Function luaL_ref

extlibs/lua/src/lauxlib.c:644–662

LUALIB_API int luaL_ref (lua_State *L, int t) {
  int ref;
  if (lua_isnil(L, -1)) {
    lua_pop(L, 1);  /* remove from stack */
    return LUA_REFNIL;  /* 'nil' has a unique fixed reference */
  }
  t = lua_absindex(L, t);
  lua_rawgeti(L, t, freelist);  /* get first free element */
  ref = (int)lua_tointeger(L, -1);  /* ref = t[freelist] */
  lua_pop(L, 1);  /* remove it from stack */
  if (ref != 0) {  /* any free element? */
    lua_rawgeti(L, t, ref);  /* remove it from list */
    lua_rawseti(L, t, freelist);  /* (t[freelist] = t[ref]) */
  }
  else  /* no free elements */
    ref = (int)lua_rawlen(L, t) + 1;  /* get a new reference */
  lua_rawseti(L, t, ref);
  return ref;
}


LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {