Crate shunsai 

Fast shogi legal move generation on shogi_core types.

Everything Position generates is fully legal, pawn-drop mate (打ち歩詰め) included, so a caller never filters what it is handed.

Position::legal_moves is the convenient way to take them:

use shunsai::Position;

let position = Position::startpos();
assert_eq!(position.legal_moves().len(), 30);

Position::generate_moves is the fast way. It yields one MoveSet per origin, destinations still packed as a Bitboard, so a caller that only needs to count them never builds a Move at all — and can stop early by returning ControlFlow::Break:

use core::ops::ControlFlow;
use shunsai::Position;

let position = Position::startpos();
let mut moves = 0;
let _ = position.generate_moves(|set| {
    moves += set.len();
    ControlFlow::Continue(())
});
assert_eq!(moves, 30);

Moves are played and taken back with Position::do_move and Position::undo_move, which maintain the Zobrist Position::key incrementally.

Re-exports

pub use shogi_core;

Structs

Bitboard

A set of squares, one bit per square.

MoveSetIter

Expands a MoveSet into individual Moves.

Position

A shogi position with fast do/undo and an incrementally maintained Zobrist key.

Undo

What Position::undo_move needs to restore the position a move was made in, returned by Position::do_move.

Enums

MoveSet

A group of legal moves that share an origin, as handed to Position::generate_moves.