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For Cats Effect

Effectie for Cats Effect

All in One Example

import cats._
import cats.syntax.all._
import cats.effect._

import effectie.cats.ConsoleEffectful._
import effectie.cats.Effectful._

import effectie.cats.EitherTSupport._
import effectie.cats.OptionTSupport._
import effectie.cats._

trait Something[F[_]] {
def foo[A: Semigroup](a: A): F[A]
def bar[A: Semigroup](a: Option[A]): F[Option[A]]
def baz[A, B: Semigroup](a: Either[A, B]): F[Either[A, B]]
}

object Something {

def apply[F[_]: Something]: Something[F] =
implicitly[Something[F]]

implicit def something[F[_]: Fx: ConsoleEffect: Monad]: Something[F] =
new SomethingF[F]

final class SomethingF[F[_]: Fx: ConsoleEffect: Monad]
extends Something[F] {

override def foo[A: Semigroup](a: A): F[A] =
for {
n <- effectOf(a)
blah <- pureOf("blah blah")
_ <- effectOf(println(s"n: $n / BLAH: $blah"))
x <- effectOf(n |+| n)
_ <- putStrLn(s"x: $x")
} yield x

override def bar[A: Semigroup](a: Option[A]): F[Option[A]] =
(for {
aa <- a.optionT[F] // OptionT(Applicative[F].pure(a))
blah <- "blah blah".someTF[F] // OptionT(Applicative[F].pure(Some("blah blah")))
_ <- effectOf(
println(s"a: $a / BLAH: $blah")
).someT // OptionT(effectOf(Some(println(s"a: $a / BLAH: $blah"))))
x <- effectOf(a |+| a).optionT // OptionT(effectOf(a |+| a))
_ <- effectOf(putStrLn(s"x: $x")).someT // OptionT(effectOf(Some(putStrLn(s"x: $x"))))
} yield x).value

override def baz[A, B: Semigroup](ab: Either[A, B]): F[Either[A, B]] =
(for {
b <- ab.eitherT[F] // EitherT(Applicative[F].pure(ab))
blah <- "blah blah"
.asRight[A]
.eitherT[F] // EitherT(Applicative[F].pure("blah blah".asRight[A]))
_ <- effectOf(
println(s"b: $b / BLAH: $blah")
).rightT[A] // EitherT(effectOf(Right(println(s"b: $b / BLAH: $blah"))))
x <- effectOf(ab |+| ab).eitherT // EitherT(effectOf(ab |+| ab))
_ <- effectOf(
putStrLn(s"x: $x")
).rightT[A] // EitherT(effectOf(putStrLn(s"x: $x").asRight[A]))
} yield x).value
}
}

println(Something[IO].foo(1).unsafeRunSync())
// n: 1 / BLAH: blah blah
// x: 2
// 2

println(Something[IO].bar(2.some).unsafeRunSync())
// a: Some(2) / BLAH: blah blah
// Some(4)
println(Something[IO].bar(none[String]).unsafeRunSync())
// None

println(Something[IO].baz(2.asRight[String]).unsafeRunSync())
// b: 2 / BLAH: blah blah
// Right(4)
println(Something[IO].baz("ERROR!!!".asLeft[Int]).unsafeRunSync())
// Left(ERROR!!!)