Marcus Bengtsson revised this on 14 May 2018

GameOfLife.scala

object GameOfLife extends App { case class Point(x: Int, y: Int) type World = Set[Point] val startingWorld = Set(Point(0, 0), Point(0, 1), Point(0, -1), Point(1, 0), Point(-1, 0)) allGenerations(startingWorld).take(10).map(worldToString).foreach(println) def allGenerations(w: World) = Stream.iterate(w)(nextGeneration).takeWhile(_.nonEmpty) def nextGeneration(w: World) = w.flatMap(nearbyCluster).filter(isAlive(_, w)) def nearbyCluster(p: Point) = for { x: Int <- (p.x - 1 to p.x + 1).toSet y: Int <- (p.y - 1 to p.y + 1).toSet } yield Point(x, y) def isAlive(p: Point, w: World) = rules(w.contains(p), neighbourCount(p, w)) def rules(alive: Boolean, nc: Int) = nc == 3 || (alive && nc == 2) def neighbourCount(p: Point, w: World) = nearbyCluster(p).intersect(w).filterNot(p.equals).size def worldToString(w: World) = (w.map(_.y).max to w.map(_.y).min by -1) .map(y => (w.map(_.x).min to w.map(_.x).max) .map(x => if (w.contains(Point(x, y))) 'x' else '.')) .map(_.mkString(" ")) .mkString("\n") + "\n" }