computercraft turtle position tracker

pos.lua

local V = vector.new
local R = function(v, r)
    local f = r > 1 and -1 or 1
    if r % 2 == 1 then
        return V(-v.z * f, v.y, v.x * f)
    end
    return V(v.x * f, v.y, v.z * f)
end
 
 
moveUpdates = {
    forward = {1, 0, 0, 0},
    back = {-1, 0, 0, 0},
    turnLeft = {0, 0, 0, -1},
    turnRight = {0, 0, 0, 1},
    up = {0, 1, 0, 0},
    down = {0, -1, 0, 0}
}
 
function savePos()
    local h = fs.open("/.pos", "w")
    h.write(textutils.serialize(turtle.pos))
    h.close()
    --print(unpack(turtle.pos))
end
 
function loadPos()
    local h = fs.open("/.pos", "r")
    if h ~= nil then
        turtle.pos = textutils.unserialize(h.readAll())
        h.close()
        term.setTextColor(0x100)
        term.write("current position is: ")
        term.setTextColor(0x2000)
        print(turtle.pos[1], turtle.pos[2], turtle.pos[3], string.sub("ESWN", turtle.pos[4] + 1, turtle.pos[4] + 1))
        term.setTextColor(0x100)
        print("if incorrect, 'rm /.pos' and reboot")
        term.setTextColor(1)
    else
        local p = {}
        term.setTextColor(0x2000)
        print("Please enter turtle coordinates")
        term.setTextColor(1)
        term.write("x: ")
        p[1] = tonumber(read())
        assert(p[1] ~= nil)
        term.write("y: ")
        p[2] = tonumber(read())
        assert(p[2] ~= nil)
        term.write("z: ")
        p[3] = tonumber(read())
        assert(p[3] ~= nil)
        term.write("orientation (N/E/S/W): ")
        local ori = string.upper(read())
        if ori == "E" then
            p[4] = 0
        elseif ori == "S" then
            p[4] = 1
        elseif ori == "W" then
            p[4] = 2
        elseif ori == "N" then
            p[4] = 3
        end
        assert(p[4] ~= nil)
        turtle.pos  = p
        savePos()
    end
end
 
 
term.clear()
term.setCursorPos(1, 1)
loadPos()
 
for k, move in pairs(moveUpdates) do
    local fn = turtle[k]
    turtle[k] = function()
        local oldPos = turtle.pos
        local posV = V(unpack(oldPos)) + R(V(unpack(move)), oldPos[4])
        turtle.pos = { posV.x, posV.y, posV.z, (oldPos[4] + 4 + move[4]) % 4 }
        savePos()
        local r = fn()
        if not r then
            turtle.pos = oldPos
            savePos()
        end
        return r
    end
end

Keeps track of the turtles location by proxying the turtle.forward, etc api functions. just run it at startup (add shell.run("pos.lua") to startup.lua), no additional modification of other programs is needed to make use of it.
Current position can be read out from the turtle.pos object.

https://pastebin.com/z4QEQiQ0

In the process I also made a simple move from keystroke script: https://pastebin.com/C9czv3Zr