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Version: v1

Log - Scalaz

Log - Scalaz (WIP)

Log is a typeclass to log F[A], F[Option[A]], F[A \/ B], OptionT[F, A] and EitherT[F, A, B].

It requires Fx from Effectie and Monad from Scalaz.

Log F[A]

Log[F].log(F[A])(A => String)


trait Named[A] {
def name(a: A): String

object Named {
def apply[A: Named]: Named[A] = implicitly[Named[A]]

final case class GivenName(givenName: String) extends AnyVal
final case class Surname(surname: String) extends AnyVal

final case class Person(givenName: GivenName, surname: Surname)
object Person {
implicit val namedPerson: Named[Person] =
person => s"${person.givenName.givenName} ${person.surname.surname}"

import scalaz._
import Scalaz._
import scalaz.effect._

import effectie.scalaz.Fx
import effectie.scalaz.ConsoleEffect
import effectie.scalaz.Effectful._

import loggerf.logger._
import loggerf.scalaz._
import loggerf.syntax._

trait Greeting[F[_]] {
def greet[A: Named](a: A): F[String]

object Greeting {
def apply[F[_] : Greeting]: Greeting[F] = implicitly[Greeting[F]]

implicit def hello[F[_]: Fx: Monad: Log]: Greeting[F] =
new Greeting[F] {
def greet[A: Named](a: A): F[String] = for {
name <- log(effectOf(Named[A].name(a)))(x => info(s"The name is $x"))
greeting <- pureOf(s"Hello $name")
} yield greeting


object MyApp {

implicit val canLog: CanLog = Slf4JLogger.slf4JCanLog("MyApp")

def run(args: List[String]): IO[Unit] = for {
greetingMessage <- Greeting[IO].greet(Person(GivenName("Kevin"), Surname("Lee")))
_ <- ConsoleEffect[IO].putStrLn(greetingMessage)
} yield ()

def main(args: Array[String]): Unit =
21:02:15.323 [ioapp-compute-0] INFO MyApp - The name is Kevin Lee
Hello Kevin Lee

Log F[Option[A]]

Log OptionT[F, A]

Log F[A \/ B]

Log EitherT[F, A, B]