tagging

Tag instances with arbitrary types. The tags are usually empty traits. Tags have no runtime overhead and are only used at compile-time for additional type safety.

For example:

class Berry()

trait Black
trait Blue

val berry = new Berry()
val blackBerry: Berry @@ Black = berry.taggedWith[Black]
val blueBerry: Berry @@ Blue = berry.taggedWith[Blue]

// compile error: val anotherBlackBerry: Berry @@ Black = blueBerry

Original idea by Miles Sabin, see: https://gist.github.com/milessabin/89c9b47a91017973a35f

Linear Supertypes

AnyRef, Any

Type Members

type @@[+T, +U] = T with Tag[U]
implicit final class AndTagger[T, U] extends AnyVal
implicit final class AndTaggingF[F[_], T, U] extends AnyVal
implicit final class AndTaggingF2[F1[_], F2[_], T, U] extends AnyVal
implicit final class AndTaggingMapKey[M[_, _], K, A, V] extends AnyVal
trait AnyTypeclassTaggingCompat extends AnyRef
implicit final class Function2Tagger[A, B, C] extends AnyVal
implicit final class Function3Tagger[A, B, C, D] extends AnyVal
implicit final class Function4Tagger[A, B, C, D, E] extends AnyVal
implicit final class FunctionTagger[A, B] extends AnyVal
trait Tag[+U] extends Any
type Tagged[+T, +U] = T with Tag[U]
implicit final class Tagger[T] extends AnyVal
implicit final class TaggingF[F[_], T] extends AnyVal
implicit final class TaggingF2[F1[_], F2[_], T] extends AnyVal
implicit final class TaggingMapKey[M[_, _], K, V] extends AnyVal
trait TypeclassTaggingCompat[Typeclass[_]] extends AnyRef

package tagging

Type Members

type @@[+T, +U] = T with Tag[U]

implicit final class AndTagger[T, U] extends AnyVal

implicit final class AndTaggingF[F[_], T, U] extends AnyVal

implicit final class AndTaggingF2[F1[_], F2[_], T, U] extends AnyVal

implicit final class AndTaggingMapKey[M[_, _], K, A, V] extends AnyVal

trait AnyTypeclassTaggingCompat extends AnyRef

implicit final class Function2Tagger[A, B, C] extends AnyVal

implicit final class Function3Tagger[A, B, C, D] extends AnyVal

implicit final class Function4Tagger[A, B, C, D, E] extends AnyVal

implicit final class FunctionTagger[A, B] extends AnyVal

trait Tag[+U] extends Any

type Tagged[+T, +U] = T with Tag[U]

implicit final class Tagger[T] extends AnyVal

implicit final class TaggingF[F[_], T] extends AnyVal

implicit final class TaggingF2[F1[_], F2[_], T] extends AnyVal

implicit final class TaggingMapKey[M[_, _], K, V] extends AnyVal

trait TypeclassTaggingCompat[Typeclass[_]] extends AnyRef

Value Members

object AnyTypeclassTaggingCompat extends AnyTypeclassTaggingCompat

Inherited from AnyRef

Inherited from Any

Ungrouped