Re: [CODE] Requesting help with lua and C

["Shane Lee" <shaneplee@...>]

On 6/17/07, Rici Lake <lua@ricilake.net> wrote:
> Perhaps I don't understand your problem sufficiently. Are you
> trying to grab the output of an arbitrary unmodified Lua
> script? Or do you simply want to run a script in a more
> controlled communications environment?

I am simply attempting to grab the output from any lua script.

> The second one can easily be accomplished by simply
> writing your own read() and write() functions, and
> letting the script call them.

The read and write functions are in C, using sockets (file
descriptors) over TCP.

> You could achieve the first goal, too, by replacing the
> entire io. library, but that's a lot of work. If your
> target environment includes some equivalent of funopen()
> (as in BSD) -- I think the Linux equivalent is called
> fopencookie()), then you can just reopen the standard
> file descriptors with new ones which invoke your functions.
> I don't know if Windows has an equivalent facility or
> what it might be, though.

Oh, I am most definately on a Linux box :-) I had given some thought
to setting environmental variables when the program begins and then
allowing both the host C program and any lua children to modify the
environs, however I am not sure of the reliability of this. I could
have simply written some functions for the lua lib that create global
buffers accessible from the C program, but I am trying to stay as
portable as possible. Providing custom lua patches for everyone who
want's to run my program is not a very nice thing to think about ;-)

So, here is basically what I want to do:
The user enters a script name and the host program checks the user's
variables, then it creates a modification for the original script
based on those variables, calls that script and then shows the output
to the user. Here is a sample:

--Output from the host
H = {[[d68c7c9f-1629-45ef-a678-6aae4298562d]]}
--Original script lines hereafter
print("Your unique user ID this session is: " .. H[1])
--End Script

So the host program would provide the contents of the table "H" and
the script would print it out. Of course, this is sort of like a
"Hello World" attempt. Future versions of this exchange would of
course utilize more output from the host program and actual functions
in the lua script.
The end result would be a C program with customizable output for
aesthetic purposes, as well as possible database management via
embedded Lua scripts.
I hope this clears things up a bit...

Thanks to Rici and Leonardo for their generous replies!
-Shane