Set Operations on Set-like Containers

[Andrei Alexandrescu via Digitalmars-d-learn]

On 11/02/2016 11:07 AM, Nordlöw wrote:
> On Wednesday, 2 November 2016 at 13:45:41 UTC, Nordlöw wrote:
>> Typically set- and map-like containers with O(1) key membership checking.
>
> A typical use case is intersection of the two sets `x` and `y`.
>
> When `x` and `y` both support O(1)-`contains(e)` the preferred algorithm
> is to interate over all elements in the shorter (smallest .length) of
> `x` and `y` (called `s`), and return only those elements of type E in
> `s` than can be looked up in `l` via `l.contains(E)`.

Currently we don't have a good framework for associative ranges yet. We 
should define what the associative operations are, and then we can 
proceed to see where they'd make sense. -- Andrei