platform builder with cmd line arg

local turnLeft=true;
local failCount=0;
local breakFloor=true;
local sel=0;
local slot=1
local width=1;
local length=1;
local args={...}
print("ceiling builder by Niseg")
print("refuel the turtle put tell it to go down 2 and start")
turtle.select(slot)
if #args==3 then
    width=tonumber(args[1])
    length=tonumber(args[2])
    sel=tonumber(args[3])
    if width<1 or length <1 then
    print("invalid length or width")
    exit()
    end
--  print("args3="+args[3])
    if sel ~=1 and sel~=2 then
        print("3rd arg invalid 1 right 2 left")
        exit(1)
    end

else

    repeat
    print("width ")

    width=tonumber(read())
    until width>0


    repeat
    print("length ")

    length=tonumber(read())
    until length>0


    repeat
    print("build to  (1) right ")
    print("built to  (2) left")

    sel=tonumber(read())
    until sel==1 or sel==2
end
if(sel==1) then turnLeft=false end

for i= 1,width,1 do
        for j= 1,length,1 do
        if turtle.getItemCount(slot)==0 then
                slot=slot+1
                if slot <17 then
                        turtle.select(slot)
                end
        end
        turtle.placeUp()
        if j <length then turtle.forward() end

end
                if(turnLeft) then turtle.turnLeft()  else turtle.turnRight() end
                turtle.forward()
                if(turnLeft) then turtle.turnLeft()  else turtle.turnRight() end
                turnLeft = not turnLeft;

        end
print("done")