Internal tracking system for computercraft turtles BETA | test branch

local xPos, yPos, zPos = nil
face = nil
cal = false

function setLocation() -- get gps using other computers
 xPos, yPos, zPos = gps.locate()
 if turtle.forward() then
 nxPos, nyPos, nzPos = gps.locate()
 end
 turtle.back()
 if zPos > nzPos then --if north
    face = 0
 end
 if xPos < nxPos then --if east
    face = 3
 end
 if zPos < nzPos then --if south
    face = 2
 end
 if xPos > nxPos then --if west
    face = 1
 end
 cal = true
end

function manSetLocation(x, y, z, f) -- manually set location
 xPos = x
 yPos = y
 zPos = z
 face = f
 cal = true
end

function getLocation() -- return the location
 if xPos ~= nil then
  return xPos, yPos, zPos, face
 else
  return nil
 end
end

function turnLeft() -- turn left
if turtle.turnLeft() then
 if face == 0 then
  face = 1
    elseif face == 1 then
    face = 2
    elseif face == 2 then
    face = 3
    elseif face == 3 then
    face = 0
  end
end
end

function turnRight() -- turn right
if turtle.turnRight() then
 if face == 0 then
  face = 3
    elseif face == 1 then
    face = 0
    elseif face == 2 then
    face = 1
    elseif face == 3 then
    face = 2
 end
end
end

function forward() -- go forward
 if turtle.forward() then
   if cal == true then
   if face == 0 then
      zPos = zPos - 1
    elseif face == 1 then
      xPos = xPos - 1
    elseif face == 2 then
      zPos = zPos + 1
    elseif face == 3 then
      xPos = xPos + 1
   end
   else
      print("Not Calibrated.")
   end
   end
 end

function back() -- go back
 if turtle.back() then
   if cal == true then
   if face == 0 then
      zPos = zPos + 1
   elseif face == 1 then
      xPos = xPos + 1
   elseif face == 2 then
      zPos = zPos - 1
   elseif face == 2 then
      xPos = xPos - 1
   end
   else
      print("Not Calibrated.")
   end
   end
end
function up() -- go up
 turtle.up()
 if cal == true then
  yPos = yPos + 1
 else
  print("Not Calibrated.")
 end
end

function down() -- go down
 turtle.down()
 if cal == true then
  yPos = yPos - 1
 else
  print("Not Calibrated.")
 end
end

function saveData(l)
   if not fs.isDir(l) then
      local f = fs.open(l,"a")
      if cal ~= false then
            f.writeLine("Current location: "..xPos..", "..yPos..", "..zPos..", Face:"..face)
      else
         if gps.locate() then
            x,y,z = gps.locate()
            f.writeLine("Current location: "..x..", "..y..", "..z..", Face: N/A")
         else
            error("location unknown")
         end
         f.close()

      end
   else
      print("Dir With that name already exists")
   end
end