inplace_merge, nWayUnion

[bearophile]

Andrei Alexandrescu:
> My point is you need to understand that you are making contradictory 
> requests.

I understand your point, but I think you are wrong. I think that the usage and semantics of a nWayUnion(r1, r2, ...) are simple to understand and use (regardless the complexity of its signature).

You use it as:
foreach (x; nWayUnion(r1, r2))
Or as:
array(nWayUnion(r1, r2, r3))
etc. This is a natural enough.

Bye,
bearophile