Shear Sheep Auto Home 3x3

xCurrent = 0
zCurrent = 0
yCurrent = 0

xHome = 0
zHome = 0
yHome = 0

orientation = 4
orientations = {"north", "east", "south", "west"}

startDirection = orientation

zDiff = {-1, 0, 1, 0}
xDiff = {0, 1, 0 ,-1}

function upMove()
    yCurrent = yCurrent + 1
    turtle.up()
end

function downMove()
    yCurrent = yCurrent - 1
    turtle.down()
end

function forwardMove()
    xCurrent = xCurrent + xDiff[orientation]
    zCurrent = zCurrent + zDiff[orientation]

    turtle.forward()
end

function backMove()
    xCurrent = xCurrent - xDiff[orientation]
    zCurrent = zCurrent - zDiff[orientation]

    turtle.back()
end

function leftMove()
    orientation = orientation - 1
    orientation = (orientation - 1) % 4
    orientation = orientation + 1

    turtle.turnLeft()
    forwardMove()
end

function rightMove()
    orientation = orientation - 1
    orientation = (orientation + 1) % 4
    orientation = orientation + 1

    turtle.turnRight()
    forwardMove()
end

function left()
    orientation = orientation - 1
    orientation = (orientation - 1) % 4
    orientation = orientation + 1

    turtle.turnLeft()
end

function right()
    orientation = orientation - 1
    orientation = (orientation + 1) % 4
    orientation = orientation + 1

    turtle.turnRight()
end

function look(direction)
    while direction ~= orientations[orientation] do
      right()
    end
end

function goto(xHome, zHome, yHome)

    while yHome < yCurrent do
        downMove()
    end
    while yHome > yCurrent do
        upMove()
    end
    if xHome < xCurrent then
      look("west")
      while xHome < xCurrent do
        forwardMove()
      end
    end
    if xHome > xCurrent then
      look("east")
      while xHome > xCurrent do
        forwardMove()
      end
    end
    if zHome < zCurrent then
      look("north")
      while zHome < zCurrent do
        forwardMove()
      end
    end
    if zHome > zCurrent then
      look("south")
      while zHome > zCurrent do
        forwardMove()
      end
    end
    while not(orientation == startDirection) do
        right()
    end
end

function shearDown()
    while not(turtle.placeDown()) do
        turtle.placeDown()
        turtle.suckUp()
    end
end

function dropOff()
    turtle.select(2)
    while turtle.getItemCount() > 0 do
        turtle.drop()
    end
    turtle.select(1)
end

function forwardShear()
    forwardMove()
    shearDown()
end

function leftShear()
    leftMove()
    shearDown()
end

function rightShear()
    rightMove()
    shearDown()
end

function startDrop()
    backMove()
    left()
    dropOff()
end

function backToStart()
    leftMove()
    leftMove()
    forwardMove()
    left()
end

function shearCheck()
    turtle.select(1)
    if turtle.getItemCount() == 0 then
        goto(0, 0, 0)
    end
end

function shearThree()
    shearDown()
    shearCheck()
    forwardShear()
    shearCheck()
    forwardShear()
    shearCheck()
    leftMove()
    shearCheck()
    left()
    shearCheck()
    forwardShear()
    shearCheck()
    forwardShear()
    shearCheck()
    rightMove()
    shearCheck()
    right()
    shearCheck()
    forwardShear()
    shearCheck()
    forwardShear()
    shearCheck()
    startDrop()
    shearCheck()
    backToStart()
    shearCheck()
end

while true do
    shearThree()
    sleep(2)
end