genkai.monad.MonadError.scala Maven / Gradle / Ivy

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package genkai.monad

// The idea and some implementations ^_^ were found in the sttp project:
// ref. https://github.com/softwaremill/sttp-shared/blob/master/core/src/main/scala/sttp/monad/MonadError.scala
trait MonadError[F[_]] {
  def unit: F[Unit] = pure(())

  def pure[A](value: A): F[A]

  def map[A, B](fa: => F[A])(f: A => B): F[B]

  def flatMap[A, B](fa: => F[A])(f: A => F[B]): F[B]

  def tap[A, B](fa: => F[A])(f: A => F[B]): F[A]

  def raiseError[A](error: Throwable): F[A]

  def adaptError[A](fa: => F[A])(pf: PartialFunction[Throwable, Throwable]): F[A]

  def mapError[A](fa: => F[A])(f: Throwable => Throwable): F[A]

  def handleError[A](fa: => F[A])(pf: PartialFunction[Throwable, A]): F[A]

  def handleErrorWith[A](fa: => F[A])(pf: PartialFunction[Throwable, F[A]]): F[A]

  def ifM[A](fcond: => F[Boolean])(ifTrue: => F[A], ifFalse: => F[A]): F[A]

  def whenA[A](cond: Boolean)(f: => F[A]): F[Unit]

  def void[A](fa: => F[A]): F[Unit]

  def eval[A](f: => A): F[A]

  def suspend[A](fa: => F[A]): F[A] = flatten(eval(fa))

  def flatten[A](fa: => F[F[A]]): F[A] = flatMap(fa)(v => identity(v))

  def guarantee[A](f: => F[A])(g: => F[Unit]): F[A]

  def bracket[A, B](acquire: => F[A])(use: A => F[B])(release: A => F[Unit]): F[B]
}