Turtle Goto

for a,b in pairs(rs.getSides()) do
  if peripheral.getType(b) == 'modem' then
   rednet.open(b)
   break
  end
end

tArgs = {...}

function compass()
    x,y,z = gps.locate()
    while turtle.forward() == false do
        turtle.turnRight()
    end
    x1,y1,z1 = gps.locate()
    direction = {x = x - x1, y = y - y1, z = z - z1}
    for k,v in pairs( direction ) do
        if k == "x" and v == 1 then
            facing = 1 -- west
        elseif k == "x" and v == -1 then
            facing = 3 -- east
        elseif k == "z" and v == 1 then
            facing = 2 -- north
        elseif k == "z" and v == -1 then
            facing = 0 -- south
        end
    end
    turtle.back()
    return facing
end

function goTo()
xL,yL,zL = gps.locate()
print("Starting from: "..xL.." "..yL.." "..zL)
print("Going to: "..tArgs[1].." "..tArgs[2].." "..tArgs[3])
while true do
    xL,yL,zL = gps.locate()
    x = xL - tArgs[1]
    y = yL - tArgs[2]
    z = zL - tArgs[3]
    if y > 0 then
        while tArgs[4] == "dig" and turtle.down() == false do
            turtle.digDown()
        end
    elseif y < 0 then
        while tArgs[4] == "dig" and turtle.up() == false do
            turtle.digUp()
            turtle.up()
        end
    elseif z < 0 then
        currentDir = compass()
        if currentDir ~= 0 then
            turnTo(0)
        end
        while tArgs[4] == "dig" and turtle.forward() == false do
            turtle.dig()
            turtle.forward()
        end
    elseif z > 0 then
        currentDir = compass()
        if currentDir ~= 2 then
            turnTo(2)
        end
        while tArgs[4] == "dig" and turtle.forward() == false do
            turtle.dig()
            turtle.forward()
        end
    elseif x < 0 then
        currentDir = compass()
        if currentDir ~= 3 then
            turnTo(3)
        end
        while tArgs[4] == "dig" and turtle.forward() == false do
            turtle.dig()
            turtle.forward()
        end
    elseif x > 0 then
        currentDir = compass()
        if currentDir ~= 1 then
            turnTo(1)
        end
        while tArgs[4] == "dig" and turtle.forward() == false do
            turtle.dig()
            turtle.forward()
        end
    else
        break
    end
end
end


function turnTo(Int)
    if facing ~= Int then
        local current = facing - Int
        if current < 0 then
            for i = 1, math.abs(current) do
                turtle.turnRight()
            end
        else
            for i = 1,current do
            turtle.turnLeft()
            end
        end
    end
end

if #tArgs < 3 or #tArgs > 4 then
  print ("Usage: "..shell.getRunningProgram().." <x> <y> <z> <'dig' or leave blank>")
else
  goTo()
end