trace4cats.context.laws.ProvideLaws.scala Maven / Gradle / Ivy

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package trace4cats.context.laws

import cats.laws.{IsEq, IsEqArrow}
import cats.{~>, Monad}
import trace4cats.context.Provide

trait ProvideLaws[Low[_], F[_], R] extends LocalLaws[F, R] with UnliftLaws[Low, F] {
  override implicit def instance: Provide[Low, F, R]

  override implicit def Low: Monad[Low] = instance.Low
  override implicit def F: Monad[F] = instance.F

  // internal laws:
  def askUnliftIsAccessProvideK: IsEq[F[F ~> Low]] =
    instance.access(instance.provideK) <-> instance.askUnlift

  def kleisliftIsLiftAndAccessF[A](f: R => Low[A]): IsEq[F[A]] =
    instance.accessF(r => instance.lift(f(r))) <-> instance.kleislift(f)

  def klesliftAndProvideIsApply[A](f: R => Low[A], r: R): IsEq[Low[A]] =
    instance.provide(instance.kleislift(f))(r) <-> f(r)
}

object ProvideLaws {
  def apply[Low[_], F[_], R](implicit instance0: Provide[Low, F, R]): ProvideLaws[Low, F, R] = {
    new ProvideLaws[Low, F, R] {
      override val instance = instance0
    }
  }
}