Remix clone Hacker News

I'm not completely sure what this example is trying to illustrate. Most languages with proper sum types would have `Map<K, V>.get` return an `Optional<V>`. If V happens to be `Optional<Integer>`, then the result will be an `Optional<Optional<Integer>>`, which is a perfectly good type that represents the two ways a value may be missing from the map.

Am I missing something?

▲ pbh101 5 hours ago | parent [-]

The Map interface pre-dates Optional and does not return Optional, so it won't return an empty Optional but rather null.

To be more clear:

    Map<K, V>.get(foo)

returns a `V`, not an `Optional<V>`. If your `V` is `Optional<WrappedV>`, cool, but that doesn't change that `Map` either finds or doesn't find a V.

	▲	stickfigure 4 hours ago \| parent [-]
		The parent certainly knows this. Additional methods could be added to `Map` which return `Optional`. I am annoyed by their absence every day.