Pass Mailbox instead of Game on related functions for clarity

src/search/move_ordering.rs

@@ -1,4 +1,4 @@
-use crate::{board::game::Game, movegen::r#move::Move};
+use crate::{board::mailbox::Mailbox, movegen::r#move::Move};
 
 // Rows: Aggressors (P, N, B, R, Q, K)
 // Columns: Victims (K, Q, R, B, N, P)
@@ -12,11 +12,8 @@ const MVV_LVA: [[usize; 6]; 6] = [
     [5,   4,  3,  2,  1, 0],
 ];
 
-pub fn score_by_mvv_lva(game: &Game, mv: Move) -> usize {
-    match (
-        game.mailbox.find_piece_at(mv.src),
-        game.mailbox.find_piece_at(mv.dst),
-    ) {
+pub const fn score_by_mvv_lva(mailbox: &Mailbox, mv: Move) -> usize {
+    match (mailbox.find_piece_at(mv.src), mailbox.find_piece_at(mv.dst)) {
         (Some(aggressor), Some(victim)) => MVV_LVA[aggressor.idx()][victim.idx()],
         _ => 0,
     }
@@ -36,7 +33,7 @@ mod tests {
     fn test_score_by_mvv_lva() -> Result<(), String> {
         let game = from_fen(FEN)?;
         let f3f5 = Move::new_with_type(Square::F3, Square::F5, MoveType::Capture);
-        let actual = score_by_mvv_lva(&game, f3f5);
+        let actual = score_by_mvv_lva(&game.mailbox, f3f5);
         let expected = MVV_LVA[PieceType::Queen.idx()][PieceType::Pawn.idx()];
 
         assert_eq!(expected, actual);

src/search/negamax.rs

@@ -23,7 +23,7 @@ pub fn negamax(
     let mut legal_moves = 0;
 
     let mut pseudo_legal_moves = game.board.pseudo_moves_all();
-    pseudo_legal_moves.sort_unstable_by_key(|mv| score_by_mvv_lva(&game, *mv));
+    pseudo_legal_moves.sort_unstable_by_key(|mv| score_by_mvv_lva(&game.mailbox, *mv));
 
     for mv in pseudo_legal_moves {
         game.make_move(&mv);

src/search/quiescence.rs

@@ -30,7 +30,7 @@ pub fn quiescence(game: &mut Game, mut alpha: i32, beta: i32) -> (Option<Move>,
         })
         .collect();
 
-    captures.sort_unstable_by_key(|mv| score_by_mvv_lva(&game, *mv));
+    captures.sort_unstable_by_key(|mv| score_by_mvv_lva(&game.mailbox, *mv));
 
     for mv in captures {
         game.make_move(&mv);