One of the thing I like in D

[Dave P.]

On Friday, 11 October 2024 at 23:04:20 UTC, Per Nordlöw wrote:
> On Monday, 7 October 2024 at 20:03:46 UTC, Boaz Ampleman wrote:
>> [...]
>>
>> It's just beautiful
>
> With next dmd you can use use ref variables aswell as
>
> ```d
> void main() {
>     auto a = 0;
>     auto b = 0;
>     const c = 1;
>
>     ref ptr = (c ? a : b);
>     ptr = 8;
>     assert(a == 8);
>     ptr = (c ? b : a);
>     ptr = 2;
>     assert(b == 2); 			// why does this fail??
> }
> ```
>
> But for some reason the last statement doesn't behave as I 
> believe it should. Is this behavior expected?
>
> For reference see 
> https://dlang.org/changelog/pending.html#dmd.reflocal.

`ref` can’t change what it is pointing to. So the second ternary 
is just assigning through the reference, not re-binding the 
reference.

If you re-write the example in terms of pointers, it is 
equivalent to:

```d
void main() {
     auto a = 0;
     auto b = 0;
     const c = 1;

     int* ptr = &(c ? a : b);
     *ptr = 8;
     assert(a == 8);
     *ptr = (c ? b : a);
     *ptr = 2;
}
```