Tunneler.lua

-- 3x3 Tunnel and Block Placer --
--[[
    This program creates a 3x3 tunnel with
    specifc blocks.
--]]

-- Configuration --
local length = 21 -- Do not set more than 21 blocks

--Fuction Definitions --
local function digCenterLine() --Digs Centerline of Tunnel
    while turtle.detect() do
        turtle.dig()
    end
    turtle.forward()
    while turtle.detectUp() do
        turtle.digUp()
        os.sleep(0.5)
    end
    turtle.digDown()
end

local function turnAround()
    turtle.turnRight()
    turtle.turnRight()
end

local function placeSideBlock(block)
    digCenterLine()
    if not turtle.detectDown() then
        turtle.select(block)
        turtle.placeDown()
    end
    if not turtle.detectUp() then
        turtle.select(block)
        turtle.placeUp()
    end
    turtle.back()
    turtle.select(block)
    turtle.place()
end

local function placeBottomBlock()
    if turtle.detectDown() then
        turtle.digDown()
        os.sleep(0.5)
    end
    turtle.select(3)
    turtle.placeDown()
end

local function placeTopBlock()
    if turtle.detectUp() then
        turtle.digUp()
        os.sleep(0.5)
    end
    turtle.select(4)
    turtle.placeUp()
end

local function digTunnel()
    digCenterLine()
    turtle.turnLeft()
    digCenterLine()
    placeSideBlock(1)
    turnAround()
    turtle.forward()
    digCenterLine()
    placeSideBlock(2)
    turnAround()
    turtle.down()
    placeBottomBlock()
    turtle.forward()
    placeBottomBlock()
    turtle.forward()
    placeBottomBlock()
    turnAround()
    turtle.up()
    turtle.up()
    placeTopBlock()
    turtle.forward()
    placeTopBlock()
    turtle.forward()
    placeTopBlock()
    turnAround()
    turtle.forward()
    turtle.down()
    turtle.turnRight()
end

-- Program --
turtle.up()
for i=0, length - 1 do
    digTunnel()
    if i % 7 == 0 then
        turtle.up()
        turtle.digUp()
        turtle.select(5)
        turtle.placeUp()
        turtle.down()
    end
end
turtle.down()