Re: access to lua arrays from within C code

[lhf (Luiz Henrique de Figueiredo)]

>I have a C function that expects char *argv[] as an argument.
>The natural representation for argv in Lua would be as a table
>with elements 1, 2, 3, etc.
>
>What is the recommended method of getting access to the array elements
>from within my C code?

The easiest solution is something like:

/* CAUTION: untested code ahead */

 lua_Object t=lua_getparam(1);

 for (i=0; i<N; i++)
 {
  lua_Object v;
  lua_beginblock();
  lua_pushobject(t);
  lua_pushnumber(i);
  v=lua_gettable()
  if (v==LUA_NOOBJECT || lua_isnil(v)) break;
  argv[i]=lua_getnumber(v);
  lua_endblock();
 }

 argc=i;
 myfunction(argc,argv);

Another solution is to use "call" in lua:

 function myfunction(t)
	 call(actual_myfunction,t)
 end

where the C function "myfunction" is registered in Lua as "actual_myfunction".

With this code in place, you can access the array elements in C as if they
were arguments:

 for (i=0; i<N; i++)
 {
  lua_Object v;
  v=lua_param(i)
  if (v==LUA_NOOBJECT || lua_isnil(v)) break;
  argv[i]=lua_getnumber(v);
 }

Hope this helps.
--lhf