super simple memo on typeclasses with generics

typeclassesABC.scala

trait Json[T] {
 def toJson(t:T):String
}

implicit object jsonStr extends Json[String] {
 def toJson(s:String) = s""""$s""""
}

implicit object jsonInt extends Json[Int] {
 def toJson(s:Int) = s"$s"
}

implicit def jsonSet[T:Json] = new Json[Set[T]] {
  def toJson(l:Set[T]) = (l map (v => implicitly[Json[T]].toJson(v))).mkString("[",",","]")
}

implicit def jsonMap[T:Json] = new Json[Map[String,T]] {
 def toJson(m:Map[String,T]) = (m map { case (k,v) =>
  s""""$k":${implicitly[Json[T]].toJson(v)}""" }).mkString("{",",","}")
}

def json[T:Json](v:T) = implicitly[Json[T]].toJson(v)

println(json("a"))
println(json(42))
println(json(Set("a","b")))
println(json(Map("k1" -> Set("a","b"))))