Pumpkin Farmer V0.1

--Pumpkin Farmer V0.1 by QQII
--Declerations
local length = 0
local width = -1

--Functions
local function refuel()
    while turtle.getFuelLevel() <= 0 do
        shell.run("refuel", "all")
        if turtle.getFuelLevel() <= 0 then
            print("ERROR: out of fuel")
            read()
        end
    end
end

local function forward()                --Moves forward
    refuel()
    while not turtle.forward() do
        while not turtle.dig() do
            turtle.attack()
        end
    end
end

local function digDown()                --Digs down
    if turtle.detectDown() then
        while not turtle.digDown() do
            turtle.attackDown()
        end
    end
end

local function line(l)                  --Harvests a line of l
    for i = 1, l do
        forward()
        digDown()
    end
    forward()
end

local function clearSlot(slotNumber)            --Attemps to clear the slot slotNumber
    if turtle.getItemCount(slotNumber) ~= 0 then
        turtle.select(slotNumber)
        if not turtle.drop() then
            print("ERROR: failure to clear slot number " .. slotNumber)
        end
    end
end

local function clearSlots()             --Places all the items into the chest infront of the turtle
    for i = 1,16 do
        if turtle.getItemCount(i) ~= 0 then
            clearSlot(i)
        end
    end
end

--User Inputs
print("The turtle will harvest a a pumpkin or melon farm")
if length < 1 then
    io.write("Length: ")
        while length <= 0 do
            length = tonumber(read())
        end
end
if width < 0 then
    io.write("Width: ")
        while width <= 0 do
            width = tonumber(read())
        end
end

--Main Script
refuel()
while true do
    clearSlots()
    os.sleep(length * 30)
    for i = 1, 2 do
        turtle.turnRight()
        line(width)
        turtle.turnRight()
        line(length)
    end
end