Overview

Pleco is a chess Engine & Library derived from Stockfish, written entirely in Rust.

This project is split into two crates, pleco, which contains the library functionality, and pleco_engine, which contains the UCI (Universal Chess Interface) compatible engine.

The overall goal for this project is to utilize the efficiency of Rust to create a Chess AI matching the speed of modern chess engines. For the engine, the majority of the code is a direct port of Stockfish's C++ code. See their website for more information about the engine. As such, the credit for all of the advanced algorithms used for searching, evaluation, and many others, go directly to the maintainers and authors of Stockfish. This project is for speed comparisons between the two languages, as well as for educational purposes.

• Documentation, crates.io for library functionality
• Documentation, crates.io for the Engine.

Standalone Installation and Use

To use pleco as an executable, please navigate to here and read the README.md.

Using Pleco as a Library

To use pleco inside your own Rust projects, Pleco.rs is available as a library on crates.io. Simply include the current version in your Cargo.toml:

[dependencies]
pleco = "x.x.x"

And add the following to a main.rs or lib.rs:

extern crate pleco;

As of version 0.5.0, the pleco library is available on all three Rust channels (stable, beta, nightly).

Basic Usage

Setting up a board position is extremely simple.

use pleco::{Board,Player,PieceType};

let board = Board::start_pos();
assert_eq!(board.count_piece(Player::White,PieceType::P), 8);
assert_eq!(&board.fen(),"rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1");

Creating a board from a Position

A Board can be created with any valid chess position using a valid FEN (Forsyth-Edwards Notation) String. Check out the Wikipedia article for more information on FEN Strings and their format.

let board = Board::from_fen("rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR w KQkq c6 0 2").unwrap();

Applying and Generating Moves

Moves are represented with a BitMove structure. They must be generated by a Board object directly, to be considered a valid move. Using Board::generate_moves() will generate all legal BitMoves of the current position for the current player.

use pleco::{Board,BitMove};

let mut board = Board::start_pos(); // create a board of the starting position
let moves = board.generate_moves(); // generate all possible legal moves
board.apply_move(moves[0]);
assert_eq!(board.moves_played(), 1);

We can ask the Board to apply a move to itself from a string. This string must follow the format of a standard UCI Move, in the format [src_sq][dst_sq][promo]. E.g., moving a piece from A1 to B3 would have a uci string of "a1b3", while promoting a pawn would look something like "e7e81". If the board is supplied a UCI move that is either incorrectly formatted or illegal, false shall be returned.

let mut board = Board::start_pos(); // create a board of the starting position
let success = board.apply_uci_move("e7e8q"); // apply a move where piece on e7 -> eq, promotes to queen
assert!(!success); // Wrong, not a valid move for the starting position

Undoing Moves

We can revert to the previous chessboard state with a simple Board::undo_move()

let mut board = Board::start_pos();
board.apply_uci_move("e2e4"); // A very good starting move, might I say
assert_eq!(board.moves_played(),1);
board.undo_move();
assert_eq!(board.moves_played(),0);

For more information about pleco as a library, see the pleco README.md.

Contributing

Any and all contributions are welcome! Open up a PR to contribute some improvements. Look at the Issues tab to see what needs some help.

License

The Pleco Engine is distributed under the GNU General Public License version 3 (or any later version at your option). See LICENSE for full details.

The Pleco crate (the library functionality) is distributed under the terms of the MIT license. See pleco/LICENSE for details.

Opening a pull requests is assumed to signal agreement with these licensing terms.