Computercraft Tree Felling

-- Updated to work with Minecraft 1.6.4
-- Slot 1: Saplings
-- Slot 2: Bonemeal
-- Usage: treeFelling <trees> <chest side>
-- "Trees" is how many saplings to grow and cut down.  This is a numerical value.
-- "Chest side" is the side a chest is to empty inventory into.  "Back", "Left", "Right", and "Bottom" are supported
-- If no arguments are given, one tree will be grown and cut-down with the inventory staying in the turtle.
-- The second argument is optional, but if used the first is required.


local trees = {...}
local progEnd = 0

function goUp()
    while turtle.up() == false do
        turtle.digUp()
        turtle.attackUp()
    end
end

function goDown()
    while turtle.down() == false do
        turtle.digDown()
        turtle.attackDown()
    end
end

function goForward()
    while turtle.forward() == false do
        turtle.dig()
        turtle.attack()
    end
end

function goBack()
    turtle.turnLeft()
    turtle.turnLeft()
    goForward()
    turtle.turnLeft()
    turtle.turnLeft()
end

function plant()
    turtle.select(1)
    if turtle.getItemCount(1) == 0 then
        print("Out of saplings, replace and press any key")
        print("Press 'Q' to quit")
        local event, param1 = os.pullEvent ("char")
        if param1 == "q" then
            progEnd = 1
            return
        end
    end
    turtle.place()
    turtle.select(2)
    if turtle.getItemCount(2) == 0 then
        print("Out of bonemeal, replace and press any key")
        print("Press 'Q' to quit")
        local event, param1 = os.pullEvent ("char")
        if param1 == "q" then
            progEnd = 1
            return
        end
    end
    while turtle.place() == true do
    end
    turtle.select(3)
end

function emptyInventory(dir)
    for i=3,16 do
        turtle.select(i)
        if turtle.compareTo(1) == true then
            turtle.transferTo(1)
        elseif turtle.compareTo(2) == true then
            turtle.transferTo(2)
        end
    end
    if string.lower(dir) == "back" then
        turtle.turnLeft()
        turtle.turnLeft()
        for i=3,16 do
            turtle.select(i)
            turtle.drop()
        end
        turtle.turnLeft()
        turtle.turnLeft()
    elseif string.lower(dir) == "bottom" then
        for i=3,16 do
            turtle.select(i)
            turtle.dropDown()
        end
    elseif string.lower(dir) == "left" then
        turtle.left()
        for i=3,16 do
            turtle.select(i)
            turtle.drop()
        end
        turtle.right()
    elseif string.lower(dir) == "right" then
        turtle.right()
        for i=3,16 do
            turtle.select(i)
            turtle.drop()
        end
        turtle.left()
    end
end


if #trees < 1 then
    trees[1] = 1
elseif #trees >= 1 then
    if not tonumber(trees[1]) then
        local file = shell.getRunningProgram()
        if string.find(file, "/") ~= null then
            file = string.reverse(file)
            file = string.reverse(string.sub(file, 1, string.find(file, "/") - 1))
        end
        print("Usage: " .. file .. " <number> <side>")
        print("Number: amount of trees to be chopped")
        print("Side: Side output chest is on (optional)")
        return
    end
end
for i=1,trees[1] do
    local dist = 0
    plant()
    if progEnd == 1 then
        print("User exit")
        return
    end
    goForward()
    while turtle.detectUp() == true do
        goUp()
        dist = dist + 1
    end
    for o=1,dist do
        goDown()
    end
    goBack()
    if not trees[2] then
        trees[2] = "none"
    end
    emptyInventory(trees[2])
end
print("Program Complete")