alt Hacker NewsLike a lot of other languages, Java has gotten a big dose of
https://en.wikipedia.org/wiki/Hindley%E2%80%93Milner_type_sy...
To defy it's reputation for verbosity, Java's lambda syntax is both terse and highly flexible. Sum and product types are possible with records and sealed classes. Pattern matching.
I even found a way to make ad-hoc union types of element types from other packages that does exhaustive switch/case checking. I quickly wrote down a PoC so I wouldn't forget[0]. It needs wrapper types and sealed interfaces in the consuming app/package but is manageable and turned out better than other attempts I'd made.
[0] https://github.com/karmakaze/AdHocUnion