Mining Down snippet

while digDown do
    local block, what = robot.detectDown()
    print(what)
    if what == "solid" then
      if robot.swingDown() then
        robot.down()
        depth = depth + 1
      else
        digDown = false
      end
    elseif (what == "replaceable") or (what == "liquid") then
      print("I think there's lava!")
      os.sleep(1)
      local drain = robot.compareFluidDown()
      print(drain)
      while drain do
        os.sleep(2)
        robot.drainDown()
        local detect, thing = robot.detectDown()
        if (thing == "air") then
          drain = false
          print("I did it!")
        else
          print("Nope, no lava this time.")
        end
      end
        robot.down()
        depth = depth + 1
    else
      robot.down()
      depth = depth + 1
    end
  end