From: Daniel Moore <yahivin@...>
Date: 2009-02-28T12:39:26+09:00
Subject: Re: [QUIZ] Game of Life (#193)

> ## Game of Life (#193)

It's about time I solve one of my own quizzes! My solutions only goal
was to teach me how to user Fibers in 1.9. Fibers are definitely worth
puzzling over. Reading about them is fine but you won't really get
that "Aha!" moment until you start using them.

Quiz summary coming tomorrow. Thanks everyone for your participation this week!

#!/usr/bin/ruby1.9

class Cell < Fiber
  def initialize
    super do
      alive = rand(2) == 1

      loop do
        neighbors = Fiber.yield(alive)
        if(alive)
          alive = ((2..3) === neighbors)
        else
          alive = (3 == neighbors)
        end
        Fiber.yield(alive)
      end
    end

    @alive = resume
  end

  def step
    @alive = resume
  end

  def set_neighbors(neighbors)
    resume(neighbors)
  end

  def alive?
    @alive
  end

  def to_s
    alive? ? '0' : '.'
  end
end

class Life
  def initialize(width=5, height=5)
    @width, @height = width, height
    @board = Array.new(height) {Array.new(width) {Cell.new}}
  end

  def step
    @board.each_with_index do |row, y|
      row.each_with_index do |cell, x|
        cell.set_neighbors(alive_neighbours(y, x))
      end
    end

    @board.each{|row| row.each{|cell| cell.step }}
  end

  # Based on code by Andrea Fazzi
  def alive_neighbours(y, x)
    [[-1, -1], [0, -1], [1, -1], [1, 0], [1, 1], [0, 1], [-1, 1], [-1,
0]].inject(0) do |sum, cell|
      sum += @board[(y + cell[0])%@height][(x + cell[1])%@width].alive? ? 1 : 0
    end
  end

  def to_s
    @board.map{|row| row.join('')}.join("\n")
  end
end

game = Life.new(30, 30)

250.times do
  game.step
  #puts game.counts
  puts game
end


-- 
-Daniel
http://strd6.com