[OpenComputers] Elementary Cellular Automata

-- eca.lua <rule_number> <1/2>
local rule = 22
local r, tn = math.random, tonumber
local gpu = require("component").gpu
local w, h = gpu.getResolution()
local tWorld, tBuffer, tRule = {}, {}, {}
local tArgs = {...}

local function set(a)
  if a == 1 then
    for i = 1, w do tWorld[i] = 0 end
    tWorld[math.floor(w/2)] = 1
  elseif a == 2 then
    for i = 1, w do tWorld[i] = r(0, 1) end
  end
end

local function dot(x, y, color)
  local n = y%2
  y = (y+n)/2
  local c, Fc, Bc = gpu.get(x, y)
  local c1, Fc1, Bc1 = c, Fc, Bc
  if c ~= "▄" then Fc = Bc end
  if n == 0 then Fc = color else Bc = color end
  if Fc1 ~= Fc or Bc1 ~= Bc1 then
    gpu.setForeground(Fc)
    gpu.setBackground(Bc)
    gpu.set(x, y, "▄")
  end
end

if #tArgs == 2 then
  rule = tn(tArgs[1])
  set(tn(tArgs[2]))
else
  set(2)
end

for m = 0, 7 do tRule[m] = bit32.extract(rule, m) end
gpu.fill(1, 1, w, h, " ")
for j = 1, h*2 do
  tWorld, tBuffer = {table.unpack(tBuffer)}, {table.unpack(tWorld)}
  for x = 1, #tWorld do
    if tWorld[x] == 1 then
      dot(x, j-1, 65280)
    end
  end
  for i = 1, #tWorld do
    if tWorld[i-1] and tWorld[i+1] then
      tBuffer[i] = tRule[tn(tWorld[i-1]..tWorld[i]..tWorld[i+1], 2)]
    elseif not tWorld[i-1] then
     tBuffer[i] = tRule[tn(tWorld[#tWorld]..tWorld[i]..tWorld[i+1], 2)]
    elseif not tWorld[i+1] then
      tBuffer[i] = tRule[tn(tWorld[i-1]..tWorld[i]..tWorld[1], 2)]
    end
  end
  os.sleep()
end
gpu.setBackground(0)
gpu.setForeground(0xFFFFFF)