Scalaz partial modification of immutable objects

lens.scala

scala> import scalaz._
import scalaz._

scala> case class Person(name: String, age: Int)
defined class Person

scala> val nameLens: Lens[Person, String] =
     | Lens((p: Person) => p.name,
     | (p: Person, changed: String) => p.copy(name = changed))
nameLens: scalaz.Lens[Person,String] = Lens(<function1>,<function2>)

scala> val ageLens: Lens[Person, Int] =
     | Lens((p: Person) => p.age,
     | (p: Person, changed: Int) => p.copy(age = changed)) 
ageLens: scalaz.Lens[Person,Int] = Lens(<function1>,<function2>)

scala> val p = Person("George", 24)
p: Person = Person(George,24)

scala> val p2 = ageLens.set(p, 25)
p2: Person = Person(George,25)

scala> nameLens.set(p2, "OtherName")
res2: Person = Person(OtherName,25)

zipper.scala

scala> import Scalaz._
import Scalaz._

scala> val z = zipper(Stream(9, 11), 7, Stream(23, 9))
z: scalaz.Zipper[Int] = <zipper>

scala> z.shows
res3: String = [11,9] 7 [23,9]

scala> val znext = z.tryNext
znext: scalaz.Zipper[Int] = <zipper>

scala> znext.shows
res4: String = [11,9,7] 23 [9]

scala> val zinsertl = znext.insertLeft(11)
zinsertl: scalaz.Zipper[Int] = <zipper>

scala> zinsertl.shows
res6: String = [11,9,7] 11 [23,9]

scala> val zinsertr = znext.insertRight(89)
zinsertr: scalaz.Zipper[Int] = <zipper>

scala> zinsertr.shows
res7: String = [11,9,7,23] 89 [9]