static int luaB_comemory (lua_State *L) {
  lua_State *co = lua_tothread(L, 1);
  luaL_argcheck(L, co, 1, "coroutine expected");

  size_t memory = sizeof(lua_State);

  /* Probing each individual type is ugly, but the only way that I see */
  int i;

  for (i = 1; lua_isnone(co, i) == 0; i++) {
    if (lua_isboolean(co, i)) {
      memory += sizeof(int);
    } else if (lua_iscfunction(co, i)) {
      memory += sizeof(lua_CFunction);
    } else if (lua_isfunction(co, i)) {
      memory += sizeof(Proto);
    } else if (lua_isnumber(co, i)) {
      memory += sizeof(lua_Number);
    } else if (lua_isstring(co, i)) {
      memory += lua_strlen(co, i);
    } else if (lua_istable(co, i)) {
      memory += 64; /* Temporary guess */
    } else if (lua_isthread(co, i)) {
      memory += sizeof(lua_State); /* Need to loop through thread */
    }
  }

  lua_pushinteger(L, (lua_Integer) memory);

  return 1;
}