Type all the things

jto.github.io

9 pointslmm4 comments

Haskell has newtype for this purpose, with the benefit that the compiler removes the added overhead of the additional data type.

Value classes serve this purpose in Scala: `case class Id(id: Long) extends AnyVal` will have long-typed values at runtime (*mostly).

Is *mostly even true?

It seems to me that you'd have to be fairly careful to have any confidence your not instantiating classes for them.

Do you know if there are any compiler flags or other way to know if your value classes are working as expected?

> [Re: Type Safety] It may not feel like much, but it is huge. Here I can only ask you to believe me.

That was the part I agreed with you the most.