seven languages in seven weeks : scala day 1

Board.scala

package info.denoo.slisw.tictactoe

/**
 * A representation of the gameboard.
 */
class Board() {
  val cells = Array.fill(3, 3) {
    new TicTacToeCell()
  }

  def printBoard() {
    for (line <- cells) {
      for (cell <- line){
        print(cell.toString)
      }
      println();
    }
  }

  def noMoreOptions() : Boolean = {
    for (line <- cells) {
      for (cell <- line){
        if (cell.sign == Sign.Blank){
          return false
        }
      }
    }
    true
  }

  def checkRows: Option[Status.Status] = {
    for (line <- cells) {
      println(line)
      if (line(0).sign == line(1).sign && line(0).sign == line(2).sign) {
        if (line(0).sign != Sign.Blank) {
          return Some(winner(line(0).sign))
        }
      }
    }
    None
  }

  def checkColumns: Option[Status.Status] = {
    for (i <- 0 to 2) {
      if (cells(0)(i).sign == cells(1)(i).sign && cells(0)(i).sign == cells(2)(i).sign) {
        if (cells(0)(i).sign != Sign.Blank) {
          return Some(winner(cells(0)(i).sign))
        }
      }

    }
    None
  }

  def checkDiagonals: Option[Status.Status] = {
    if (cells(0)(0).sign == cells(1)(1).sign && cells(0)(0).sign == cells(2)(2).sign) {
      if (cells(0)(0).sign != Sign.Blank) {
        return Some(winner(cells(0)(0).sign))
      }
    }

    if (cells(0)(2).sign == cells(1)(1).sign && cells(0)(2).sign == cells(2)(0).sign) {
      if (cells(0)(2).sign != Sign.Blank) {
        return Some(winner(cells(0)(2).sign))
      }
    }
    None
  }

  def status() : Status.Status = {
    println("in status")
    if (noMoreOptions()){
      return Status.DRAW
    }
    checkRows match {
      case Some(x) => return x
      case None =>
    }

    checkColumns match {
      case Some(x) => return x
      case None =>
    }

    checkDiagonals match {
      case Some(x) => return x
      case None =>
    }

    Status.CONTINUE
  }

  def winner(sign : Sign.Sign) : Status.Status = {
    if (sign == Sign.X){
      Status.WINNER_X
    }else {
      Status.WINNER_O
    }
  }

  def placeSign(x : Int,  y : Int,  sign : Sign.Sign) = {
    if (cells(x)(y).sign == Sign.Blank){
      cells(x)(y).sign = sign
    }
  }


}

Player.scala

package info.denoo.slisw.tictactoe

/**
 * Representation of the players in the TicTacToe Game.
 */
case class Player(val name :String, val sign:Sign.Sign) {

}

Sign.scala

package info.denoo.slisw.tictactoe

/**
 * The sign, can be Blank for blank cells, and X or O for the others.
 */
object Sign extends Enumeration{
  type Sign = Value
  val Blank, X, O = Value
}

Status.scala

package info.denoo.slisw.tictactoe

/**
 * The status of the game board.
 */
object Status extends Enumeration {
  type Status = Value
  val WINNER_X, WINNER_O, CONTINUE, DRAW = Value
}

TicTacToeCell.scala

package info.denoo.slisw.tictactoe

class TicTacToeCell {
   var sign = Sign.Blank

   override def toString(): String = sign match {
     case Sign.Blank => "_"
     case Sign.X => "X"
     case Sign.O => "O"
   }
}

TicTacToeGame.scala

package info.denoo.slisw.tictactoe

/**
 * A Simple TicTacToe game for 2 players that ask for input.
 */
object TicTacToeGame {
  val player1: Player = new Player("player1", Sign.X)
  val player2: Player = new Player("player2", Sign.O)
  val players = Array(player1, player2)

  def createBoard(): Board = {
    new Board()
  }

  def getInput: Int = {
    Console.readInt()
  }

  def main(args: Array[String]) = {
    val board = createBoard();
    var playerNr = 0
    while (board.status() == Status.CONTINUE) {

      println(players(playerNr).name + " your move? (1-9 )")
      val move = getInput

      val x: Int = (move - 1) / 3
      val y: Int = (move - 1) % 3

      board.placeSign(x, y, players(playerNr).sign)

      playerNr = (playerNr + 1) % 2
      board.printBoard()
    }
    printResult(board)
  }


  def printResult(board: Board) {
    if (board.status() == Status.DRAW) {
      println("it is a draw")
    } else {
      println("The winner is  " + winner(board.status()))
    }
  }

  def winner(status: Status.Status): String = {
    if (status == Status.WINNER_X) {
      player1.name
    }else{
      player2.name
    }
  }

}

The following code

override def toString(): String = {
  if (sign == Sign.Blank) {
    return "_"
  } else if (sign == Sign.X) {
    return "X"
  } else {
    return "O"
  }
}

can be written as:

override def toString(): String = sign match {
  case Sign.Blank => "_"
  case Sign.X => "X"
  case Sign.O => "O"
}

You can write:

for (line <- cells) {
  for (cell <- line){
    if (cell.sign == Sign.Blank){
      return false
    }
  }
}
true

as:

! (cells exists (_ exists (_.sign == Sign.Blank)))

I can recommend the docs at http://www.scala-lang.org/docu/files/collections-api/collections.html for more tricks like this.

thanx erik, I finally updated the code with your tips.
I won't put it the last one, cause at this point in the book it is just the oo part of scala, collections and functional programming will be in the next chapters.