/* codepoint(s, ]) -> returns codepoints for all characters that start in the range   */
static int codepoint(lua_State *L)
/* codepoint(s, ]) -> returns codepoints for all characters that start in the range   */
static int codepoint(lua_State *L)
{
    int code;
    s = utf8_decode(s, &code);
    if (s == NULL)
      return luaL_error(L, "invalid UTF-8 code");
    lua_pushinteger(L, code);
    n++;
  }
  return n;
}