chessie

Chessie

A (work-in-progress) fast chess library suitable for use in chess engines.

Overview

This library provides a clean, easy-to-use API for creating and working with chess games. It supports Forsyth-Edwards Notation (FEN) strings for creating positions, as well as Universal Chess Interface (UCI) notation for pieces, squares, moves, and more.

One major goal of mine for this project was to include documentation tests for every function. As a result, nearly every function in this library has examples of how to use them that double as unit tests.

Examples

Only generate moves from specific squares (Knights, in this case):

let game = Game::default(); // Default starting position
let mask = game.knights(Color::White);
for mv in game.iter().only_moves_from(mask) {
    print!("{mv} ");
}
// b1a3 b1c3 g1f3 g1h3

Only generate moves that capture enemy pieces:

let game = Game::from_fen("r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1").unwrap();
for mv in game.iter().only_captures() {
    print!("{mv} ");
}
// e2a6 g2h3 f3h3 f3f6 d5e6 e5g6 e5d7 e5f7

Features

Several state-of-the-art chess programming ideas have been incorporated into this library, as well as several Rust-specific paradigms.

Current

• User-friendly, heavily-documented, easy-to-read, safe API.
• (Almost) every function has examples in its documentation.
• Ability to create, modify, and read chess positions.
• Compact representation of primitive types such as squares (8 bits) and moves (16 bits).
• Move generation API through Rust's Iterator trait, and allow generation of moves to/from specific squares (such as only generating moves for pawns, or only generating captures).
• Bitboards for piece layout and move generation.
• Magic Bitboards for sliding piece move generation.
• And many more that I may have neglected to mention

Future

• Support for parsing/writing Extended Position Description (EPD).
• Support for parsing/writing Portable Game Notation (PGN).
• Support for parsing/writing Standard Algebraic Notation (SAN).
• Chess960 support.
• Support for other variants, like Horde Chess.
• Proper support for un-making moves.
• General optimizations. See the "Issues" tab for more.

Acknowledgements:

Special thanks in particular to:

• Sebastian Lague, for his chess programming series on YouTube that ultimate inspired me to do this project.
• The Chess Programming Wiki, and all those who contribute to free, open-source knowledge.
• The folks over at the Engine Programming Discord, for their patience with my silly questions and invaluable help overall.
• Analog-Hors, for an excellent article on magic bitboards