monocle automatically generated lenses example

lenses.scala

package monocle

import monocle.macros.{GenLens, Lenses}
import shapeless.test.illTyped

class LensMonoExample extends MonocleSuite {
  // @Lenses generate Lens automatically in the companion object
  @Lenses case class Address(streetNumber: Int, streetName: String)
  @Lenses case class Person(name: String, age: Int, address: Address)

  val john = Person("John", 30, Address(126, "High Street"))
  
  test("get") {
    Person.name.get(john)  shouldEqual "John"
  }
  
  test("set") {
    val changedJohn = john.copy(age = 45)
    
    Person.age.set(45)(john)  shouldEqual changedJohn
  }
  
  test("compose") {
    (Person.address composeLens Address.streetNumber).get(john)  shouldEqual 126
  }
  
  test("Modifications through lenses are chainable") {
    @Lenses case class Point(x: Int, y: Int)
    import Point._

    val update = x.modify(_ + 100) compose y.set(7)
    update(Point(1,2)) shouldEqual Point(101,7)
  }
}