diff options
Diffstat (limited to 'src/board.rs')
| -rw-r--r-- | src/board.rs | 60 |
1 files changed, 58 insertions, 2 deletions
diff --git a/src/board.rs b/src/board.rs index 500241f..51a2593 100644 --- a/src/board.rs +++ b/src/board.rs @@ -1,6 +1,6 @@ use std::{fmt::Display}; -type Pos = (u8, u8); +pub type Pos = (u8, u8); pub enum PieceType { @@ -20,7 +20,7 @@ impl Display for PieceType } } -#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] +#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] pub struct GameBoard { sheep_mask: u32, @@ -53,6 +53,42 @@ pub enum Move MoveTiger{from: Pos, to: Pos} } +/// A point in chess-style notation: files `a`–`e` for x 0–4, ranks `5`–`1` for y 0–4 +/// (so y = 0, drawn at the top, is rank 5). +pub fn pos_name((x, y): Pos) -> String +{ + format!("{}{}", (b'a' + x) as char, 5 - y) +} + +/// True for a tiger move of two points, which always jumps (and kills) a sheep. +pub fn is_jump(mv: Move) -> bool +{ + match mv + { + Move::MoveTiger { from: (fx, fy), to: (tx, ty) } => fx.abs_diff(tx) == 2 || fy.abs_diff(ty) == 2, + _ => false, + } +} + +/// Chess-like notation: `s<pos>` places a sheep, `s<from><to>` moves one, +/// `t<from><to>` moves a tiger and `t<from>x<to>` is a tiger jump. +impl Display for Move +{ + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result + { + match *self + { + Move::PlaceSheep { pos } => write!(f, "s{}", pos_name(pos)), + Move::MoveSheep { from, to } => write!(f, "s{}{}", pos_name(from), pos_name(to)), + Move::MoveTiger { from, to } => + { + let x = if is_jump(*self) { "x" } else { "" }; + write!(f, "t{}{x}{}", pos_name(from), pos_name(to)) + } + } + } +} + /// Why `check_move` rejected a move. #[derive(Clone, Copy, Debug, PartialEq, Eq)] pub enum MoveError @@ -458,6 +494,26 @@ mod tests fn is_sheep(board: &GameBoard, pos: Pos) -> bool { matches!(board.get(pos), PieceType::Sheep) } fn is_empty(board: &GameBoard, pos: Pos) -> bool { matches!(board.get(pos), PieceType::Empty) } + // --- notation --- + + #[test] + fn pos_name_uses_files_and_ranks() + { + assert_eq!(pos_name((0, 4)), "a1"); + assert_eq!(pos_name((0, 0)), "a5"); + assert_eq!(pos_name((4, 4)), "e1"); + assert_eq!(pos_name((2, 2)), "c3"); + } + + #[test] + fn move_display_is_chess_like() + { + assert_eq!(Move::PlaceSheep { pos: (2, 2) }.to_string(), "sc3"); + assert_eq!(Move::MoveSheep { from: (2, 2), to: (2, 3) }.to_string(), "sc3c2"); + assert_eq!(Move::MoveTiger { from: (0, 0), to: (1, 1) }.to_string(), "ta5b4"); + assert_eq!(Move::MoveTiger { from: (0, 0), to: (2, 2) }.to_string(), "ta5xc3"); + } + // --- bit_idx / get / set --- #[test] |