Dwarf v0.1.0

-- Dwarf - THE BEST ULTIMATE DIGGER EVER
--        ---   v0.1.0    ---
--               * * *
-- I am a dwarf, and I'm digging a hole!
-- Diggy diggy hole, diggy diggy hole!
--               * * *

local robot = require("robot")
local sides = require("sides")
local com = require("component")
local r = com.robot

-- parse commandline arguments
local args = {...}
local WIDTH, HEIGHT, DEPTH = tonumber(args[1]), tonumber(args[2]), tonumber(args[3])
if type(WIDTH) ~= "number" or type(HEIGHT) ~= "number" or type(DEPTH) ~= "number" then
    print("SYNTAX: dwarf <width> <height> <depth>")
  os.exit()
end

-- failsafe navigation
local pos = { x = 0, y = 0, z = 0, t = 0 }
function pos.forward()
  if pos.t == 0 then pos.x = pos.x + 1
  elseif pos.t == 1 then pos.z = pos.z + 1
  elseif pos.t == 2 then pos.x = pos.x - 1
  else pos.z = pos.z - 1 end
end
function pos.up() pos.y = pos.y + 1 end
function pos.down() pos.y = pos.y - 1 end
function pos.move(side)
  if side == sides.forward then pos.forward(); return true
  elseif side == sides.up then pos.up(); return true
  elseif side == sides.down then pos.down(); return true
  else return false end
end
function pos.left() pos.t = (pos.t + 3) % 4 end
function pos.around() pos.t = (pos.t + 2) % 4 end
function pos.right() pos.t = (pos.t + 1) % 4 end
function pos.reset() pos.x = 0; pos.y = 0; pos.z = 0; pos.t = 0 end

local function left()
  robot.turnLeft()
  pos.left()
end
local function around()
  robot.turnAround()
  pos.around()
end
local function right()
  robot.turnRight()
  pos.right()
end

-- digging mode
local mode, VOID, SOLID = nil, {}, {}
function VOID.move(side)
  if r.move(side) then pos.move(side); return true
  else mode = SOLID end
  return false
end
function SOLID.move(side)
  if r.swing(side) then
    if r.move(side) then pos.move(side); return true end
  else mode = VOID end
  return false
end

local function forward()
  while not mode.move(sides.forward) do end
end
local function up()
  while not mode.move(sides.up) do end
end
local function down()
  while not mode.move(sides.down) do end
end

-- go!
mode = SOLID

local a, b = true, true
while true do
  for x = 1, DEPTH - 1 do forward(); os.sleep(0.1) end
  if (b and pos.z < WIDTH - 1) or (not b and pos.z > 0)  then
    if a then right(); forward(); right()
    else left(); forward(); left() end
    a = not a
  else
    if pos.y > -HEIGHT + 1 then
      down(); around(); b = not b
    else break end
  end
end

-- the end