  for _, r00 := range rt.R00 {   for r := rune(r00.Lo); r <= rune(r00.Hi); r += rune(r00.Stride) {    fn(r)   }  }  for _, r00 := range rt.R00 {   for r := rune(r00.Lo); r <= rune(r00.Hi); r += rune(r00.Stride) {    fn(r)   }  } 