piston-pusher.lua

function iterate()
    local timer = os.startTimer(5)
    local event = os.pullEvent()

    if event ~= "redstone" and event ~= "timer" then
        return
    end

    if event == "redstone" then
        if not redstone.getInput("bottom") and not redstone.getInput("left") then
            return
        end
    end

    os.cancelTimer(timer)
    print("[cr] caught event")
    sleep(0.1)

    print("[cr] pushing piston")
    redstone.setOutput("right", true)
    sleep(0.1)

    print("[cr] retracting piston")
    redstone.setOutput("right", false)
    sleep(0.3)
end

function main()
    print("\n\n-------------------------------")
    print("[cr] starting the program; v1.0")
    print("-------------------------------\n\n");

    while true do
        iterate()
    end
end

main()