inferred size for static array initialization

[Basile B via Digitalmars-d-learn]

On Monday, 2 May 2016 at 13:22:01 UTC, Basile B 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
>
> Help yourself with a template:
>
> ----
> import std.traits;
>
> auto toStaticArray(alias array)()
> if (isArray!(typeof(array)))
> {
>     enum size = array.length;
>     alias T = typeof(array.init[0])[size];
>     T result = array[0..size];
>     return result;
> }
>
> enum a = toStaticArray!([1,2,3]);
> static assert(isStaticArray!(typeof(a)));  // success
> ----
>
> Does it fit ?

Using an enum is probably a bit better

----
auto toStaticArray(alias array)()
if (isDynamicArray!(typeof(array)) && array.length)
{
     alias T = typeof(array[0])[array.length];
     enum T result = array[0..array.length];
     return result;
}