ComputerCraft bridge Program [wip] v1.0

-- get arguments into the array
local tArgs = { ... }

if #tArgs < 1 or #tArgs > 2 then
    term.clear()
    term.setCursorPos(1,1)
    print ( "Incorrect arguments!" )
    print ( "--------------------")
    print ( "Syntax: bridge <length> <width>" )
    print ( "Both values are mandatory." )
    print ( "" )
    print ( "Type \"bridge ?\" or \"bridge help\" for more information." )
    return
elseif (#tArgs < 2) and (tArgs[1] == '?' or tArgs[1] == 'help' or tArgs[1] == 'halp') then
    term.clear()
    term.setCursorPos(1,1)
    print ( "Syntax: bridge <length> <width>" );
    print ( "" )
    print ( "Example:" )
    print ( "--------" )
    print ( "\"bridge 20 15\"" )
    print ( "" )
    print ( "Creates a 20 long, 15 wide platform." )
    print ( "Both values are mandatory." )
    return
end

-- define length and width based on arguments
local length = tonumber( tArgs[1] )
local width = tonumber( tArgs[2] )

-- helper variables
local slot = 1
local row = 1


-- functions
--------------

local function placeBlock()
    while not turtle.placeDown() do
        -- if turtle can't place block check if it can dig down
        if not turtle.digDown() then

            -- if turtle can't dig down check other slots for building materials
            slot = slot + 1
            -- if it reaches slot 16 and not building materials are found
            -- stop and wait for player to refill it
            if slot > 16 then
                slot = 1
                term.clear()
                term.setCursorPos(1,1)
                print ("WARNING: No Blocks in my inventory.")
                print ("Please provide more materials to build.")
                print("")
                print (" - Press <Enter> to continue operation")
                print (" - Hold Ctrl + T to cancel operation.")
                input = read("*")
            end
            turtle.select(slot)
        end
    end
end

local function moveForward()
    while not turtle.forward() do
        -- if turtle can't move forward, check fuel levels
        fuel = turtle.getFuelLevel()
        -- if no fuel
        if fuel < 1 then
            -- stop and wait for fuel
            while not turtle.refuel() do
                term.clear()
                term.setCursorPos(1,1)
                print("WARNING: Fuel level is ".. fuel)
                print("Waiting for fuel...")
            end
        end
    end
end

local function makeTurn()

            turtle.forward()
        if row % 2 == 0 then
            -- if even number turn left
            turtle.turnLeft()
            turtle.forward()
            turtle.turnLeft()
        else
            -- if not even, turn left
            turtle.turnRight()
            turtle.forward()
            turtle.turnRight()
        end
        turtle.forward()
        row = row + 1

end


-- the job
------------

turtle.select(slot)
turtle.forward()

for j = 1, width do
    for i= 1, length do
        placeBlock()
        if i~= length then
            moveForward()
        end
    end
    if j ~= width then
        makeTurn()
    end
end