SemigroupK

SemigroupK is a universal semigroup which operates on kinds.

This type class is useful when its type parameter F[_] has a structure that can be combined for any particular type. Thus, SemigroupK is like a Semigroup for kinds (i.e. parametrized types).

A SemigroupK[F] can produce a Semigroup[F[A]] for any type A.

Here's how to distinguish Semigroup and SemigroupK:

Semigroup[A] allows two A values to be combined.
SemigroupK[F] allows two F[A] values to be combined, for any A. The combination operation just depends on the structure of F, but not the structure of A.

Self Type: SemigroupK[F]

Linear Supertypes

Serializable, Serializable, Any

Known Subclasses

Alternative, MonoidK

Abstract Value Members

abstract def combineK[A](x: F[A], y: F[A]): F[A]

Combine two F[A] values.

Example:

scala> import cats.implicits._
scala> SemigroupK[List].combineK(List(1, 2), List(3, 4))
res0: List[Int] = List(1, 2, 3, 4)

Annotations: @op( "<+>" , true )

abstract def getClass(): Class[_]

Definition Classes
Any

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
Any
final def ##(): Int

Definition Classes
Any
final def ==(arg0: Any): Boolean

Definition Classes
Any
def algebra[A]: Semigroup[F[A]]

Given a type A, create a concrete Semigroup[F[A]].
Given a type A, create a concrete Semigroup[F[A]].
Example:
```
scala> import cats.implicits._
scala> val s: Semigroup[List[Int]] = SemigroupK[List].algebra[Int]
```
final def asInstanceOf[T0]: T0

Definition Classes
Any

def compose[G[_]]: SemigroupK[[α]F[G[α]]]

"Compose" with a G[_] type to form a SemigroupK for λ[α => F[G[α]]].

"Compose" with a G[_] type to form a SemigroupK for λ[α => F[G[α]]]. Note that this universally works for any G, because the "inner" structure isn't considered when combining two instances.

Example:

scala> import cats.implicits._
scala> type ListOption[A] = List[Option[A]]
scala> val s: SemigroupK[ListOption] = SemigroupK[List].compose[Option]
scala> s.combineK(List(Some(1), None, Some(2)), List(Some(3), None))
res0: List[Option[Int]] = List(Some(1), None, Some(2), Some(3), None)

def equals(arg0: Any): Boolean

Definition Classes
Any
def hashCode(): Int

Definition Classes
Any
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
def toString(): String

Definition Classes
Any

Related Docs: object SemigroupK | package cats

trait SemigroupK[F[_]] extends Serializable

Abstract Value Members

abstract def combineK[A](x: F[A], y: F[A]): F[A]

abstract def getClass(): Class[_]

Concrete Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

def algebra[A]: Semigroup[F[A]]

final def asInstanceOf[T0]: T0

def compose[G[_]]: SemigroupK[[α]F[G[α]]]

def equals(arg0: Any): Boolean

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

def toString(): String

Inherited from Serializable

Inherited from Serializable

Inherited from Any

Ungrouped