Fenex Chess Library

A fast and reliable chess engine in Rust with full rule implementation and FEN support.

Quick Start

Add to your Cargo.toml:

[dependencies]
fenex = "0.1.10"

Basic Usage

use fenex::chess::board::board::Board;
use fenex::chess::board::coordinates::Coordinates;

// Load position from FEN
let mut board = Board::from_fen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1").unwrap();

// Make a move (e2 to e4)
board.apply_move(Coordinates::new(5, 2), Coordinates::new(5, 4)).unwrap();

// Generate all legal moves
let moves = board.generate_legal_moves();
println!("Legal moves: {}", moves.len());

// Export back to FEN
println!("Position: {}", board.to_fen());

Architecture

Coordinates

• 1-indexed system (a1 = Coordinates::new(1,1))
• Conversion to/from algebraic notation

Board

• 8x8 array representation
• FEN import/export
• Legal move validation
• Special moves (castling, en passant, promotion)

Pieces

• All standard chess pieces with proper movement rules
• Color and piece type tracking

Examples

Basic Game Setup

use fenex::chess::board::board::Board;
use fenex::chess::board::coordinates::Coordinates;

// Start new game
let mut board = Board::new();

// Or load from FEN
let mut board = Board::from_fen("r1bqkbnr/pppp1ppp/2n5/4p3/2B1P3/5N2/PPPP1PPP/RNBQK2R b KQkq - 3 3").unwrap();

Making Moves

// Move piece from e2 to e4
let from = Coordinates::new(5, 2);
let to = Coordinates::new(5, 4);
board.apply_move(from, to).unwrap();

// Check if move is legal first
let legal_moves = board.generate_legal_moves();
if legal_moves.contains(&(from, to)) {
    board.apply_move(from, to).unwrap();
}

Special Moves

// Castling (automatically moves rook)
board.apply_move(Coordinates::new(5, 1), Coordinates::new(7, 1)).unwrap();

// En passant capture
board.apply_move(Coordinates::new(5, 5), Coordinates::new(4, 6)).unwrap();

// Pawn promotion - multiple options available
// Default promotion (to Queen)
board.apply_move(Coordinates::new(1, 7), Coordinates::new(1, 8)).unwrap();

// Specific promotion options
board.promote_to_queen(Coordinates::new(1, 7), Coordinates::new(1, 8)).unwrap();
board.promote_to_rook(Coordinates::new(1, 7), Coordinates::new(1, 8)).unwrap();
board.promote_to_bishop(Coordinates::new(1, 7), Coordinates::new(1, 8)).unwrap();
board.promote_to_knight(Coordinates::new(1, 7), Coordinates::new(1, 8)).unwrap();

// Or use apply_move_with_promotion for more control
board.apply_move_with_promotion(
    Coordinates::new(1, 7),
    Coordinates::new(1, 8),
    Some(PieceType::Rook)
).unwrap();

Testing

Run the test suite:

cargo test

Contributing

1. Fork the repository
2. Create a feature branch
3. Add tests for new functionality
4. Run cargo fmt and cargo clippy
5. Submit a pull request