View difference between Paste ID: FYsUL3eW and Jyr9FZ7x

 local tArgs={...}
 local turtleId
 local isWirelessTurtle
 local messageOutputFileName
 
 
 local function printUsage()
   write([[
 Usage:
 farm <length> <width> [timer]
   <length> is the length of each row
 of the field
   <width> is the number of rows
   [timer] is an optional number of
 seconds to wait before repeating.
 -- Press any key to continue --]])
   os.pullEvent("key")
   print([[
 
 Placement
 The turtle should begin above a chest facing towards the first row, and will move right for each subsequent row. The chest should contain the item to be planted. If the plant has seeds different from the harvested items, like wheat, place a 2nd chest above the turtle for the output.
 Note: If area is not already plowed or
 planted it must be a farming turtle.]])
 end
 
 
 if #tArgs<2 then
   printUsage()
   return
 end
 
 local length=tonumber(tArgs[1])
 local width=tonumber(tArgs[2])
 local repeatTime=tonumber(tArgs[3]) or 0
 
 
 isWirelessTurtle = peripheral.isPresent("right")
 if (isWirelessTurtle == true) then
   turtleId = os.getComputerLabel()
   rednet.open("right")
 end
 
 function writeMessage(message)
     print(message)
 
     -- If this turtle has a modem, then write the message to red net
     if (isWirelessTurtle == true) then
       if (turtleId == nil) then
         rednet.broadcast(message)
       else
         -- Broadcast the message (prefixed with the turtle's id)
         rednet.broadcast("[".. turtleId.."] "..message)
       end
     end
 
     if (messageOutputFileName ~= nil) then
       -- Open file, write message and close file (flush doesn't seem to work!)
       local outputFile = io.open(messageOutputFileName, "a")
       outputFile:write(message)
       outputFile:write("\n")
       outputFile:close()
     end
 end
 
 
 local function repeatUntil(func)
   while not func() do sleep(.5) end
 end
 
 local function step()
-  repeatUntil(turtle.forward)
+	if turtle.detect()
 	then turtle.dig()
      end
   turtle.forward()
   --dry soil occassionally untils between dig and plant,
   --so repeat until successful on planting (or out of things to plant)
   local tryCount=0
   repeat
     turtle.digDown()
     tryCount=tryCount+1
   until turtle.placeDown() or turtle.getItemCount(1)==0 or tryCount==3
 end
 
 
 
 local function waitForKey(prompt)
 	writeMessage(prompt)
   os.pullEvent("key")
 end
 
 
 local function harvest()
   --do I have enough fuel?
   local cost=(length+1)*width
   --if odd rows, add return trip
   if width%2==1 then
     cost=cost+length
   end
   while type(turtle.getFuelLevel())=="number" and cost>turtle.getFuelLevel() do
     waitForKey("Insufficient fuel. Place fuel in any slot and press a key to continue...")
 
     for i=2,16 do
       turtle.select(i)
       if turtle.refuel() then
         break
       end
     end
     turtle.select(1)
     term.clear()
   end
   writeMessage("Harvesting...")
 
   step()
   local turnNext=turtle.turnRight
   local turnOther=turtle.turnLeft
   for row=1,width do
     for pos=1,length-1 do
       step()
     end
     if row<width then
       turnNext()
       step()
       turnNext()
     end
     local temp=turnNext
     turnNext=turnOther
     turnOther=temp
   end
 
   --return to start position
   --if odd number of rows, we're at far end of rows, return
   if width%2==1 then
     for i=1,length do
       --if we hit something, just wait a bit and retry;
       repeatUntil(turtle.back)
     end
     turtle.turnLeft()
   else
     --was even rows, so at right end of rows facing opposite way
     repeatUntil(turtle.forward)
     turtle.turnRight()
   end
   --head back to first row
   for i=1,width-1 do
     repeatUntil(turtle.forward)
   end
   --turn to face starting direction
   turtle.turnRight()
 
   --unload!
   writeMessage("Unloading...")
   --anythign matching what's in slot 1 goes down, rest goes up
   for i=2,16 do
     turtle.select(i)
     if turtle.getItemCount(i)>0 then
       if turtle.compareTo(1) then
         while not turtle.dropDown() do
           waitForKey("input chest full, empty it and press any key to continue...")
 	writeMessage("input chest full, empty it and press any key to continue...")
         end
       else
         while not turtle.dropUp() do
           waitForKey("output chest full, empty it and press any key to continue...")
 	writeMessage("output chest full, empty it and press any key to continue...")
         end
       end
     end
   end
   turtle.select(1)
 end
 
 --load up with stuffs
 turtle.select(1)
 turtle.suckDown()
 
 if repeatTime>0 then
   while true do
     harvest()
     term.clear()
     local i=repeatTime
     while i>0 do
       local tick,interval=1,"second"
       if i>3600 then
         tick,interval=3600,"hour"
       elseif i>60 then
         tick,interval=60,"minute"
       end
       local count=math.floor(i/tick)
       if count==1 and tick>1 then
         tick=i-tick
       else
         interval=interval.."s"
       end
       term.setCursorPos(1,1)
       term.clearLine()
       write("Harvesting again in "..count.." "..interval)
       sleep(tick)
       i=i-tick
     end
   end
 else
   harvest()
   --drop seeds back
   turtle.select(1)
   turtle.dropDown()
 end