[SOLVED] How to use `asRight` to create Either instance with cats

How to use `asRight` to create Either instance with cats

I am trying to create an instance of Either using asRight in REPL:

import cats._
import cats.data._
import cats.implicits._ 

scala> val x = "xxx".asRight
<console>:20: error: value asRight is not a member of String
       val x = "xxx".asRight
                 ^

scala> import cats.syntax.either._
import cats.syntax.either._

scala> val x = "xxx".asRight
<console>:23: error: value asRight is not a member of String
       val x = "xxx".asRight
                 ^

What's wrong with the code above ? Is it possible to use asRight in REPL ?

Solution

EitherIdOps which includes asRight and asLeft ops was first introduced in cats 0.9.0 (the latest release at the time of writing). You are most likely using an earlier version.

scala> import cats._, implicits._
import cats._
import implicits._

scala> "xxx".asRight
res0: Either[Nothing,String] = Right(xxx)

scala> "xxx".asRight[Int]
res1: Either[Int,String] = Right(xxx)