A basic Singly Linked List in Kotlin

SinglyLinkedList.kt

package prydt.source // just a package, m8

/**
 * Created by PryDt on 6/13/2017.
 */

// basic node on list
data class Node<T>(var key: T?, var next: Node<T>?)

// the list class
class SinglyLinkedList<T>
{
    // the start of the list
    var root = Node<T>(null, null)

    // the length of the list
    var length = 0

    // add a node to the end of the list
    fun push(key: T){
        var node = Node(key, null)
        var ptr = root

       if(ptr.equals(Node<T>(null, null)))
       {
           ptr.key = key
           length++
           return
       }

        while(ptr.next != null)
            ptr = ptr.next!!

        ptr.next = node
        length++
    }

    // checking whether a certain value is in the list
    fun search(key: T): Boolean {
        var ptr = root
        while(ptr.key != key && ptr.next != null)
            ptr = ptr.next!!
        return (ptr.key == key)
    }

    // returns the length of the list
    inline fun size() = length

    // prints out list to stdout
    fun printList() {
        print("[ ")

        var ptr = root
        while(ptr.next != null)
        {
            print("${ptr.key} -> ")
            try {
                ptr = ptr.next!!
            }catch (e: Exception)
            {
            }
        }
        println("null ]")
        println("Length of List: ${size()}, null doesn't count")
    }
}