Simple persistent (single-linked) list implemented with Kotlin

PList.kt

package core

open class PList<T>(val value: T, val next: PList<T>?) : Iterable<T> {

  override fun iterator() = object : Iterator<T> {
    var PList: PList<T>? = this@PList
    override fun hasNext() = PList != null
    override fun next() = PList!!.value.also { PList = PList!!.next }
  }

}