TypeInfo pickling

tagged.scala

package tagged

import scala.pickling._
import internal._
import json._


// final case class TypeInfo(erasureClass: String, typeArguments: Seq[TypeInfo] = Seq.empty)
// final case class AttributeKey(name: String, manifest: TypeInfo)


object TaggedPicklers extends App {

  
  case class Tagged[A: FastTypeTag](key: String) {
    // type string of Tagged[A]
    val typeString: String = implicitly[FastTypeTag[A]].key
    val appliedType: AppliedType = AppliedType.parse(typeString)._1
  }


  implicit def taggedPickler[A: Manifest: FastTypeTag]: SPickler[Tagged[A]] with Unpickler[Tagged[A]] =
    new SPickler[Tagged[A]] with Unpickler[Tagged[A]] {

    def pickle(picklee: Tagged[A], builder: PBuilder): Unit = {
      builder.beginEntry(picklee)

      builder.putField("key", b => {
        b.hintTag(FastTypeTag.String)
        b.hintStaticallyElidedType()
        SPickler.stringPicklerUnpickler.pickle(picklee.key, b)
      })

      builder.endEntry()
    }

    def unpickle(tag: => FastTypeTag[_], reader: PReader): Any = {
      val reader1 = reader.readField("key")
      reader1.hintTag(FastTypeTag.String)
      reader1.hintStaticallyElidedType()

      val tag1 = reader1.beginEntry()
      val key = SPickler.stringPicklerUnpickler.unpickle(tag1, reader1)
      reader1.endEntry()

      Tagged[Any](key.asInstanceOf[String])(tag.asInstanceOf[FastTypeTag[Any]])
    }
  }


  val t = Tagged[List[Int]]("favNums")
  val p = t.pickle

  println(p.value)

  val up = p.unpickle[Tagged[Any]]
  println(up.appliedType)

}