Re: Lua C API can't be used from other languages without C wrappers

[Andrew Gierth <andrew@...>]

>>>>> "albertmcchan" == albertmcchan  <albertmcchan@yahoo.com> writes:

 albertmcchan> Had not expected calling B shared the same lua stack.
 albertmcchan> Is there a way to force calling B, C, ... with a new
 albertmcchan> stack ? (like in lua ?)

Of course there is, you use lua_pushcfuncfion and lua_call, as I pointed
out to you before.

int B(lua_State *L)
{
    lua_settop(L, 0);
    lua_pushstring(L, "foo!");
    return 1;
}

int A(lua_State *L)
{
    /* stack currently has args of A if any */
    lua_pushstring(L, "bar!");
    /* this calls B in A's stack frame, so it will clobber the
     * string pushed above and any args, leaving A's stack with
     * just B's "foo!" on it
     */
    B(L);
    /* but this calls B on a brand new stack frame of its own,
     * so the existing "foo!" remains on the stack and another
     * one is pushed on top
     */
    lua_pushcfunction(L, B);
    lua_call(L, 0, 1);  /* 0 args, 1 result */
    /* stack now has just "foo!", "foo!" */
    return 2;
}

This is how you do it if B and A both need to be independently callable
from Lua but A needs to call B.

-- 
Andrew.