ironblocks.lua

local craftSlots = {1, 2, 3, 5, 6, 7, 9, 10, 11}
local nonCraftSlots = {4, 8, 12, 13, 14, 15, 16}

while true do
    failed = false
    for _, i in ipairs(craftSlots) do
        if turtle.getItemCount(i) < 64 then
            turtle.select(i)
            turtle.suckDown(64-turtle.getItemCount())
        end
        if turtle.getItemCount(i) == 0 then
            failed = true
        end
    end
    for _, i in ipairs(nonCraftSlots) do
        if turtle.getItemCount(i) > 0 then
            turtle.dropDown()
        end
    end
    if not failed then
        turtle.craft()
        for i=1, 16 do
            detail = turtle.getItemDetail(i)
            if detail and detail.name == "minecraft:iron_block" then
                turtle.select(i)
                turtle.drop()
            end
        end
    elseif failed then
        sleep(5)
    end
end