Welcome to Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_79).
Type in expressions to have them evaluated.
Type :help for more information.

scala> import io.circe._
import io.circe._

scala> import io.circe.generic.auto._
import io.circe.generic.auto._

scala> import io.circe.jawn._
import io.circe.jawn._

scala> import io.circe.syntax._
import io.circe.syntax._

scala> case class User(id: Long, name: String, email: String)

defined class User

scala>
scala> :paste
// Entering paste mode (ctrl-D to finish)

val json = """
  {
    "name": "Foo McBar",
    "email": "foo@mcbar.com"
  }
"""


// Exiting paste mode, now interpreting.

json: String =
"
  {
    "name": "Foo McBar",
    "email": "foo@mcbar.com"
  }
"

scala> decode[Long => User](json)
res5: cats.data.Xor[io.circe.Error,Long => User] = Right(<function1>)

scala> res5.map { z => z(100) }
res7: cats.data.Xor[io.circe.Error,User] = Right(User(100,Foo McBar,foo@mcbar.com))

scala> res5.map { z => z(102) }
res8: cats.data.Xor[io.circe.Error,User] = Right(User(102,Foo McBar,foo@mcbar.com))

scala>