Cleaner way to update nested structures

Question

Say I have got following two case classes:

case class Address(street: String, city: String, state: String, zipCode: Int)
case class Person(firstName: String, lastName: String, address: Address)

and the following instance of Person class:

val raj = Person("Raj", "Shekhar", Address("M Gandhi Marg", 
                                           "Mumbai", 
                                           "Maharashtra", 
                                           411342))

Now if I want to update zipCode of raj then I will have to do:

val updatedRaj = raj.copy(address = raj.address.copy(zipCode = raj.address.zipCode + 1))

With more levels of nesting this gets even more uglier. Is there a cleaner way (something like Clojure's update-in) to update such nested structures?

Answer 1

Perhaps QuickLens matches your question better. QuickLens uses macro's to convert an IDE friendly expression into something that is close to the original copy statement.

Given the two example case classes:

case class Address(street: String, city: String, state: String, zipCode: Int)
case class Person(firstName: String, lastName: String, address: Address)

and the instance of Person class:

val raj = Person("Raj", "Shekhar", Address("M Gandhi Marg", 
                                           "Mumbai", 
                                           "Maharashtra", 
                                           411342))

you can update zipCode of raj with:

import com.softwaremill.quicklens._
val updatedRaj = raj.modify(_.address.zipCode).using(_ + 1)