LUA Hello World

shell.run('clear')
args = {...}

local length = tonumber(args[1])
local width = tonumber(args[2])

local dirIsForward = true
for i = 0, width-1, 1 do
    for j = 0, length-1, 1 do
        while turtle.detect() do
            turtle.dig()
        end
        turtle.forward()
        local yCount = 0
        while(turtle.detectUp()) do
            turtle.digUp()
            turtle.up()
            yCount = yCount + 1
        end
        while (yCount ~= 0) do
            turtle.down()
            yCount = yCount - 1
        end
    end
    if dirIsForward and j ~= width-1 then
        turtle.turnRight()
        while turtle.detect() do
            turtle.dig()
        end
        turtle.forward()
        turtle.turnRight()
    elseif not dirIsForward and j ~= width-1 then
        turtle.turnLeft()
        while turtle.detect() do
            turtle.dig()
        end
        turtle.forward()
        turtle.turnLeft()
    end
    dirIsForward = not dirIsForward
end