Data commit

Task/Langtons-ant/Scala/langtons-ant.scala

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+class Langton(matrix:Array[Array[Char]], ant:Ant) {
+  import Langton._
+  val rows=matrix.size
+  val cols=matrix(0).size
+	
+  def isValid = 0 <= ant.row && ant.row < cols && 0 <= ant.col  && ant.col < rows
+  def isBlack=matrix(ant.row)(ant.col)==BLACK
+  def changeColor(c:Char)={matrix(ant.row)(ant.col)=c; matrix}
+	
+  def evolve():Langton={
+    val (newCol, newAnt)=if(isBlack) (WHITE, ant.turnLeft) else (BLACK, ant.turnRight)
+    new Langton(changeColor(newCol), newAnt.move)
+  }
+  override def toString()=matrix map (_.mkString("")) mkString "\n"	
+}
+
+case class Ant(row:Int, col:Int, d:Int=0) {
+  def turnLeft=Ant(row,col,(d-1)&3)
+  def turnRight=Ant(row,col,(d+1)&3)
+  def move=d match {
+    case 0 => Ant(row-1,col,d)	// north
+    case 1 => Ant(row,col+1,d)	// east
+    case 2 => Ant(row+1,col,d)	// south
+    case 3 => Ant(row,col-1,d)	// west
+  }
+}
+
+object Langton {
+  val BLACK='#'
+  val WHITE='.'
+  def apply(x:Int=100, y:Int=100)=new Langton(Array.fill(y, x)(WHITE), Ant(x>>>1, y>>>1, 0))
+	
+  def main(args: Array[String]): Unit = {
+    var l=Langton(100,100)
+    var moves=0
+    while (l.isValid) {
+      moves += 1
+      l=l.evolve
+    }
+    println("Out of bounds after "+moves+" moves")
+    println(l)
+  }
+}