Game of life: Implementation for generations

Author: Heiko Seeberger

src/main/scala/Generation.scala

@@ -1,5 +1,23 @@
 case class Generation(aliveCells: Set[Cell] = Set.empty) {
 
  def next: Generation =
- ???
+ new Generation(stayingAlive ++ born)
+
+ def stayingAlive: Set[Cell] =
+ aliveCells.filter(canStayAlive)
+
+ def born: Set[Cell] =
+ aliveCells.flatMap(deadNeighbors).filter(canBeBorn)
+
+ def canStayAlive(cell: Cell): Boolean =
+ Set(2, 3).contains(aliveNeighbors(cell).size)
+
+ def canBeBorn(cell: Cell): Boolean =
+ aliveNeighbors(cell).size == 3
+
+ def aliveNeighbors(cell: Cell): Set[Cell] =
+ cell.neighbors.intersect(aliveCells)
+
+ def deadNeighbors(cell: Cell): Set[Cell] =
+ cell.neighbors.diff(aliveCells)
 }