Re: on allowing "int a" definition everywhere

On 22/08/2024 09:40, Blue-Maned_Hawk wrote:

Thiago Adams wrote:
 

On 21/08/2024 01:42, Blue-Maned_Hawk wrote:

Thiago Adams wrote:
>

initializer inside if is already in C++, and it will probably be on
C2Y.

If it's for consistency with how for loops permit declarations, i would
_much_  prefer that they just outlaw that to induce consistency.
>
(Really, i'd ideally want things to just stay as they are, since
declarations in for loops are simply too useful for macros.)

>
I like the ability to declare things inside if.
>
if (FILE* f = fopen("file.txt", "r"))
{
    /*...*/ fclose(f);
}
>
Because it makes the scope of f, associated with the pointed object
lifetime.
>
For instance, if you try to use f
>
if (FILE* f = fopen("file.txt", "r"))
{
    /*...*/ fclose(f);
}
fwrite(f, ..) ;// ERROR

 You can already do that in C23:
 if (…) {
FILE * f = fopen("file.txt", "r");
/* … */
fclose(f);
}
fwrite(f, …);  /* Some kind of error happens. */
 Or, if you need it to exist before the controlling expression:
 for (bool x = true; x; x = false)  for (FILE * f = fopen("file.txt", "r");
x; x = false)  if (…) {
/* … */
fclose(f);
}
fwrite(f, …);
 

I wonder, if I laid it out it properly:
     for (bool x = true; x; x = false)
         for (FILE * f = fopen("file.txt", "r"); x; x = false)
             if (…) {
                 /* … */
                 fclose(f);
             }
     fwrite(f, …);
Nope; I still haven't the faintest idea what this is supposed to do. I suspect that it doesn't actually run or need those two nested loops.
I assume the (...) tests the value of 'f'? If so then perhaps this is a shorter way of expressing the same thing:
     {
         FILE * f = fopen("file.txt", "r");
         if (f) {
             /* … */
             fclose(f);
         }
     }
     fwrite(f, …);