sage-chess

🌿🌱Sage-Chess🪴🍃

A chess engine in my own programming language!

🧐 About

This is a chess engine written in the Sage programming language. I wanted to stress-test the language and see if it could handle the high computational requirements of a chess engine. I've really enjoyed getting it to work and seeing it perform well!

📦 Features

The engine aims to be complete, with the following features:

• Move generation
• Board representation
• Board evaluation
• Alpha-beta pruning
• Bitboards
• FEN parsing
• Non-queen promotion

It's also designed to be expressive and easy to use. If you want to make a custom board state, you can do it like so:

let mut b = Board.empty();
// Add a white king and pawn on E1 and E2, respectively
b.add_piece(Piece.new(PieceType of King, Color of White, Position.E1));
b.add_piece(Piece.new(PieceType of Pawn, Color of White, Position.E2));

// Add a black king and pawn on E8 and E7, respectively
b.add_piece(Piece.new(PieceType of King, Color of Black, Position.E8));
b.add_piece(Piece.new(PieceType of Pawn, Color of Black, Position.E7));

// Move the white pawn to E4 and change the turn
b.turn(Position.E2.to(Position.E4));
// Print the board
b.println();

It's also easy to get the best move for a given board state:

// Use a standard FEN string to create a board
let mut b = Board.from_fen(&"r1bqkbnr/pppp1ppp/2n5/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 2 3");
// Print the board
b.println();
// Get the best move for the current player
let best_move = b.get_best_move();
// Print the best move
best_move.println();
// Make the best move
b.turn(best_move);
// Print the board
b.println();

So you can easily use this for whatever you need!

🚀 Quick Start

First, you'll need to follow the installation instructions for the Sage programming language. Then, you can clone the repository and start running the chess engine:

$ git clone https://github.com/adam-mcdaniel/sage-chess
$ cd sage-chess
$ sage -tc src/main.sg
$ gcc out.c -Ofast -flto -o chess
$ ./chess

📚 Importing Into Your Code

To import the chess engine into your code, simply import the src/chess.sg file. First, move the src/chess.sg file into your project directory. Then, you can import the file like so:

// file: main.sg
mod chess;
from chess import *;

Then, you can start to use the chess engine!

// file: main.sg (continued...)
let mut b = Board.from_fen(&"r1bqkbnr/pppp1ppp/2n5/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 2 3");
b.println();

// Make 10 moves, 5 for each side
for let mut j=0; j<10; j+=1; {
    // Get the best move for the current player
    let move = b.get_best_move();
    // Print the move
    move.println();
    // Make the move
    b.turn(move);
    // Print the board and the score
    b.println();
    println("Score: ", b.material_score());
}

🤝 Foreign Function Interface

The chess engine uses two C functions: one to simplify bitboard operations, and the other to get the system time in order to print the time it took to calculate the best move. The C functions are defined in the ffi.h file. The functions are as follows:

// Provides the engine with a faster way to count the number of "on" bits in a 64-bit integer
void __count_bits();

// Provides the engine with a way to get the system time
void __get_time();

These functions will automatically be compiled in when you compile the resulting out.c file generated by sage -tc src/main.sg.

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

✍️ About The Author

I'm currently a PhD student at the University of Tennessee, Knoxville. I like to make things, especially programming languages. I've written other engines before, but this is my first in my own language. I hope you enjoy it!