Re: How can I have multiple scripts running simultaneously and have scripts pause and wait? (eg. using Lua for a MUD)

["John Klimek" <jklimek@...>]

Thanks for the excellent reply!

I've posted a message on your forum with more questions...

However, it sounds like I should just use one lua_state but
yield/resume different coroutines based on whether or not they are
waiting for input or an event...


On 8/8/07, Nick Gammon <nick@gammon.com.au> wrote:
>
> On 09/08/2007, at 4:59 AM, John Klimek wrote:
>
> > We will have lots scripts running and I'm not sure how to handle a
> > few issues:
> >
> > 1) Should I just have one lua_state or one lua_state for each user?
> > 2) Suppose I want to ask the user a question and get a response in
> > a Lua script?
>
> You are asking about the server end, right?
>
> I have done a considerable amount of work on this very question, as I
> started writing a MUD in straight Lua, and am collaborating with
> David Haley on doing a MUD server written in C++ with Lua scripting.
>
> I have also added Lua scripting into an existing SMAUG MUD code-base,
> see this forum posting for the exact details:
>
> http://www.gammon.com.au/forum/?id=8000
>
>
> In the MUD written entire in Lua, I used a single Lua state for the
> whole MUD, as players needed to communicate with each other.
>
> For the Lua add-on to SMAUG, I initially made a state per player,
> because each state was only concerned with things that player was
> doing (eg. their own quests). Then I added another per-MUD state to
> handle things (like resetting an area) that was not directly related
> to any particular player.
>
> This post describes the scripted reset system:
>
> http://www.gammon.com.au/forum/?id=8027
>
>
> To make scripts pause and wait I would definitely use coroutines,
> they are ideal for that purpose. In your example of asking the player
> a question, you display the question, and yield the coroutine in such
> a way that the server knows that you are awaiting player input. Then
> when the player input arrives (or, a timeout occurs), the coroutine
> is resumed.
>
> I did an example of doing that at the MUD client end, here:
>
> http://www.gammon.com.au/forum/?id=4956
>
> The above example uses a combination of Lua scripting, and timers and
> triggers implemented in C++ code in the client.
>
> An example of using coroutines in the Lua MUD is this:
>
>     Send (client, "What would you like to be called? ...")
>     name = coroutine.yield ()
>
> In this example the player input is returned from the yield, so your
> script can just be written using natural loops, as if the player had
> control over the entire server.
>
> You are welcome to take this discussion to my forum, which maintains
> an active interest in both Lua and MUDs.
>
>
> - Nick Gammon
>
>