Compare Two UUID Using Scalaz ===

Question

What do I need to do to compare two Java UUIDs? Do I need to create an instance of the Equal typeclass for java.util.UUID?

Answer 1

I assume you want to compare whether two UUIDs have the same value rather than the object references, in which case, the following suffices:

import scalaz._
import Scalaz._
import java.util.UUID

object UUIDEqualExample extends App {

  val a = new UUID(12345678, 87654321)
  val b = new UUID(12345678, 87654321)
  val c = new UUID(11111111, 22222222)

  implicit val eq: Equal[UUID] = Equal.equalA[UUID]

  println(a === b) // true
  println(a === c) // false

}