Check Args

wiki

int luac_checkargs(lua_State *L, int count, ...)

{

  va_list ap;

  int i, t, u;

  va_start(ap, count);

  for (i = 1; i <= count; i++)

  {

    t = va_arg(ap, int);

    if (t<=LUA_TNIL) continue;

    u = lua_type(L, i);

    if (t!=u)

    {

      va_end(ap);

      return luaL_typerror(L, i, lua_typename(L, t));

    }

  }

  va_end(ap);

  if (lua_gettop(L)>count)

    return luaL_argerror (L, count+1, "too many arguments");

  return 0;

}

An example usage of this function would be as such:

static int luac_testcheckargs(lua_State *L)

{

  luac_checkargs(L, 3, LUA_TNUMBER, LUA_TNIL, LUA_TBOOLEAN);

  return 0;

}

It would be useful for overloaded functions to be able to specifically test a single argument against several types. LUA_TNIL and LUA_TNONE are used as an escape, so that this function doesn't check the type of that argument.

comments appreciated.

--WilliamBubel