Re: Solved: thks - Unable to access table using lua after creation of table in C

["Dr Christopher S Kirk" <drcskirk@...>]

Thank you very much for your observations.

I had in fact tried this solution and still failed.

I reworked a test script and achieved success.

The reason for the failure appears to be that I wrapped the solution
inside another 'C' function which had not been registered in the correct
form for use bu lua.  This suggests that scoping is more stringent than
I had thought and propagation of mixed functions across the code is
difficult.

This is embarrassing and I apologise if I wasted time.

The solution will form part of work to handle raw packet analysis.  I
will announce progress when further work has been accomplished.

Many thanks

Chris

On Wed, 11 Mar 2009 15:28:06 +0000 (UTC), "Dolphin"
<dhawkins@netstreams.com> said:
> I would suggest looking at http://www.lua.org/pil/24.2.html (The Stack). 
> Most
> of the lua C API operates on values on the stack.  I use
> http://pgl.yoyo.org/luai/i/_
> as a reference when I need to remember what the functions do.  Stack
> programming
> takes a bit of getting used to, and some of the lua C api may do thinks
> you are
> not expecting until you get a bit more comfortable with it.
> 
> To create a new global table named "tablename" in C you can do:
> 
> lua_newtable(L);                    //[{}]
> lua_setglobal(L, "tablename");      //
> 
> If you want to create the table AND add a c function to it.
> 
> lua_newtable(L);                    //[{}]
> lua_pushcfunction(L, someFunc);     //[somefunc, {}]
> lua_setfield(L, -2, "someFuncName");//[{somefuncName=somefunc}]
> lua_setglobal(L, "tablename");      //[]
> 
> if you need to access an existing table and add a c function:
> lua_getglobal(L, "tablename");      //[{}]
> lua_pushcfunction(L, someFunc);     //[somefunc, {}]
> lua_setfield(L, -2, "someFuncName");//[{somefuncName=somefunc}]
> lua_pop(L, 1);                      //[]
> 
> When I first started writing lua C code it helped me to put in comments
> what the
> stack looks like after every command.  
> 
> 
-- 
Dr Christopher S Kirk

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