Shorten oop again

Author: matterche

src/main/worksheets/c_oop/a_intro_1_class_definition.sc

@@ -1,13 +1,13 @@
 /**
  * Scala is object-oriented and it's always like...write less do more :)
  */
-class DumpClass
+class AClass
 
-val d = new DumpClass
+val d = new AClass
 
 val isAny = d.isInstanceOf[Any]
 
-class AnotherDumpClass extends DumpClass
+class BClass extends AClass
 
-val isDump = new AnotherDumpClass().isInstanceOf[DumpClass]
-val isAnotherDump = new AnotherDumpClass().isInstanceOf[AnotherDumpClass]
+val isA = new BClass().isInstanceOf[AClass]
+val isB = new BClass().isInstanceOf[BClass]

src/main/worksheets/c_oop/a_intro_2_fields_methods.sc

@@ -3,13 +3,12 @@ import scala.util.Random
 /**
  * Class with field and methods
  */
-class LunchDecision {
-  // a private member
-  private val choices: Seq[String] = Seq("Pizza", "Sushi", "Burger")
+class Lunch {
+  private val where = Seq("Pizza", "Sushi", "Burger")
+
+  // Public API should have return type
+  def decide(): String = where(Random.nextInt(where.size))
 
-  // Type inference: remove return type
-  // syntactic sugar: remove curly braces
-  def decide() = choices(Random.nextInt(choices.size))
 }
 
-val lunch: String = new LunchDecision().decide()
+val lunch = new Lunch().decide()

src/main/worksheets/c_oop/a_intro_9_all.sc

@@ -1,29 +1,28 @@
-import scala.util.Random
-
 /**
  * Scala is object-oriented and it's always like...write less do more :)
  */
-class DumpClass
+class AClass
 
-val d = new DumpClass
+val d = new AClass
 
 val isAny = d.isInstanceOf[Any]
 
-class AnotherDumpClass extends DumpClass
+class BClass extends AClass
 
-val isDump = new AnotherDumpClass().isInstanceOf[DumpClass]
-val isAnotherDump = new AnotherDumpClass().isInstanceOf[AnotherDumpClass]
+val isA = new BClass().isInstanceOf[AClass]
+val isB = new BClass().isInstanceOf[BClass]
+
+import scala.util.Random
 
 /**
  * Class with field and methods
  */
-class LunchDecision {
-  // a private member
-  private val choices: Seq[String] = Seq("Pizza", "Sushi", "Burger")
+class Lunch {
+  private val where = Seq("Pizza", "Sushi", "Burger")
+
+  // Public API should have return type
+  def decide(): String = where(Random.nextInt(where.size))
 
-  // Type inference: remove return type
-  // syntactic sugar: remove curly braces
-  def decide() = choices(Random.nextInt(choices.size))
 }
 
-val lunch: String = new LunchDecision().decide()
+val lunch = new Lunch().decide()

src/main/worksheets/c_oop/b_constructors_1_parameters.sc

@@ -5,11 +5,11 @@ import scala.util.Random
  *
  * @see [[scala.collection.Seq]]
  */
-class ConfigurableLunchDecision(choices: Seq[String]) {
-  def decide() = choices(Random.nextInt(choices.size))
+class Lunch(where: Seq[String]) {
+  def decide(): String = where(Random.nextInt(where.size))
 }
 
-val configured = new ConfigurableLunchDecision(
+new Lunch(
   Seq(
     "Pasta",
     "Curry Wurst",

src/main/worksheets/c_oop/b_constructors_2_auxiliary.sc

@@ -3,8 +3,8 @@ import scala.util.Random
 /**
  * Inheritance and Auxiliary constructors
  */
-class LimitedChoicesLunchDecision(choices: Seq[String]) {
-  def decide() = choices(Random.nextInt(choices.size))
+class Lunch(choices: Seq[String]) {
+  def decide(): String = choices(Random.nextInt(choices.size))
 
   //  Restriction:
   //    The primary constructor must be called from every other constructor
@@ -13,4 +13,4 @@ class LimitedChoicesLunchDecision(choices: Seq[String]) {
   }
 }
 
-val limited = new LimitedChoicesLunchDecision("Pasta", "Pizza").decide()
+new Lunch("Pasta", "Pizza").decide()

src/main/worksheets/c_oop/b_constructors_3_default_parameters.sc

@@ -3,8 +3,9 @@ import scala.util.Random
 /**
  * Named parameter and default value
  */
-class TolerantLunchDecision(choice1: String = "Pasta", choice2: String = "Pizza") {
+class Lunch(choice1: String = "Pasta", choice2: String = "Pizza") {
   def decide() = Seq(choice1, choice2)(Random.nextInt(2))
 }
 
-val tolerant = new TolerantLunchDecision(choice2 = "Burger").decide()
+// Audience: I want Burger instead of Pizza
+new Lunch(choice2 = "Burger").decide()

src/main/worksheets/c_oop/b_constructors_4_constraints.sc

@@ -2,13 +2,10 @@
 /**
  * Constructor with constraints
  */
-class NoPastaLunchDecision(val choice: String) {
+class NoPasta(val choice: String) {
   if (choice == "Pasta")
     throw new IllegalArgumentException("Oh no ... Pasta again!!!")
 }
 
-val noPasta = try {
-  new NoPastaLunchDecision("Pasta").choice
-} catch {
-  case e: IllegalArgumentException => new NoPastaLunchDecision("Pizza").choice
-}
+new NoPasta("Pizza")
+new NoPasta("Pasta")

src/main/worksheets/c_oop/b_constructors_5_val_var_override.sc

@@ -12,6 +12,7 @@ class Reservation(budget: Int, val restaurant: String, var howMany: Int) {
 
 val lunchReservation = new Reservation(250, "Il Ritrovo", 12)
 
+// TODO: think about audience interaction instead of documenting
 // TODO: add parameter with override
 
 // Without "val" or "var" we just define a parameter. Accessing a parameter does not work.

src/main/worksheets/c_oop/c_abstract_classes_1_definition.sc

@@ -1,10 +1,7 @@
-
 /**
  * Abstract class with field and methods
- *
- * [[https://en.wikipedia.org/wiki/Date_format_by_country]]
  */
-abstract class Date(val day: Int, val month: Int, val year: Int) {
+abstract class Date(day: Int, month: Int, year: Int) {
   def format: String
 }
 
@@ -13,4 +10,4 @@ class DMY(day: Int, month: Int, year: Int) extends Date(day, month, year) {
   override def format: String = s"$day-$month-$year"
 }
 
-val dmy = new DMY(1, 1, 1978).format
+new DMY(1, 1, 1978).format

src/main/worksheets/c_oop/c_traits_2_definition.sc

@@ -13,7 +13,7 @@ trait JsonAble {
  */
 class Date(val day: Int, val month: Int, val year: Int) extends JsonAble {
   // @formatter:off
-  def toJson =
+  def toJson:String =
     s"""
        |{
        |"year": "$year",

src/main/worksheets/c_oop/c_traits_3_method_name_clashes.sc

@@ -11,6 +11,7 @@ trait B {
 
 class C
 
+// Audience: What happens?
 val c = new C() with A with B {
   override def foo = super[A].foo
 }