Isn't the whole article a discussion of the kind of guarantees such an approach (which can also be done in Haskell) cannot provide?
Isn't the whole article a discussion of the kind of guarantees such an approach (which can also be done in Haskell) cannot provide?
Right, I'm just unsure how valuable those guarantees really are. Especially if I'm extracting an Int out of the type to interface with other code.
> Especially if I'm extracting an Int out of the type to interface with other code.
Why would you do this? As soon as you go "outside" the type you lose typechecker guarantees.
The whole point of the article is showing where the compiler can tell you when you're writing code that fails to consider some cases, and how use of `newtype` loses some of these guarantees.
I don't think I'm gonna find a library that supports my OneToFive type.
Your type comes with its own library, and the compiler makes sure you're not misusing it by failing to consider a possible case.
If you need to use your OneToFive someplace that actually wants an integer, that happens at the boundary. Everything else is safer.