Function getfunc

third-party/lua-5.1.5/src/lbaselib.c:117–130

static void getfunc (lua_State *L, int opt) {
  if (lua_isfunction(L, 1)) lua_pushvalue(L, 1);
  else {
    lua_Debug ar;
    int level = opt ? luaL_optint(L, 1, 1) : luaL_checkint(L, 1);
    luaL_argcheck(L, level >= 0, 1, "level must be non-negative");
    if (lua_getstack(L, level, &ar) == 0)
      luaL_argerror(L, 1, "invalid level");
    lua_getinfo(L, "f", &ar);
    if (lua_isnil(L, -1))
      luaL_error(L, "no function environment for tail call at level %d",
                    level);
  }
}


static int luaB_getfenv (lua_State *L) {