ComputerCraft Bridger

local function GetItemCount()
    local ItemCount = 0;

    for i = 1, math.huge do
        local Success, Result = pcall(function()
            return turtle.getItemCount(i)
        end)
        ItemCount = ItemCount + (Success and Result or 0)
        if not Success then
            break;
        end
    end

    return ItemCount;
end

local function left(times)
    times = times or 1
    for _ = 1, times do
        turtle.turnLeft()
    end
end

local function right(times)
    times = times or 1
    for _ = 1, times do
        turtle.turnRight()
    end
end

local Blocks = GetItemCount();

local Settings = {
    LavaCheck = false
}

local Output = string.format("Placing %d blocks, Approximate time: ~%.2f seconds", Blocks, Blocks * .85)
print(Output)

local function Bridge()
    local function GetMostOwnedItem()
        local Items, Slot = 0, 0;

        for i = 1, math.huge do
            local Success, Result = pcall(function()
                return turtle.getItemCount(i)
            end)
            if not Success then
                break;
            end

            if Result > Items then
                Items = Result
                Slot = i
            end
        end

        return Slot;
    end

    local function Place()
        if not turtle.detectDown() then
            if turtle.getItemCount(turtle.getSelectedSlot()) == 0 and #GetItemCount() > 0 then
                turtle.select(GetMostOwnedItem())
            end
            turtle.placeDown()
        end
    end

    local function MoveAndPlace(Steps)
        Steps = Steps or 1;

        for _ = 1, Steps do
            turtle.forward()
            Place()
        end
    end

    local function IsLava()
        local _, Data = turtle.inspect()

        return Data.name == "minecraft:lava"
    end

    local function Main()
        MoveAndPlace()
        if turtle.detect() then
            turtle.dig()
        end
        if turtle.detectUp() then
            turtle.digUp()
        end
        -- Check it's sides to see if there is any lava
        if Settings.LavaCheck then
            right()
            if IsLava() then
                turtle.place()
            end
            left(2)
            if IsLava() then
                turtle.place()
            end
            right()
        end
    end

    -- Keep building until the turtle runs out of items
    while GetItemCount() ~= 0 do
        Main()
    end
end

print("Do you wanna check for lava? (Y/N)")

Settings.LavaCheck = string.lower(read()) == "y" and true or false

print("LavaCheck:",Settings.LavaCheck)

Bridge()

print("Finished making bridge!")