Characters are quite often compared against zero when doing string handling in C without the binary expression. For this reason I would not want to see this changed.



Now floats on the other hand... there is no clear truthiness value associated with them, unless IEEE-754 defines one (it doesn't appear to for 2008 version).

C23 appears to not define if a floating point type can even convert to bool, although it does mention bool as not being supported in multiple places.

On Tuesday, 30 April 2024 at 18:09:22 UTC, Richard (Rikki) Andrew Cattermole wrote:
> Characters are quite often compared against zero when doing string handling in C without the binary expression. For this reason I would not want to see this changed.
>
>
>
> Now floats on the other hand... there is no clear truthiness value associated with them, unless IEEE-754 defines one (it doesn't appear to for 2008 version).
>
> C23 appears to not define if a floating point type can even convert to bool, although it does mention bool as not being supported in multiple places.

I think the most useful conversion would be.
NaN -> false
because that corresponds to .init

Futhermore you can't simply use == to compare with NaN you need to call isNan(), which complicates writing generic code.

On Tuesday, 30 April 2024 at 18:09:22 UTC, Richard (Rikki) Andrew Cattermole wrote:
> Characters are quite often compared against zero when doing string handling in C without the binary expression. For this reason I would not want to see this changed.


D has the philosophy that valid C code should either behave the same in C as in D, or give an error (c.f. integer promotion rules). It is reasonable to make misleading behaviour like this an error.

On 01/05/2024 3:45 PM, Nicholas Wilson wrote:
> On Tuesday, 30 April 2024 at 18:09:22 UTC, Richard (Rikki) Andrew Cattermole wrote:
>> Characters are quite often compared against zero when doing string handling in C without the binary expression. For this reason I would not want to see this changed.
> 
> 
> D has the philosophy that valid C code should either behave the same in C as in D, or give an error (c.f. integer promotion rules). It is reasonable to make misleading behaviour like this an error.

Both C and D have the same behavior for characters.

```c
#include <stdio.h>

int main()
{
    char c = 0;

    if (c) {
        printf("+\n");
    }

    return 0;
}
```

No output.

```d
import core.stdc.stdio;

void main()
{
    char c = 0;

    if (c) {
        printf("+\n");
    }
}
```

No output.