1. Case Classes in Scala Intro
UMBC
CMSC 331

2. Basic Properties
Case classes are regular classes which export their constructor parameters and which provide a recursive decomposition mechanism via pattern matching.

3. Example abstract class Term case class Var(name: String) extends Term
case class Fun(arg: String, body: Term) extends Term
case class App(f: Term, v: Term) extends Term

4. Code Code Example Fun("x", Fun("y", App(Var("x"), Var("y"))))
For every case class the Scala compiler generates equals method which implements structural equality and atoString method. For instance and so ...
Fun("x", Fun("y", App(Var("x"), Var("y"))))

5. Results val x1 = Var("x") val x2 = Var("x") val y1 = Var("y")
println("" + x1 + " == " + x2 + " => " + (x1 == x2))
println("" + x1 + " == " + y1 + " => " + (x1 == y1))
Var(“x”) == Var(“x”) =>true
Var(“x”) == Var(“y”) => false

6. Another Example abstract class IntTree
case class Empty() extends IntTree
case class Node(value: Int,
left: IntTree,
right:IntTree) extends IntTree

7. References A tour of Scala : Traits (see http://www.scala-lang.org)
Programming in Scala, Martin Odersky et al, Artima press 2009
Beginning Scala, David Pollak, Apress, 2009