View difference between Paste ID: NnXa5JCD and DzdzNFkU

 --navigation api to keep track of location
 dirTable = {}
 dirTable[0], dirTable[1], dirTable[2], dirTable[3] = 'front', 'right', 'back', 'left'
 pos = {x = 0, y = 0, z = 0, dir = 0}
 
 if not fs.exists('position.txt') then
     local position = fs.open('position.txt', 'w')
     pos.dir = pos.dir % 4
     position.write(textutils.serialise(pos))
     position.close()
 else
     local position = fs.open('position.txt', 'r')
     pos = textutils.unserialise(position.readAll())
     position.close()
 end
 
 function updatePos()
     pos.dir = pos.dir % 4
     local position = fs.open('position.txt', 'w')
     position.write(textutils.serialise(pos))
     position.close()
 end
 
 function returnPos()
     return pos.x, pos.y, pos.z, pos.dir
 end
 
 function calibrate()
     pos.x, pos.y, pos.z, pos.dir = 0, 0, 0, 0
     updatePos()
 end
 
 function direction(isForward)
     local xDir = 0
     local yDir = 0
     pos.dir = pos.dir % 4
     if pos.dir == 0 then
         xDir = 1
         yDir = 0
     elseif pos.dir == 1 then
         xDir = 0
         yDir = 1
     elseif pos.dir == 2 then
         xDir = -1
         yDir = 0
     elseif pos.dir == 3 then
         xDir = 0
         yDir = -1
     end
     if isForward == true then
         pos.x = pos.x + xDir
         pos.y = pos.y + yDir
     else
         pos.x = pos.x - xDir
         pos.y = pos.y - yDir
     end
     updatePos()
 end
 
 function forward(x)
     for i = 1, x do
         while not turtle.forward() do
             turtle.dig()
         end
         direction(true)
     end
     updatePos()
 end
 
 function back(x)
     for i = 1, x do
         repeat until turtle.back()
         direction(false)
     end
     updatePos()
 end
 
 
 function up(x)
     for i = 1, x do
         while not turtle.up() do
             turtle.digUp()
         end
         pos.z = pos.z + 1
     end
     updatePos()
 end
 
 function down(x)
     for i = 1, x do
         while not turtle.down() do
             turtle.digDown()
         end
         pos.z = pos.z - 1
     end
     updatePos()
 end
 
 function turnRight(x)
     for i = 1, x do
         turtle.turnRight()
         pos.dir = pos.dir + 1
     end
     updatePos()
 end
 
 function turnLeft(x)
     for i = 1, x do
         turtle.turnLeft()
         pos.dir = pos.dir + 3
     end
     updatePos()
 end
 
 function turnAround()
     turnLeft(2)
 end
 
 function goDir(dir)
     while pos.dir % 4 ~= dir do
         turnLeft()
     end
     updatePos()
 end