Conway's Game of Life written in Swift, except classes; ported from https://gist.github.com/thara/ded6dd880ba95580088ef8875abb05e5

lifegame.swift

import Foundation

let height = 30
let width = 60

struct Point : Hashable {
    var x: Int
    var y: Int
}

func neighbers(around point: Point) -> [Point] {
    let x = point.x
    let y = point.y
    return [
            (x - 1, y - 1), (x , y - 1), (x + 1, y - 1),
            (x - 1, y    ),              (x + 1, y    ),
            (x - 1, y + 1), (x , y + 1), (x + 1, y + 1),
            ].map(Point.init)
}

func living(at point: Point, in board: Set<Point>) -> Bool {
    let count = neighbers(around: point).filter { board.contains($0) }.count
    return count == 3 || (count == 2 && board.contains(point))
}

func advance(board: Set<Point>) -> Set<Point> {
    let recalc = board.union(board.flatMap(neighbers))
    return Set(recalc.filter { living(at: $0, in: board) })
}

func printBoard(_ board: Set<Point>) {
    for y in 0..<height {
        for x in 0..<width {
            let mark = board.contains(Point(x: x, y: y)) ? "*" : "-"
            print(mark, terminator: "")
        }
        print("")
    }
}

var state = Set([(0, 1), (1, 2), (2, 0), (2, 1), (2, 2)].map(Point.init))
printBoard(state)

while true {
    usleep(100 * 1000)
    print("\u{1b}[\(height)A\r", terminator: "")

    state = advance(board: state)
    printBoard(state)
}