The document discusses Scala programming concepts including object-oriented programming, functional programming, collections, pattern matching, and more. It provides code examples of defining objects and classes, functions, for expressions, match expressions, case classes, traits, generics, and collections like List and Map.

1. <moriyoshi@gmail.com>

4. Java 1.5
Pizza GJ
Scala
Funnel

7. public class Application {
public static void main(String[] args) {
System.out.println(”Hello, World”);
}
}
object Application {
def main(args: Array[String]) {
println(”Hello, World”)
}
}

8. //
val numbers = 1.until(10) // 1, 2, ..., 10
println(numbers(5)) // ”6”
//
println((5).+(3)) // ”8”
println(5 + 3) // ”()” ”.”
println(5.+(3)) // 5.0+(3)
//
println(1 until 10)

9. //
// (?)

10. // String Unit
// println puts
val puts: String => Unit = println
puts(”hey!”)
def fun1(x: Int): Int = {
def fun2(y: Int): Int = x * y
fun2(5) //
}
val fun3 = (z: Int) => fun1(z + 2)
fun3(3) // 25

11. def matcher(l: List[Int]): Int = l match {
case List(1, 2) => 1
case List(2, 3) => 2
case _ => 0
}
val l = for {
i <- List(1, 2, 3, 4)
if (i > 1)
} yield i // List(2, 3, 4)
l = [1, 2, 3, 4].find_all {|i| i > 1}
l = [i for i in (1, 2, 3, 4) if (i > 1)]

13. object Application {
def main(args: Array[String]) {
println(”Hello, ” + args(0))
}
}
scalac
$ scalac Application.scala
scala
$ scala -cp . Application

14. object Application {
def main(args: Array[String]) {
println(”Hello, ” + args(0))
}
}
def
: , : , ...
+
Array[ ]
[] ()

15. object Application {
def main(args: Array[String]) {
println(”Hello, ” + args(0))
}
}
object
class
println

16. ‣ object
class
object
final class Application$cls
private var Application$instance = null
final def Application = {
if (Application$instance == null)
Application$instance = new Application$cls
return Application$instance
}

17. ‣ println
object
import Scala.Predef._

19. 123 0x123 0123 456L
123.0 13e-8 5e-35D
true false
’A’ ’ ’ ’u0041’
”howdyn” ””ahoy””
”””I think ”Scala” is great”””
(1, 2, 3)
<foo>bar</foo>

20. val var
var val : =
val

21. val str: String = ”hey”
val i = 123 //
val f = 5.0
val longstr = ”””test”test”””
val tuple = (1, 2, 3)
val xml =
<property>
<name>prop</name>
<value>{longstr}{tuple(0)}</value>
</property>

23. Any
AnyVal AnyRef
Unit ScalaObject Java
Boolean Char
Byte Short ... ...
Int Long ... ...
Float Double ... ...
Null
Nothing

24. asInstanceOf[ ]
isInstanceOf[ ]

25. class {
}
class extends {
}
class extends
with ... {
}
private class ... {}
protected class ... {}
sealed class ... {}
abstract class ... {}
final class ... {}

26. object {
}
object extends {
}
object extends
with ... {
}
private object ... {}
protected object ... {}

27. trait {
}
trait extends
with ... {
}
trait extends
with ... {
}
private trait ... {}
protected trait ... {}
sealed trait ... {}

29. public protected
private sealed
sealed
abstract

30. class ( ) {
val =
var =
protected val|var ...
private val|var ...
def this ...
def
private def ...
protected def ...
}

31. def ( ) =
def ( ): =
def ( ) {...}
: , : , ...

32. class Foo {
private var prop_: Int = 0
def prop = prop_
def prop_=(value: Int) = { prop_ = value }
}
_=
val f: Foo = new Foo
f.prop = 123 // prop_=()

34. def this

35. class Foo {
def this(i: Int) = {
this()
... ...
}
}
class Bar(param1: Double) {
val param1sq = param1 * param1
def this(strParam: String) = {
this(strParam.toDouble)
}
}

36. trait Named {
private var name_ = quot;quot;
def name = name_
def name_=(v: String) = { name_ = v }
}
class Person(firstName: String,
lastName: String)
extends AnyRef with Named {
name = firstName + quot; quot; + lastName
}
trait SuperMonkeys {
val reina = new Person(quot;Reinaquot;, quot;Miyauchiquot;)
val lina = new Person(quot;Ritsukoquot;, quot;Matsudaquot;)
val mina = new Person(quot;Minakoquot;, quot;Amahisaquot;)
val nana = new Person(quot;Nanakoquot;, quot;Takushiquot;)
}
// extends
class with SuperMonkeys {
}

38. [ , ...]
[ , ...]

39. class MyArrayList[T] {
private var elems_ = new Array[T](1)
private var size_ = 0
def size = size_
def get(index: Int): T = {
if (index < 0 || index >= size_)
throw new IndexOutOfBoundsException()
elems_(index)
}
def append(elem: T): Unit = {
if (size_ >= elems_.length) {
val newElems = new Array[T](elems_.length * 2)
Array.copy(elems_, 0, newElems, 0, elems_.length)
elems_ = newElems
}
elems_(size_) = elem
size_ += 1 var mal = MyArrayList[String]()
} mal.append(”hoge”)
} mal.append(”fuga”)
println(mal.get(0)) // hoge
println(mal.get(1)) // fuga

40. match {
case =>
case =>
case =>
}

41. case class
_

42. class Card {}
trait Colored {
val color: String
}
case class NumberedCard(color: String,
number: Int)
extends Card with Colored {}
case class WildCard extends Card {}
case class DrawTwo(color: String)
extends Card with Colored {}
case class DrawFour extends Card {}
def putCard = this.discarded match {
case NumberedCard(color, number) => 1
case WildCard(color) => 2
case DrawTwo(color) => 3
case DrawFour(color) => 4
}

43. for ( <- Iterable) {
... ...
}

44. for (a <- (1, 2, 3, 4)) {
println(a)
}
//
for (a <- (1, 2, 3, 4);
b <- (1, 2, 3, 4)) {
println(a)
println(b)
}

45. var result = List[Int]()
for (i <- List(1, 2, 3, 4)) {
result += (i * i)
}
val result = for (i <- List(1, 2, 3, 4))
yield i * i

49. val (a, b, c) = (1, 2, 3)
var l = List(1, 2, 3) // val
l += 4
println(l) // 1, 2, 3, 4
import scala.collection.mutable._
val l = new ListBuffer[Int]()
l ++= List(1, 2, 3, 4)
l += 5
println(l) // 1, 2, 3, 4, 5

52. var dict = Map(
(”apple”, 100),
(”microsoft”, 200),
(”banana”, 300)
)
dict -= ”microsoft”
// ”apple” -> 100, ”banana” -> 300
println(dict)