difference in my original post.
I like the GNU style except the weird indentation before the
braces of control statements.  Not sure why they choose to indent
that way.
>
The GNU style without indent before braces looks nice to me.

>
Without the weird brace indent, it has nothing to do with GNU any
more;  it's just two-space indentation, where opening braces are on
their own line instead of being "cuddled" into the previous line,
which is very common:
>
  if (flag)
  {
    switch (state)
    {
      case 42:
      {
        state = 73;
        break;
      }
    }
  }
  else
  {
    statement;
  }

>
There's so much vertical space wasted in that, however.
>
   if (flag && (state == 42)) state = 73;
   else                       statement;

The semantics here are different, yes - if "flag" is true and "state" is not 42, the original version does not run "statement;" while the re-write does run it.

 The suggested rewrite has different semantics.  Instead
      if(flag)  state = state == 42 ? 73 : state;
     else      statement;
 

The semantics here are different from the original - introducing a spurious write to "state" could be observable behaviour or subject to an additional data race if "state" is "volatile", atomic, or interacts with other threads.

or
      if(flag)  state != 42 || (state = 73);
     else      statement;
 has the same behavior as the original.  (Disclaimer: not
compiled.)

The semantics here are also possibly different from the original if "state" is volatile or atomic.  The details of volatile accesses are implementation-defined - the evaluation "(state = 73)" with a volatile "state" may re-read "state" after the assignment, or may not.
Re-writes of code can have subtle complications when you don't know the full context.  This is one reason people working on serious and safety-critical software don't faff around with expressions like those ones, and prefer clear and unambiguous code that can't be misinterpreted by other programmers, or compilers, regardless of the circumstances.  If you want to eliminate the switch, consider this :
     if (flag) {
         if (state == 42) {
             state = 73;
         }
     } else {
         statement;
     }
Yes, it is more verbose - but it is absolutely clear, and there is no doubt what is going on even if there are volatiles, atomics, or threads involved.