turtle

local s = turtle.select
local f = turtle.forward
local b = turtle.back
local l = turtle.turnLeft
local r = turtle.turnRight
local u = turtle.up
local d = turtle.down

local function select(num)
  if num == nil then
    return turtle.slot
  else
    rawset(turtle, "slot", num)
    return s(num)
  end
end
local function forward()
  if f() then
    rawset(turtle, "x", turtle.x + turtle.dirX)
    rawset(turtle, "z", turtle.z + turtle.dirZ)
    return true
  end
  return false
end
local function back()
  if b() then
    rawset(turtle, "x", turtle.x - turtle.dirX)
    rawset(turtle, "z", turtle.z - turtle.dirZ)
    return true
  end
  return false
end
local function left()
  local dirX, dirZ = turtle.dirZ, -turtle.dirX
  rawset(turtle, "dirX", dirX)
  rawset(turtle, "dirZ", dirZ)
  return l()
end
local function right()
  local dirX, dirZ = -turtle.dirZ, turtle.dirX
  rawset(turtle, "dirX", dirX)
  rawset(turtle, "dirZ", dirZ)
  return r()
end
local function up()
  if u() then
    rawset(turtle, "y", turtle.y + 1)
    return true
  end
  return false
end
local function down()
  if d() then
    rawset(turtle, "y", turtle.y - 1)
    return true
  end
  return false
end
local function loc()
  return turtle.x, turtle.y, turtle.z
end
local function dir()
  return turtle.dirX, turtle.dirZ
end
local function rotate(x, z)
  if math.abs(x - z) == 1 and
     math.abs(x + z) == 1 then
    while turtle.dirX ~= x or
          turtle.dirZ ~= z do
      right()
    end
  end
end
local function init(x, y, z, dirX, dirZ)
  rawset(turtle, "x", x)
  rawset(turtle, "y", y)
  rawset(turtle, "z", z)
  rawset(turtle, "dirX", dirX)
  rawset(turtle, "dirZ", dirZ)
end
local function front()
  x, y, z = turtle.loc()
  dirX, dirZ = turtle.dir()
  return x + dirX, y, z + dirZ
end
rawset(turtle, "select", select)
rawset(turtle, "forward", forward)
rawset(turtle, "back", back)
rawset(turtle, "turnLeft", left)
rawset(turtle, "turnRight", right)
rawset(turtle, "up", up)
rawset(turtle, "down", down)
rawset(turtle, "loc", loc)
rawset(turtle, "dir", dir)
rawset(turtle, "rotate", rotate)
rawset(turtle, "init", init)
rawset(turtle, "front", front)