14:28 damir_: so, I have many objects in my c++ code, for which I want to write different ai behaviours in lua. Each behaviour script is a seperate .lua file containing the update_ai() function.
14:29 damir_: What is the best way to achieve this? Do I make new lua state for every object and compile the appropriate script every time?
14:29 Dylan343_: load each file into a function, set the environment to a blank new table, run the function
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14:30 Dylan343_: then save that table, or save the update_ai key from it
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14:30 Dylan343_: look at sandboxing on the wiki
14:34 damir_: aren't sandboxes useful for safety? I don't care for that at this point.
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14:35 doub: damir_: why do you want to use veral states then ?
14:36 doub: *several
14:36 Dylan343_: sandboxes are quite useful for unsafe isolation
14:37 damir_: I just want to decide at runtime which ai script will I use for each object
14:38 damir_: I want to have those ai functions in seperate files but under the same function name
14:38 hoelzro: damir_: I recommend Dylan343_'s approach as well
14:38 hoelzro: sandboxes are used for more than just security
14:39 hoelzro: I guess in this context it's not really a sandbox
14:39 hoelzro: but the same idea (and techniques) apply
14:39 damir_: Ok, I'll look into it, thanks
14:43 JNZ: Kinnison: How do you mean? Are you saying the number of elements returned is pushed last?
14:43 doub: damir_: sandboxing is probably over-complicated for your needs
14:44 doub: how do you select which script goes to which object ?
14:44 damir_: doub, I have my own c++ logic for that, could just be rand()
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14:44 doub: how do you identify a script, is it by filename ?
14:45 damir_: yes
14:45 doub: and do you need the update function in the script to be a global variable ?
14:46 damir_: hmm not sure about that. It just needs to have predefined name and parameters.
14:46 doub: why do you need a name ?
14:47 damir_: I'm not sure how else to feed it parameters
14:47 doub: you can put the functions in a table, and use the filename as key
14:47 damir_: otherwise I might need it if in the future the scripts contains more than one function
14:47 doub: for example in pseudo-code :
14:48 doub: my_ai_functions[filename] = function(arg1, arg2) --[[ ... ]] end
14:49 doub: if you need several functions, then it's probably easier to use a setfenv-based solution, be it modules, full-fledged sandboxing, or a simple custom solution
14:49 Kinnison: JNZ: No, you record the stack depth before and aafter
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14:50 doub: i'd pick the last, since it represent the least amount of code on your side
14:50 damir_: ok, so I do _loadfile, and then how do I get the 'pointer' to the just loaded function?
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14:51 doub: after loadfile, none of your user functions has been created
14:51 doub: you need to run the script
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14:52 damir_: right, I do that with _pcall
14:52 doub: do you load it from C code of from Lua ?
14:52 damir_: from c
14:52 doub: if you simply pcall it, the global definitions in the script will go to the shared global environment, and scripts will overwrite each other
14:53 doub: you need to redirect those writes to a table per script between the load and the pcall
14:54 doub: basically: script = loadfile(filename); globals = setmetatable({}, {__index=_G}); setfenv(script, globals); script(); my_ai_functions[filename] = globals
14:54 doub: port that to C (ask if you need help), and you should be set
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14:58 damir_: hmm why is the 'script' variable important to setfenv? It should be always 0 if loading was OK
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14:59 hoelzro: damir_: loadfile returns the function chunk
14:59 hoelzro: loadfile ~= luaL_loadfile
15:00 doub: oh, right, script is the "logical result", ie. the compiled script, not the status of lua_loadfile (but rather what it left on the stack)
15:01 VShell: script is the compiled code. calling script() will run that code.
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15:06 damir_: what's the C counterpart for loadfile?
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15:07 VShell: luaL_loadfile
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15:08 VShell: or, at a lower level, if you want to provide the source from something other than a file, lua_load
15:17 damir_: ok, I need to read some material on lua stack, tables etc :)
15:17 damir_: thanks for now
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