Trying out arrow typeclasses

gistfile1.txt

// in haskell
class Repr a where
  repr :: a -> String

data Sku = Sku { display :: String }

instance Repr Sku where
  repr sku = (display sku)

test =
  let sku = Sku { display = "shoes" }
  in
    repr sku
// test prints "shoes"


// in kotlin
interface Repr<in F> {
    fun F.repr(b: F): String
}

@extension
interface  SkuEntityRepr : Repr<SkuEntity> {
    override fun SkuEntity.repr(b: SkuEntity): String {
        return "{ sku id }"
    }
}

// SkuEntity doesn't need any constructors btw
val test = Repr.repr(SkuEntity()) // unresolved ref repr ?
val test2 = SkuEntity().repr()    // unresolved ref ?