PEFP2.scala

import cats.Semigroup
import cats.implicits._

// Combining strings

"Semigroups".combine(" ".combine("combine".combine(" ".combine("things")))) 
// res1: String = "Semigroups combine things

// Which is hard to read so Cats provides convenient infix syntax

"Semigroups" |+| " " |+| "combine" |+| " " |+| "things" 
// res2: String = "Semigroups combine things"

// Combining Integers

10 |+| 20  
// res3: Int = 30

// Combining Tuples of Semigroups

(1, "two") |+| (3, "four") 
// res4: (Int, String) = (4, "twofour")

// Combining Futures of Either[String,Int]

import scala.concurrent.ExecutionContext.Implicits.global 
import scala.concurrent.Future

Future(10.asRight[String]) |+| Future(20.asRight[String]) 
// res5: Future[Either[String, Int]] = Future(Success(Right(30)))