Re: 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;
}