inferred size for static array initialization

[Steven Schveighoffer via Digitalmars-d-learn]

On 5/2/16 1:43 PM, Namespace wrote:
> On Monday, 2 May 2016 at 13:00:27 UTC, Erik Smith wrote:
>> Is there a way to initialize a static array and have it's size
>> inferred (and that works for arrays of structs using braced
>> literals)?  This would make it easier to maintain longer static array
>> definitions.  The code below doesn't work when removing the array size
>> even though the array is declared as static immutable.
>>
>>     import std.traits;
>>     static immutable int[] a  = [1,2,3];
>>     static assert(isStaticArray!(typeof(a)));  // fails
>
> I still like
> ----
> auto s(T, size_t n)(T[n] arr) {
>      return arr;
> }

Interesting. But there is a major problem here...

>
> auto arr = [1, 2, 3].s;
> ----
>
> But of course this won't work:
> ----
> int[] a  = [1,2,3].s;
> static assert(isStaticArray!(typeof(a)));  // fails
> ----

And this is the problem.

> Since 'a' is just a slice.

A slice of a no-longer-existing temporary! Admittedly, this is not an 
issue with your code, but a deeper issue of allowing slicing of rvalues.

>
> But this will work:
> ----
> immutable auto a  = [1,2,3].s;
> ----

You can drop auto. It's just a placeholder for the storage class in the 
case where a storage class isn't specified.

-Steve