It's a class! It's a struct! It's ... SuperStruct!

[rcorre via Digitalmars-d-announce]

On Thursday, 22 October 2015 at 02:35:34 UTC, rcorre wrote:
>
> Come to think of it, SuperStruct actually sounds pretty similar 
> to std.range.chooseAmong (which I just realized exists).

It seems to work quite nicely as an alternative to choose that 
works with any types as opposed to just ranges:

auto pick(T...)(size_t index, T values) {
   foreach(idx, val ; values)
     if (idx == index)
       return SuperStruct!T(val);

   assert(0, "index not in range of provided values");
}

/// `pick` is useful for something that is a floor wax _and_ a 
dessert topping:
unittest {
   struct FloorWax       { string itIs() { return "a floor wax!";  
      } }
   struct DessertTopping { string itIs() { return "a dessert 
topping!"; } }

   auto shimmer(bool hungry) {
     return pick(hungry, FloorWax(), DessertTopping());
   }

   assert(shimmer(false).itIs == "a floor wax!");
   assert(shimmer(true ).itIs == "a dessert topping!");
}

I can't think of a time I've wanted to do this with something 
_other_ than a range, but hey, its there.