coderetreat wpg

game_of_life.rb

class Cell

end

class World
  def initialize
    @x = 50
    @y = 50
  end

  def set(x, y, cell = Cell.new)
    cell(x, y, cell)
    self
  end

  def cell(x, y, cell = Cell.new)
    @grid[x][y] = cell unless at(x,y)
  end

  def at(x,y)
    @grid ||= {}
    @grid[x] ||= {}
    @grid[x][y]
  end

  def neighbours(x,y)
    [
      at(x - 1, y - 1),
      at(x - 1, y    ),
      at(x - 1, y + 1),
      at(x    , y - 1),
      at(x    , y + 1),
      at(x + 1, y - 1),
      at(x + 1, y    ),
      at(x + 1, y + 1),
    ].compact
  end

  def next
    w = World.new
    @grid.each do |x, h|
      @h.each do |y, c|
        if cell = at(x,y)
          case neighbours(x,y).size
          when 2..3: w.cell(x,y, cell)
          else
            # do nothing
          end
        else
          case neighbours(x,y).size
          when 3: w.cell(x,y, Cell.new)
          else
            # do nothing
          end
        end
      end
    end
    w
  end

  def to_s
    col = []
    @x.times do |x|
      row = []
      @y.times do |y|
        row += [at(x,y) ? '#':'.', ' ']
      end
      col << row.join()
    end
    col
  end

end

# 0 1 2
#
# 1 1 0
# 1 0 0
# 0 0 0
#
# 1 1 0
# 1 1 0
# 0 0 0
#


if $0 == __FILE__
  world = World.new.
    set(0,2).
    set(1,2).
    set(2,2).
    set(1,0).
    set(2,1).

    set(10 + 0,2).
    set(10 + 1,2).
    set(10 + 2,2).
    set(10 + 1,0).
    set(10 + 2,1).

    set(30,30).
    set(30,31).
    set(30,32)

  loop do
    print "\e[2J\e[f"
    puts world.to_s
    world = world.next
  end
else 

  describe "World" do
    it 'should have cell' do 
      world = World.new
      cell = world.cell(1,2)
      world.at(1,2).should == cell
    end

    it 'shoudl have no neighbours' do
      world = World.new
      cell = world.cell(1,2)
      world.neighbours(1,2).should == []
    end

    it 'shoudl have neighbours' do
      world = World.new
      cell = world.cell(1,2)
      neigbour = world.cell(1,1)
      world.neighbours(1,2).should == [neigbour]
    end
  end

  describe "Evolution" do
    before :each do
      @world = World.new
      @world.cell(0,0)
      @world.cell(0,1)
      @world.cell(1,0)
    end

    it 'should spawn' do
      world = @world.next
      world.at(1,1).should be_a(Cell)
    end
  end
end