/scala-with-cats

Primary LanguageScala

Scala with Cats

Working through the Scala with Cats book

Chapter 1 - Typeclasses

Used to add extra functions to an existing type

Chapter 2 - Moniods and Semigroups

trait Semigroup[A] {
  def combine(x: A, y: A): A
}

trait Monoid[A] extends Semigroup[A] {
  def empty: A
}

Chapter 3 - Functors

import scala.language.higherKinds

//For appending an operation to a chain

trait Functor[F[_]] {
  def map[A, B](fa: F[A])(f: A => B): F[B]
}

//For prepending an operation to a chain.

trait ContraFunctor[F[_]] {
  def contramap[A, B](fa: F[A])(f: B => A): F[B]
}

//Combination of map and contramap.

trait IFunctor[F[_]] {
  def imap[A, B](fa: F[A])(dec: A => B)(enc: B => A): F[B]
}