Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
import cats.data.Writer
def greetW(name: String, logged: Boolean): Writer[List[String], String] =
Writer(List("Compose a greeting"), {
val userName = if(logged) name else "User"
s"Hello $userName"
})
def isLoggedW(name: String): Writer[List[String], Boolean] =
Writer(List("Checking if user is logged in"), name.length == 3)
import cats.instances.list._
val name = "Joe"
val resultW: Writer[List[String], String] = for {
logged <- isLoggedW(name)
greeting <- greetW(name, logged)
} yield greeting
val (log, result) = resultW.run
val flatMapResult: Writer[List[String], String] = isLoggedW(name).flatMap(logged => greetW(name, logged))
import cats.data.WriterT
import cats.instances.future._
import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global
def greetWFuture(name: String, logged: Boolean): WriterT[Future, List[String], String] =
WriterT(Future(List("Compose a greeting"), {
val userName = if(logged) name else "User"
s"Hello $userName"
}))
def isLoggedWFuture(name: String): WriterT[Future, List[String], Boolean] =
WriterT(Future(List("Checking if user is logged in"), name.length == 3))
val resultWFuture: WriterT[Future, List[String], String] = for {
logged <- isLoggedWFuture(name)
greeting <- greetWFuture(name, logged)
} yield greeting
val futureResult: Future[(List[String], String)] = resultWFuture.run
import scala.concurrent.Await
import scala.concurrent.duration._
val (logAwait, resultAwait) = Await.result(futureResult, 2 second)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment