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@Moverr
Created December 15, 2023 22:20
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Json writer emulating type classes
sealed trait json
final case class jsString(get: String) extends json
final case class jsObject(get: Map[String, json]) extends json
final case class jsNumber(get: Double) extends json
case object jsNull extends json
trait JsonWriter[A] {
def write(value: A): json
}
// the instances
final case class Person(name: String, email: String)
object jsonWriterInstances {
implicit val stringWriter: JsonWriter[String] = new JsonWriter[String] {
def write(value: String): json = {
jsString(value)
}
}
implicit val personWriter: JsonWriter[Person] =
new JsonWriter[Person] {
def write(value: Person): json = {
jsObject(
Map(
"name" -> jsString(value.name),
"email" -> jsString(value.email)
)
)
}
}
}
object json {
def toJson[A](value: A)(implicit w: JsonWriter[A]): json =
w.write(value)
}
json.toJson("Rogers")(jsonWriterInstances.stringWriter)
val pp = Person("movers name", "moverr@gmail.com")
json.toJson(pp)(jsonWriterInstances.personWriter)
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