game-of-life.rb

#!/usr/bin/ruby

class Board
	Alive = '🥓'
	Dead = '🥚'
	Neighbors = [[-1,-1], [0,-1], [1,-1], [-1,0], [1,0], [-1,1], [0,1], [1,1]]

Glider = <<_END
🥚🥓🥚
🥚🥚🥓
🥓🥓🥓
_END

LightweightSpaceship = <<_END
🥓🥚🥚🥓🥚
🥚🥚🥚🥚🥓
🥓🥚🥚🥚🥓
🥚🥓🥓🥓🥓
_END

	def initialize(w = 20, h = 20, seed = nil)
		@w = w
		@h = h
		@board = Array.new(h){Array.new(w){Dead}}
		@count = Array.new(h){Array.new(w)}
		if seed
			seed.split(/\n/).each_with_index do |line, r|
				line.scan(/./).each_with_index do |char, c|
					@board[r][c] = char
				end
			end
		else
			(@w * @h / 5).times do
				@board[Random.rand(@h)][Random.rand(@w)] = Alive
			end
		end
	end

	def neighbors(r, c)
		n = 0
		Neighbors.each do |dr, dc|
			n += 1 if @board[(r + dr) % @h][(c + dc) % @w] == Alive
		end
		return n
	end

	def step
		@h.times do |r|
			@w.times do |c|
				@count[r][c] = neighbors(r, c)
			end
		end
		changed = false
		@h.times do |r|
			@w.times do |c|
				if @board[r][c] == Alive
					if @count[r][c] < 2 or @count[r][c] > 3
						@board[r][c] = Dead
						changed = true
					end
				else	# Dead
					if @count[r][c] == 3
						@board[r][c] = Alive
						changed = true
					end
				end
			end
		end
		return changed
	end

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

b = Board.new(39, 24, Board::Glider + "\n"*10 + Board::LightweightSpaceship)

ClearScreen = "\u001b[2J"
MoveToHome = "\u001b[1;1H"
print ClearScreen
print MoveToHome
puts b
while b.step
	sleep 0.1
	print MoveToHome
	puts b
end