Inferring static array size

[NotYouAgain]

On Friday, 3 May 2024 at 07:48:01 UTC, rkompass wrote:
>
> I actually find this counterintuitive. Because [..] in my 
> intuition looks like a dynamic array. But it's about creating a 
> static array.
> ...

[..] is a slice thing - it's not related to how the array came 
into existence.

i.e it can work on a static array, and a dynamic array (see code 
example below).

Perhaps for that reason, [..] might not be suitable after all.

perhaps [$] is still the best, since $ *always* simply refers to 
the length of the array.

so:

int[4] // 4 is the length
int[$] // $ is still the length, you just don't know what it is 
yet.

module m;
@safe:
private:
import std;

void main()
{
     auto a = [1, 2, 3, 4, 5].staticArray;
     //auto a[$] = [1, 2, 3, 4, 5]; // the compiler can infer the 
'length'

     writeln(fold!((a, b) => a + b)(a[0..2])); // 3  (see: [..] 
used on a static array.
}