sealed - w3toppers.com

What is a sealed trait?

A sealed trait can be extended only in the same file as its declaration. They are often used to provide an alternative to enums. Since they can be only extended in a single file, the compiler knows every possible subtypes and can reason about it. For instance with the declaration: sealed trait Answer case object … Read more

Iteration over a sealed trait in Scala?

This is actually in my opinion an appropriate use case for 2.10 macros: you want access to information that you know the compiler has, but isn’t exposing, and macros give you a (reasonably) easy way to peek inside. See my answer here for a related (but now slightly out-of-date) example, or just use something like … Read more