A cut down and basic fun example, we do not make many assumptions so you are free to configure and setup your code to your own tastes.

There are only two parts that you must provide for fun to work. The first is a table describing the virtual hardware component setup, eg the resolution of screen and tilemaps and sprite layers to display.

hardware={
    {
        component="screen",
        size={424,240}, -- lowrez with a 1920x1080 aspect
        scale=3, -- draw in a window at 3 times scale
        fps=60, -- 60 fps please
    },
    ...
}

This requests the virtual hardware that will be setup before main is called. system is a global table that will be created according to your requested hardware and can then be referenced when the main function is called.

The second is a main function which will be called as a yield-able co-routine with a table that should be treated as an incoming message. Use the basic skeleton below to receive need.setup/update/draw requests. As you can see it is possible to have multiple needs at once and this call structure allows for a setup, repeat update/draw then cleanup flow of code within this co-routine.

function main(need)
    if not need.setup then need=coroutine.yield() end -- wait for setup request

    -- perform setup

    local done=false while not done do
        need=coroutine.yield()

        if need.update then

            -- perform update

        end

        if need.draw then

            -- perform draw

        end            

        if need.clean then done=true end -- cleanup requested
    end

    -- perform cleanup

end