Re: Best way to pause (sleep?) inside of lua script

[Pavel Antokolsky aka Zigmar <zigmar@...>]

On 12/12/05, John Klimek <jklimek@gmail.com> wrote:
> Ok, I understand that I have to store this function in the Lua
> registry, but how would I do this from my C/Delphi function?  Can you
> give me a code example?
See the attachment. I've created a simple app (with C++) that allows
to register some hypothetic event handler and later calls to
registered function.

> Also, lets say I have the following code:
>
> -- Funcion to be executed later
> function SayHello()
>   myNewNpc:SayRoom("Hello everybody!");
> end
>
> -- Create a new NPC and store it in "myNewNpc"
> myNewNpc := NPCManager.New("Bob");
>
> -- Create a timer to run the SayHello function in 10 seconds
> local eventId = mud:onTimer(10, SayHello);
>
> -- end of lua script
>
>
> What would the code look like (in C/Delphi) for the onTimer function?
> Also, if I store my function SayHello in the Lua registry and execute
> it later, won't it lose the value of myNewNpc and then throw an error?
>  Would I have to modify my function to something like this:
No, you don't have to. A global variable are always visible and
persistent - once you have declared it - it there until you remove it,
even if the script body finished running. Actually lua-based ini files
parsers - work line this - some variable are declared in script and
host app exectues the script body, and read the global variables
afterwards.
Note the 'a' gloval variable in attached example.

> function SayHello()
>   myNewNpc = NPCManager.GetNPC("Bob");
>   myNewNpc:SayRoom("Hello everybody!");
> end
Here you actually modify (or create) _global_ variable "myNewNpc". If
you wanted to create local variable, you should have written:

function SayHello()
   local myNewNpc = NPCManager.GetNPC("Bob");
   myNewNpc:SayRoom("Hello everybody!");
end


> On 12/11/05, Pavel Antokolsky aka Zigmar <zigmar@gmail.com> wrote:
> > On 12/10/05, John Klimek <jklimek@gmail.com> wrote:
> >
> >  > Zigmar, can you explain what you mean when you say "register a
> >  > function itself, not its name"?
> >  Functions are first-class objects in lua, and therefore function can
> > get another function as parameter, functions can be stored in
> > variables, etc. So what I mean, as the function that registers event,
> > can receive not the name of the function (which therefor must be
> > global) but a function object itself. It allows you to pass local
> > function, function stored in some tables or even anonymous function
> > (as I wrote in example)
> >
> >  > For example, in your lua code you have:
> >  > mud.onTimer(10, function() npc:say("Hello") end )
> >  >
> >  > It looks like mud is a table filled with cfunctions.  Am I right?
> >  Yep. It probably some library filled with function that gives you a
> > connectivity to your host application (mud server). For example
> > queries about different statuses, registering/removing events,
> > spawning monsters, etc.
> >
> >  > Furthermore it looks like you are calling this cfuntion (wherever
> >  > mud.onTimer is mapped) and passing it a lua function parameter.  Am I
> >  > right on this as well?
> >  Exactly. onTimer is a function that registers user event and calls
> > it with specific interval.
> >
> >  >  If so, how would you declare the cfunction
> >  > onTimer that would handle this input?
> >  Just like any other cfunction - you just handle the parameters on
> > stack in appropriate way. The tricky thing is that you can non pop and
> > store function object in C-app as you can do with strings. The
> > function has to be stored inside lua state itself. To do this, you can
> > use "registry".
> >
> >  >  Delphi examples are preferred
> >  > but C/C++ will work too =)
> >  Here is an excelent explanation, along with code examples
> >  http://www.lua.org/pil/27.3.html
> >
> >  BTW, I  thought that it might be a good idea, that event registration
> > function will return some kind of event id (integral or whatever), so
> > it can be used later to remove that event notification.
> >
> >  For example:
> >
> >  local eventId = mud.onTimer(10, someFunc);
> >  ....
> >  mud.removeEvent(eventId); -- or maybe "removeTimerEvent"?
> >  --from now on someFunc will not be called anymore
> >
> >
> >  Also there should be some functionality to allow to reset all event
> > notifications.
> >
> >
> >  > Thanks!!
> >  You are welcome :)
> >
> >  > On 12/9/05, Pavel Antokolsky aka Zigmar <zigmar@gmail.com> wrote:
> >  > > Just an idea - I think it will be much more convinient and flexible to
> >  > > register a function itself, not its name. Then, you can write
> >  > > something like:
> >  > >
> >  > > -- Every ten seconds
> >  > > mud.onTimer(10, function() npc:say("Hello") end )
> >  > >
> >  > > This system can be also extended to handle different events. For example:
> >  > > mud:onRoomEnter("main", function(who,where) npc:say("Hello, " ..
> > who.name) end )
> >  > > it can be, for example, extended to handle rooms with masks
> >  > > mud:onRoomEnter("dungeon_*",
> >  > >    function(who, where)
> >  > >        if where:name != "dungen_saferoom" then
> >  > >            local monster = mud:spawn("monster",where)
> >  > >            monter:attack(who)
> >  > >        end
> >  > >   end
> >  > > )
> >  > >
> >  > > And so on... I can't even think of all possibilites with such system :)

--
Best regards,
Zigmar

Attachment: lua_event_test.cpp
Description: Binary data

Attachment: event_test.lua
Description: Binary data