motion

x,y,z,dir=0,0,0,0
fuelSlot=1
function refuel()
  turtle.select(fuelSlot)
  turtle.refuel(1)
end
function forward()
  reussit=turtle.forward()
  if not reussit then
    if turtle.getFuelLevel()==0 then
      refuel()
    else
      turtle.dig()
    end
    reussit=turtle.forward()
  end
  if reussit then
    if dir==0 then
      x=x+1
    elseif dir==1 then
      y=y+1
    elseif dir==2 then
      x=x-1
    elseif dir==3 then
      y=y-1
    end
  end
  return reussit
end
function back()
  reussit=turtle.back()
  if not reussit then
    if turtle.getFuelLevel()==0 then
      refuel()
    end
    reussit=turtle.back()
  end
  if reussit then
    if dir==0 then
      x=x-1
    elseif dir==1 then
      y=y-1
    elseif dir==2 then
      x=x+1
    elseif dir==3 then
      y=y+1
    end
  end
  return reussit
end
function up()
  reussit=turtle.up()
  if not reussit then
    if turtle.getFuelLevel()==0 then
      refuel()
    else
      turtle.digUp()
    end
    reussit=turtle.up()
  end
  if reussit then
    z=z+1
  end
  return reussit
end
function down()
  reussit=turtle.down()
  if not reussit then
    if turtle.getFuelLevel()==0 then
      refuel()
    else
      turtle.digDown()
    end
    reussit=turtle.down()
  end
  if reussit then
    z=z-1
  end
  return reussit
end
function turnRight()
  turtle.turnRight()
  dir=(dir+1)%4
end
function turnLeft()
  turtle.turnLeft()
  dir=dir-1
  if dir==-1 then
    dir=0
  end
end
function setDir(d)
  dif=dir-d
  if math.abs(dif)>2 then
    if dif>0 then
      dif=4+dif
    else
      dif=dif-4
    end
  end
  while dir~=d do
    if dif>0 then
      turnLeft()
    else
      turnRight()
    end
  end
end
function reset()
  x,y,z,dir=0,0,0,0
end
function setFuelSlot(s)
  fuelSlot=s
end