simple (I think) eponymous template question ... what is proper idimatic way ?

[james.p.leblanc]

On Tuesday, 17 August 2021 at 19:44:29 UTC, H. S. Teoh wrote:
>
>
> You could use a helper template and an AliasSeq for this:
>
> 	template isAmong(T, S...) {
> 		static if (S.length == 0)
> 			enum isAmong = false;
> 		else
> 			enum isAmong = is(T == S) ||
> 				isAmong(T, S[1..$]);
> 	}
>
> 	import std.meta : AliasSeq;
> 	alias MyTypes = AliasSeq!(int, float, MySpecialStruct);
>
> 	auto myFunc(T)(T a, T b) if (isAmong!(T, MyTypes)) { ... }
>
>
> T

Dear H.S. Teoh,

Wow!  That is absolutely beautiful ... I had never seen (or even
imagined) a recursive template!  This expands my mind in a good
way ... and is going into my toolbox immediately.

Best Regards,
James