/*
 * Copyright (C) 2007-2019 Artima, Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Automatically generated Scala interpreter transcript from:
 *
 * Programming in Scala (Fourth Edition)
 * by Martin Odersky, Lex Spoon, Bill Venners
 *
 * http://booksites.artima.com/programming_in_scala_4ed
 */


scala>   abstract class Element {
           def contents: Array[String]
           val height = contents.length
           val width = 
             if (height == 0) 0 else contents(0).length
         }

defined class Element

scala>   class ArrayElement(conts: Array[String]) extends Element {
           def contents: Array[String] = conts
         }

defined class ArrayElement

scala> val ae = new ArrayElement(Array("hello", "world"))
ae: ArrayElement = ArrayElement@7d8b66d9

scala> ae.width
res0: Int = 5

scala>   abstract class Element {
           def demo() = {
             println("Element's implementation invoked")
           }
         }
       
         class ArrayElement extends Element {
           override def demo() = {
             println("ArrayElement's implementation invoked")
           }
         }
       

          class LineElement extends ArrayElement {
           override def demo() = {
             println("LineElement's implementation invoked")
           }
         }
       

          // UniformElement inherits Element's demo
         class UniformElement extends Element 

defined class Element
defined class ArrayElement
defined class LineElement
defined class UniformElement

scala>   def invokeDemo(e: Element) = {
           e.demo()
         }

invokeDemo: (e: Element)Unit

scala> invokeDemo(new ArrayElement)
ArrayElement's implementation invoked

scala> invokeDemo(new LineElement)
LineElement's implementation invoked

scala> invokeDemo(new UniformElement)
Element's implementation invoked

scala>   class ArrayElement extends Element {
           final override def demo() = {
             println("ArrayElement's implementation invoked")
           }
         }

defined class ArrayElement

scala>   class LineElement extends ArrayElement {
           override def demo() = {
             println("LineElement's implementation invoked")
           }
         }
       

                  override def demo() = {
                               ^
On line 2: error: cannot override final member:
       final override def demo(): Unit (defined in class ArrayElement)

scala>   final class ArrayElement extends Element {
           override def demo() = {
             println("ArrayElement's implementation invoked")
           }
         }

defined class ArrayElement

scala>   class LineElement extends ArrayElement {
           override def demo() = {
             println("LineElement's implementation invoked")
           }
         }
       

                                   ^
       error: illegal inheritance from final class ArrayElement

scala>   Array(1, 2, 3) zip Array("a", "b")

res4: Array[(Int, String)] = Array((1,a), (2,b))