gistfile1.scala

object App {

  case class Post(title: String,
                  body: String,
                  tags: List[String])
  case class Address(street: String,
                     city: String,
                     state: String,
                     zip: String,
                     tags: List[String])

  type Taggable = { def tags: List[String] }

  def formattedTags(taggable: Taggable) = {
    taggable.tags.mkString(",")
  }

  def main(args: Array[String]) {
    val post = Post("Weekly NFL Scores",
                    "This week...",
                    List("news", "sports", "local"))
    println(formattedTags(post))    // news,sports,local

    val address = Address("1 Main St.",
                          "Anytown",
                          "CA",
                          "12345",
                          List("home", "work"))
    println(formattedTags(address)) // home,work
  }
}