See attachment.

bool cg_ConsoleCommand( void )
{
	static bool in_lua_prompt = false;

	// see what the command is
	wstring command = cmd_Argv(0);

	if (in_lua_prompt && command == _T("exit_lua")) {
		in_lua_prompt = false;
		cphrout << "END LUA PROMPT" << endl;
		return true;
	}

	// If we're in the lua prompt, interpret this command as
	// a lua chunk
	if (in_lua_prompt) {
		wstring line = cmd_Args();
		wstring s(command+_T(" ")+line);
		string luacommand(s.begin(), s.end());
		lua::run_stream(myLuaStateHandle, "console",
						istringstream(luacommand), cphrout, cphrout);
	}

	else if (command == _T("enter_lua")) {
		in_lua_prompt = true;
		cphrout << "BEGIN LUA PROMPT" << endl;
	}
	else {
		// Your regular command-handling code here
	}

	return true;
}

Great add-in. LUA is such a nice simple language.

Thanks for these excellent contributions lately bane. They're totally useful and practical. I'm sure much of the community appreciates it. I know I do.

I was wondering, do you have an example of this using your ipakstream code to read a script file from the pak folder?

Also, how would you implement it to run? Would you make it process a single line of the lua script per frame or would you make it process the whole script per frame?

Thanks again.

Excellent stuff Bane, and nicely timed, since the Lua folks just released a free, online version of Programming In Lua, the best source of info on Lua :)
You can find it here : http://www.lua.org/pil/
And if you can, buy a paper copy :)
Edited 8th July, 2004 19:04

Pickles - thanks for the kind word :)
Here's an example of how I setup my lua interpreter then run an init script during my game's initialization.



To answer your second question... Here's what I do. Load all the scripts you'll need before hand using lua::load_chunk, and save the resulting chunk handles somewhere (that is, load the whole script file). This doesn't actually RUN the scripts, it just reads them in, and essentially creates a function within lua that, when executed, runs the contents of that script. Then, while processing each frame, run whichever of these chunks you need to.

But say you don't want to run one of the entire chunks every frame, just one of the functions defined within it. Then you just run the chunk once so that the function gets defined, then during each frame you can call just that lua function (either through the Lua C API or through Luabind or whatever).

Basically you have a whole lot of options on how and when to run your scripts and parts of your scripts. This is just how I do it. But running a single line per frame definitely wouldn't work. First of all, it's unnecessary, since Lua is VERY fast. Second, I assume by one line you mean one lua statement. Lua's syntax is very free so one line does not correspond to one statement - it would be very difficult and senseless to write (or cannibalize) a lexer to figure out the next complete syntactic chunk of lua script.

Hopefully this makes things clearer (I probably should have include this source example in the submission).

[Edit to Add: It would probably help a lot if you take a look at the reference manual on lua.org, especially the section on the C API and what exactly a "chunk" of lua code is.]
Edited 8th July, 2004 19:28

JiuQ - Thanks, and yeah I just noticed yesterday that it's free online now. Pretty sweet - I was surprised at how well it's written.

nice code, ill try it :D

Thanks again bane! That is great info!

@Bane: you are using luabind? I played around with it a couple of months back, but since I needed threads I had to be in the head version which seemed to be irredimably broken all the time. I also found that debugging through those Boost template calls was nigh-on impossible.

I have since moved on to LuaPlus and find I am immensely more productive. While the interface is nowhere as neat as luabind (in a geeky OO sort of way) I just seem to be able to get things done for a change ;-)