(let [
    robot (require "robot")
    shell (require "shell")

    (args opts) (shell.parse ...)
    depth (tonumber (. args 1))
    
    swingV (if opts.up robot.swingUp robot.swingDown)
    placeV (if opts.up robot.placegDown robot.placeeUp)
    detectV (if opts.up robot.detectUp robot.detectDown)
    moveV (if opts.up robot.up robot.down)
    run (fn [cmd]
        (let [(ok err) (cmd)]
            (assert ok (.. "Failed to run command: " err))))]


    (if (~= (# args) 1)
        (error "Usaage: place-shaft <depth>"))

    (assert (> depth (robot.count 1)) "Not enough materials to place.")
    (robot.select 1)

    (for [i 1 (- depth 1)]
        (let [ok what (detectV)]
            (if (or (= what "block") (= what "solid"))
                (run swingV)
                ((and (not ok) (~= what "air")))
                (error (.. "Can not pass through: " what))))
        (run moveV)
        (run placeV)
    )

    (run robot.back)
    (run robot.place)
    nil)