Swiftpack.co - Package - nvzqz/Sage

Deprecated

This project is no longer in development. I am currently developing a chess engine, Hexe. It is written in Rust, which is very similar to Swift in many ways.

Sage is not a chess engine; it's a move generator. Hexe, on the other hand, is able to both generate moves and evaluate them.


Sage

Swift 2.2 | 3.0 Platforms Gitter Apache 2.0 License

CocoaPods Carthage Swift Package Manager Documented

Sage is a cross-platform chess library for Swift.

Development happens in the develop branch.

Build Status

| Branch | Status | | :-------: | :----: | | master | Build Status | | develop | Build Status |

Features

  • [x] Chess game management
  • [x] Chess board structuring
  • [x] Move generation / validation
  • [x] En passant and castling
  • [x] Pawn promotions
  • [x] FEN for games and boards
  • [x] PGN parsing and exporting
  • [x] Documentation

Installation

Compatibility

  • Platforms:
    • macOS 10.9+
    • iOS 8.0+
    • watchOS 2.0+
    • tvOS 9.0+
    • Linux
  • Xcode 7.3 and 8.0
  • Swift 2.2 and 3.0

Install Using Swift Package Manager

The Swift Package Manager is a decentralized dependency manager for Swift.

  1. Add the project to your Package.swift.

    import PackageDescription
    
    let package = Package(
        name: "MyAwesomeProject",
        dependencies: [
            .Package(url: "https://github.com/nvzqz/Sage.git",
                     majorVersion: 2)
        ]
    )
    
  2. Import the Sage module.

    import Sage
    

Install Using CocoaPods

CocoaPods is a centralized dependency manager for Objective-C and Swift. Go here to learn more.

  1. Add the project to your Podfile.

    use_frameworks!
    
    pod 'Sage', '~> 2.0.0'
    

    If you want to be on the bleeding edge, replace the last line with:

    pod 'Sage', :git => 'https://github.com/nvzqz/Sage.git'
    
  2. Run pod install and open the .xcworkspace file to launch Xcode.

  3. Import the Sage framework.

    import Sage
    

Install Using Carthage

Carthage is a decentralized dependency manager for Objective-C and Swift.

  1. Add the project to your Cartfile.

    github "nvzqz/Sage"
    
  2. Run carthage update and follow the additional steps in order to add Sage to your project.

  3. Import the Sage framework.

    import Sage
    

Install Manually

  1. Download and drop the /Sources folder into your project.

  2. Congratulations!

Usage

Game Management

Running a chess game can be as simple as setting up a loop.

import Sage

let game = Game()

while !game.isFinished {
    let move = ...
    try game.execute(move: move)
}

Move Execution

Moves for a Game instance can be executed with execute(move:) and its unsafe (yet faster) sibling, execute(uncheckedMove:).

The execute(uncheckedMove:) method assumes that the passed move is legal. It should only be called if you absolutely know this is true. Such a case is when using a move returned by availableMoves(). Otherwise use execute(move:), which checks the legality of the passed move.

Move Generation

Sage is capable of generating legal moves for the current player with full support for special moves such as en passant and castling.

  • availableMoves() will return all moves currently available.

  • movesForPiece(at:) will return all moves for a piece at a square.

  • movesBitboardForPiece(at:) will return a Bitboard containing all of the squares a piece at a square can move to.

Move Validation

Sage can also validate whether a move is legal with the isLegal(move:) method for a Game state.

The execute(move:) family of methods calls this method, so it would be faster to execute the move directly and catch any error from an illegal move.

Undo and Redo Moves

Move undo and redo operations are done with the undoMove() and redoMove() methods. The undone or redone move is returned.

To just check what moves are to be undone or redone, the moveToUndo() and moveToRedo() methods are available.

Promotion Handling

The execute(move:promotion:) method takes a closure that returns a promotion piece kind. This allows for the app to prompt the user for a promotion piece or perform any other operations before choosing a promotion piece kind.

try game.execute(move: move) {
    ...
    return .queen
}

The closure is only executed if the move is a pawn promotion. An error is thrown if the promotion piece kind cannot promote a pawn, such as with a king or pawn.

A piece kind can also be given without a closure. The default is a queen.

try game.execute(move: move, promotion: .queen)

Pretty Printing

The Board and Bitboard types both have an ascii property that can be used to print a visual board.

let board = Board()

board.ascii
//   +-----------------+
// 8 | r n b q k b n r |
// 7 | p p p p p p p p |
// 6 | . . . . . . . . |
// 5 | . . . . . . . . |
// 4 | . . . . . . . . |
// 3 | . . . . . . . . |
// 2 | P P P P P P P P |
// 1 | R N B Q K B N R |
//   +-----------------+
//     a b c d e f g h

board.occupiedSpaces.ascii
//   +-----------------+
// 8 | 1 1 1 1 1 1 1 1 |
// 7 | 1 1 1 1 1 1 1 1 |
// 6 | . . . . . . . . |
// 5 | . . . . . . . . |
// 4 | . . . . . . . . |
// 3 | . . . . . . . . |
// 2 | 1 1 1 1 1 1 1 1 |
// 1 | 1 1 1 1 1 1 1 1 |
//   +-----------------+
//     a b c d e f g h

Forsyth–Edwards Notation

The Game.Position and Board types can both generate a FEN string.

let game = Game()

game.position.fen()
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

game.board.fen()
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR

They can also be initialized from a FEN string.

assert(Board(fen: game.board.fen()) == game.board)

assert(Game.Position(fen: game.position.fen()) == game.position)

Iterating Through a Board

The Board type conforms to Sequence, making iterating through its spaces seamless.

for space in Board() {
    if let piece = space.piece {
        print("\(piece) at \(space.square)")
    }
}

Squares to Moves

Sequence and Square have two methods that return an array of moves that go from/to self to/from the parameter.

[.a1, .h3, .b5].moves(from: .b4)
// [b4 >>> a1, b4 >>> h3, b4 >>> b5]

[.c3, .d2, .f1].moves(to: .a6)
// [c3 >>> a6, d2 >>> a6, f1 >>> a6]

Square.d4.moves(from: [.c2, .f8, .h2])
// [c2 >>> d4, f8 >>> d4, h2 >>> d4]

Square.a4.moves(to: [.c3, .d4, .f6])
// [a4 >>> c3, a4 >>> d4, a4 >>> f6]

Playground Usage

To use Sage.playground, first open Sage.xcodeproj and build the OS X target. You can then use the playground from within the project.

Board Quick Look

Board conforms to the CustomPlaygroundQuickLookable protocol.

Playground quick look

Donation

I work on this in my free time and do my best to make it as great as it can be. If you want to help me keep pushing out awesome libraries like this, a donation would be greatly appreciated. :smile:

paypal

License

Sage is published under version 2.0 of the Apache License.

Github

link
Stars: 334
Help us keep the lights on

Dependencies

Used By

Total: 0

Releases

v2.5.2 - Sep 22, 2016

Release Notes

Fixes

  • Fixes issue regarding legal move generation for king in check due to error in moves available for the attacking piece

v2.5.1 - Aug 18, 2016

Release Notes

Fixes

  • Swift 3 preview 6 and Xcode 8 beta 6 compatibility

v2.5.0 - Aug 17, 2016

Release Notes

New Features

  • Added pinned(for:) method to Board
  • Added between(_:), isBetween(start:end:) and line(with:) methods to Square
  • Added hasMoreThanOne to Bitboard

Enhancements

  • Made legal move generation/checking faster for king pieces

Fixes

  • Fixed conditions for castling so that a king cannot castle in check and it can't castle through squares that are being attacked

v2.4.1 - Aug 8, 2016

Release Notes

Fixes

  • Swift 3 preview 4 and Xcode 8 beta 4 compatibility

v2.4.0 - Aug 6, 2016

Release Notes

New Features

  • Added init(position:whitePlayer:blackPlayer:variant:) to Game #7

Enhancements

  • Greatly improved performance of attackers(to:color:) method for Board
  • Improved performance for pieceCount(for:) for Board
  • Improved performance for contains(_:) for Bitboard