View difference between Paste ID: FMx5qRXF and eV1sY0CV

 -- Program for Farming Turtle from ComputerCraft mod.
 -- AutoFarm Ver 1.0
 -- Copyright  (c)  2015  Alexander Andreyev <aravsar@ya.ru>
 --   Farming 9x9 field
 -- I S x x x x x x x x
 --   x x x x x x x x x
 --   x x x x x x x x x
 --   x x x x x x x x x
 --   x x x x W x x x x
 --   x x x x x x x x x
 --   x x x x x x x x x
 --   x x x x x x x x x
 --   x x x x x x x x x
 -- S - start position
 -- I - possible inventory with which interacts turtle in the end (do_end_stuff)
 -- W - water block in center
 -- The turtle moves clockwise from S to W by spiral,
 -- moves back to the S, drop stuff to I and stops.
 -- The turtle must be in one block above the field.
 
 -- MAIN PROGRAM
 args      = {...}
 chest_name_part = 'Chest' -- a part of name of the I chest
 rings     = {5,3}
 fuel_slot = 16
 
 function _refuel(fuel)
   turtle.select(fuel_slot)
   turtle.refuel(fuel)
 end
 
 function process_field(do_stuff, do_end_stuff)
   for i = 1, #rings do
     local n = rings[i]
     for j = 1, 4 do
       if j == 4 then n = n - 1 end
       for k = 1, n-1 do
         do_stuff()
         turtle.forward()
       end
       turtle.turnRight()
     end
     do_stuff()
     turtle.forward()
   end
   -- moving back on start position
   turtle.turnLeft()
   for i = 1, 4 do turtle.forward() end
   turtle.turnLeft()
   for i = 1, 4 do turtle.forward() end
 
   do_end_stuff()
 
   turtle.turnLeft()
   turtle.turnLeft()
 end
 
 -- PLANTING
 plant_slots = {1,2,3,4}
 
 function plant()
   for i = 1, #plant_slots do
     turtle.select(plant_slots[i])
     if turtle.getItemCount(plant_slots[i]) > 0 then
       turtle.placeDown()
       return
     end
   end
 end
 function planting()
   local s,_ = turtle.inspectDown()
   if s == false then
     turtle.digDown()
     plant()
   end
 end
 function on_end_planting()
 end
 
 -- HARVESTING
 harvest_slots = {5,6,7,8}
 wheat = {name = 'minecraft:wheat', metadata = 7} -- growed up wheat
 
 function harvest(object)
   local _,m = turtle.inspectDown()
   if m.name ~= object.name or m.metadata ~= object.metadata then return end
 
   for i = 1, #harvest_slots do
     turtle.select(harvest_slots[i])
     if turtle.getItemSpace(harvest_slots[i]) > 0 then
       turtle.digDown()
       return
     end
   end
 end
 function harvesting()
   harvest(wheat)
 end
 function on_end_harvesting()
   local _,m = turtle.inspect()
   if m.name:find(chest_name_part) == nil then return end
   for i = 1, #harvest_slots do
     turtle.select(harvest_slots[i])
     turtle.drop()
   end
 end
 
 -- HARVEST AND PLANT
 function harvest_and_plant( ... )
   harvesting()
   planting()
 end
 
 -- Controlling program
 if args[1] == 'p' then
   _refuel(2)
   process_field(planting, on_end_planting)
 elseif args[1] == 'h' then
   _refuel(2)
   process_field(harvesting, on_end_harvesting)
 elseif args[1] == 'ph' then
   _refuel(2)
   process_field(harvest_and_plant, on_end_harvesting)
 else
   print('p  - for planting')
   print('h  - for harvest')
   print('ph - for harvest and plant')
 end