message: add shift function to currornext
diff: @@ -19,6 +19,15 @@ pub enum CurrOrNext {
  Next,
  }
  +impl CurrOrNext {
  + pub fn shift(&self) -> usize {
  + match self {
  + CurrOrNext::Curr => 0,
  + CurrOrNext::Next => 1,
  + }
  + }
  +}
  +
  #[derive(Clone, Copy, Debug)]
  pub struct LocalPosition {
  pub row: CurrOrNext,
  