Turtle Postman

args = {...}

local home = vector.new(0,0,0)
local target = vector.new(0,0,0)
local actualP = vector.new(0,0,0)
local orientation = {h=0,t=0,a=0}
local orientations = {"north", "east", "south", "west"}
local zDiff = {-1, 0, 1, 0}
local xDiff = {0, 1, 0, -1}

local function addposition(name,x,z,y,f)
local fLocation = fs.open(name,"w")
        fLocation.writeLine(x)
        fLocation.writeLine(y)
        fLocation.writeLine(z)
        fLocation.writeLine(f)
fLocation.close()
end

local function getposition(name)
        local fLocation = fs.open(name,"r")
        if name=="home" then
        home = vector.new(tonumber(fLocation.readLine()),tonumber(fLocation.readLine()),tonumber(fLocation.readLine()))
        orientation.h = tonumber(fLocation.readLine())
        orientation.a = orientation.h
        else
        target = vector.new(tonumber(fLocation.readLine()),tonumber(fLocation.readLine()),tonumber(fLocation.readLine()))
        orientation.t = tonumber(fLocation.readLine())
        end
        fLocation.close()
end

function left()
    orientation.a = orientation.a - 1
    orientation.a = (orientation.a - 1) % 4
    orientation.a = orientation.a + 1
    turtle.turnLeft()
end

function right()
    orientation.a = orientation.a - 1
    orientation.a = (orientation.a + 1) % 4
    orientation.a = orientation.a + 1
    turtle.turnRight()
end

function moveForward()
    actualP.x = actualP.x + xDiff[orientation.a]
    actualP.z = actualP.z + zDiff[orientation.a]
        moved = false
    while not(moved) do
    while turtle.detect() do
    turtle.dig()
    end
        moved = turtle.forward()
    end
end

function moveUp()
    actualP.y = actualP.y + 1
    turtle.digUp()
    moved = false
    while not(moved) do
    while turtle.detectUp() do
       turtle.digUp()
      end
        moved = turtle.up()
    end
end

function moveDown()
    actualP.y = actualP.y - 1
    turtle.digDown()
    moved = false
    while not(moved) do
        moved = turtle.down()
    end
end

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

function goto(xTarget, zTarget, yTarget)
    while yTarget < actualP.y do
        moveDown()
    end

    while yTarget > actualP.y do
        moveUp()
    end

    if xTarget < actualP.x then
        look("west")
        while xTarget < actualP.x do
            moveForward()
        end
    end

    if xTarget > actualP.x then
        look("east")
        while xTarget > actualP.x do
            moveForward()
        end
    end

    if zTarget < actualP.z then
        look("north")
        while zTarget < actualP.z do
            moveForward()
        end
    end

    if zTarget > actualP.z then
        look("south")
        while zTarget > actualP.z do
            moveForward()
        end
    end
end

function deliver()
    look(orientations[orientation.t])
    for i = 1,16 do
        turtle.select(i)
        turtle.drop()
    end
    turtle.select(1)

    goto(home.x,home.z,home.y)
    look(orientations[orientation.h])
end

function checkargs()
if #args == 1 and fs.exists(args[1])then
return true
elseif #args == 1 and not fs.exists(args[1])then
print("Unknown Location")
return false
elseif #args > 1 and #args < 6 then
print("not enough parameters")
return false
elseif not tonumber(args[3]) or not tonumber(args[4]) or not tonumber(args[5]) or not tonumber(args[6]) then
print("Arguments 3 to 6 need to be numeric")
return false
else
return true
end
end

print("use <mail> add <name> x z y f to add a position")
print(" f = facing get it by pressing f3 ")
print("use mail <name> to send the turtle to a place you added before")

checkargs()
if checkargs() == true then
if tostring(args[1]) == "add" then
 if fs.exists(args[2]) then
    print("Name already Exists")
  else
   addposition(args[2],args[3],args[4],args[5],args[6])
   print("eingetragen")
 end
end

if #args == 1 then
if fs.exists("home") then
getposition("home")
getposition(tostring(args[1]))
actualP = vector.new(home.x,home.y,home.z)
goto(target.x,target.z,target.y)
deliver()
else
print("Set homeposition first")
end
end
end