bishop 1.4.1

Bishop is a chess logic package with flexible variant support.

1.4.1

• Now using Dart 3!
• Potentially breaking: FEN strings without castling rights specified now default to no castling rights, instead of all castling rights (thanks @govind-maheshwari2).
• Fixed Seirawan chess mating conditions not taking H and E into account (thanks @malaschitz).
• Fixed Chess960 castling moves not working in some cases where the rook would land on the square after the king (thanks @malaschitz).

1.4.0

• Custom move generation and processing (beta):
  • MoveGenerator: optionally supply a list of these in Variant.moveGenerators. These can be used to generate custom moves based on the state. You can generate both normal move types (e.g. add an extra move to a piece on a certain square or something), or totally different types of move that can be managed by MoveProcessor.
  • MoveProcessor: supply a list of these in Variant.moveProcessors to process custom move types.
• StateTransformer: a way to transform game states based on player perspectives.
  • Variant.stateTransformer takes a StateTransformer that defines how the state is transformed.
  • BishopState.transform([int? player]) or BuiltVariant.transformState() will return a transformed state (or the same state if there is no transformer). It's possible to define a transformer that takes player: null and transforms the state regardless of player. This option exists for cases where you always want to transform
  • VisionAreaStateTransformer applies a mask to the board based on a vision radius around pieces. MaskedState is a subclass of BishopState which contains the [mask] used to create it (for cases where e.g. you want to draw the mask on a board).
  • HideFlagsStateTransformer hides the flags for all of the player's or opponent's pieces, depending on configuration.
• King attacks are calculated in advance for mainline moves and can be accessed with state.meta!.checks!. They come in the form of a list of squares containing pieces that are attacking the king of each player.
• Game.evaluate() now takes pieces in hands into account.
• Gating move logic is no longer part of the standard move logic. GatingMove is its own type which contains a child move.
• SubtractRegion, XorRegion, SetRegion and DirectionSetRegion.
• Regions in Variant.regions are now built into a more efficient form when the variant is built.
• BoardRegions can now be combined using the +, -, & and ^ operators.
• Variants:
  • TenCubed (LargeVariants.tenCubed()): 10x10 board with fairy pieces.
  • Opulent (LargeVariants.opulent()): a variant of Grand.
  • Troitzky (ShapeVariants.troitzky()): vaguely circular shaped board.
  • Omega (ShapeVariants.omega()): experimental version - mostly working except for en-passant on long pawn moves.
  • Five Field Kono (OtherGames.kono()): win by moving all of your pieces to your opponent's start position.
  • Joust (OtherGames.joust()): the square a piece moves from is removed from the board each time it moves.
  • Wolf (FairyVariants.wolf()): an 8x10 variant with several fairy pieces.
  • Knightmate (MiscVariants.knightmate()): royal knight instead of king, common kings instead of knights.
  • Pocket Knight (MiscVariants.pocketKnight()): chess but each player has an extra knight in hand.
  • Breakthrough (OtherGames.breakthrough()): only (modified) pawns, move one to the end to win.
  • New Zealand Chess (FairyVariants.newZealand()): rooks capture like knights, knights capture like rooks.
  • Nightrider Chess (FairyVariants.nightrider()): knights are replaced with nightriders.
  • Shatranj (CommonVariants.shatranj()): an ancient form of chess.
• ActionFillRegionEnding: the end condition for Kono.
• ActionBlockOrigin: implements the behaviour for Joust.

1.3.2

• Fixed a castling bug (queenside allowed with piece on b1).
• Various minor improvements to PGN import/export.
• Improvements to example.dart: can export PGN and use the engine.
• Fixed some variants not having the 100 half-move rule when they should.
• Variants: Clobber (OtherGames.clobber()) and Clobber 10 (OtherGames.clobber10()).

1.3.1

• Further optimisation: excluding piece types early from attack checks (~20% performance boost).

1.3.0

• Bishop is now about 2x faster thanks to significant optimisations in attack checking.
• Region changes (breaking):
  • What used to be BoardRegion is now RectRegion.
  • BoardRegion is now a parent class for RectRegion and other board region types.
  • UnionRegion and IntersectRegion combine multiple BoardRegions with union and intersection respectively.
• RegionPromotion (PromotionOptions): pieces can promote in specific regions.
• RegionDropBuilder now allows using region IDs from variant, and separate regions per player (same API as RegionPromotion).
• FirstMoveOptions (breaking): replaces Variant.firstMoveRanks, supports more flexible first move options.
• First move checking for most variants no longer uses the rank of the piece. Instead there is an 'initial state' property embedded in the square representation.
  • FirstMoveOptions.ranks is still available, and is used by Horde Chess, for example, since not all horde pawns should be double moveable in their initial state.
• Betza parsing now supports (x,y) atoms, allowing for pieces jumping more than 3 squares in each direction. For example, the 'Giraffe' is (4,1), and the Knight could be rewritten as (2,1) (or (1,2)).
• Variants:
  • Legan Chess (MiscVariants.legan()): a diagonally arranged chess variant.
  • Grasshopper Chess (FairyVariants.grasshopper()): chess with some extra grasshopper pieces.
  • Berolina Chess (FairyVariants.berolina()): chess with the Berolina pawn (PieceType.berolinaPawn()).
• Fixed PGN parsing on Windows (\r related issues).
• A lot of old deprecated constants and functions have been removed.
• The default value of Variant.castlingOptions is now CastlingOptions.none.
• play.dart example: move filtering commands - moves from x, moves to x, moves captures, moves quiet.
• BoardSize.isValidSquareName(): check if a square name is valid.

1.2.10

• Variants:
  • Andernach Chess (MiscVariants.andernach()): capturing pieces change colour.
  • Jeson Mor (OtherGames.jesonMor()): knights only, win by entering the central square and leaving it again.
• ActionTransferOwnership: changes the colour of the moving piece.
• ActionExitRegionEnding: end the game when a piece leaves a region.

1.2.9

• Fixed a bug with lame leaper squares being calculated incorrectly.
• Fixed a bug where points-based games could result in draws when the opponent would win regardless next round. GameResult.soft defines result types that won't delegalise moves.
• GameResult.readable: human-readable string describing the result (e.g. 'White won by checkmate').

1.2.8

• Fixed a bug where en passant captured pieces wouldn't increment in BishopState.pieces.

1.2.7

• BishopState.capturedPieces(): used to get the captured pieces in a given state, by comparing to the initial state.

1.2.6

• Fixed an issue with parsing PGNs containing clock annotations (thanks @deathcoder).
• Variant: Antichess.
• Variant.forcedCapture: defines forced capture rule behaviour.
• GameEndConditions changes: stalemate and elimination are now of type EndType instead of bool, allowing greater flexibility (win, loss or draw).

1.2.5

• Improved efficiency when making moves from SAN strings or parsing PGNs: the check component of the SAN string can now be skipped.

1.2.4

• PieceType.withAction(), PieceType.withRegionEffect(), Variant.withAction(), Variant.withRegion() fluent helpers.
• MoveMeta.prettyName is now MoveMeta.formatted.

1.2.3

• GameNavigator: a helper class that simplifies navigating through a completed game. This is still an early form.
• PGN parsing functionality: parsePgn(), gameFromPgnData(), Game.fromPgn(), GameNavigator.fromPgn().
• State now contains a StateMeta? meta field: this contains a reference to the variant as well as string representations of moves. This will only be added to mainline moves (i.e. normal calls to makeMove, not legality check moves), so it doesn't affect speed, and improves usability.
• Fixed pawns being destroyed by explosions in Atomic Chess.
  • Explosion actions now take an optional list of immune pieces.

1.2.2

• Variant.startPosBuilder changes: now is a class (StartPositionBuilder), so it can be serialised, and start position build functions now take an optional seed.

1.2.1

• Fixed a bug that would cause hands parsed from FEN strings to be incorrect.
• Fixed a bug with side-specific oblique moves (e.g. lfN) being mirrored.
• Capturing promoted pieces now behaves as expected, the internal piece type is added to hand, as in Shogi.
• Betza shorthands f, b, l and r are now allowed for oblique moves (behaving as ff, bb, ll, rr).

1.2.0

• Refactored Move objects, and the logic responsible for making moves in Game.
  • Move is now an interface that other more specific move types implement.
  • StandardMove implements most of the behaviour that the previous Move object did.
  • DropMove for drops. PassMove for the new passing move.
  • Similarly, MoveDefinition has been abstracted in the same way, though the implementations don't directly match Move implementations.
• Slightly changed the encoding for squares:
  • Colour now has two bits, supporting up to 4 players.
  • Piece type has 8 bits instead of 7, increasing piece limit to 255.
  • A secondary piece type ('internal') is now encoded, also with 8 bits. The primary use case for this is storing the type a piece had before its promotion.
  • 14 bits for flags instead of 4. (46 if you assume your code won't execute on 32 bit vm).
• It's now possible to store custom state variables in the invisible squares outside the board. Technically, it was always possible, but it's now easier to do, and supported.
  • In actions, return an EffectSetCustomState to change a state variable. You can define a number of variables equal to the amount of squares on your board, so 64 for a standard chess board.
  • Read these from trigger.getCustomState() in triggers, or Game.getCustomState() otherwise.
• Support for 'teleport' moves, i.e. moves where the piece can move anywhere on the board. These are built with the Betza atom '*', and support 'c'/'m' modifiers.
• Experimental support for neutral pieces, i.e. pieces that can moved by either player, like the duck in duck chess. Currently the only way to use these is to define a piece with the key '*'.
• Variant.passOptions: allow pass moves, where the turn changes but nothing happens. Allows for custom conditions.
• ActionPointsEnding: leverages custom state to define a game end condition based on points.
• ActionImmortality: allows for pieces of certain types, or with certain flags, to be uncapturable.
• RegionDropBuilder: define drop rules that only allow drops within a specified region.
• Variants:
  • Orda (Orda.orda()) and Orda Mirror (Orda.ordaMirror()).
  • Domination (MiscVariants.domination()): keeping pieces in the centre of the board accumulates points for their owner.
  • Dart Chess (MiscVariants.dart()): cramped variant on a 6x6 board. Each player has 3 'darts' they can drop onto the board, which block movement and cannot be moved or captured.

1.1.2

• ActionCheckPieceCount: allows for win conditions based on elimination of arbitrary pieces.
• Variant.forbidChecks: if true, it is impossible for anyone to deliver a check.
• Variants:
  • Kinglet (MiscVariants.kinglet()): game is won when opponent has no pawns.
  • Three Kings (MiscVariants.threeKings()): players have three kings, and capturing any one results in a win.
  • Racing Kings (CommonVariants.racingKings()).

1.1.1

• Custom drop move generation is now possible with Variant.handOptions.dropBuilder.
• Added variant definitions: Mini Xiangqi (Xiangqi.mini()), Manchu (Xiangqi.manchu()), Hoppel-Poppel (FairyVariants.hoppelPoppel()), Shako (LargeVariants.shako()), Dobutsu (Dobutsu.dobutsu()).
• Fixed a bug in serialisation of pieces with limited promo options.
• Experimental (incomplete) Shogi support.
• Variant.withCampMate(): helper method to add the campmate end condition to a variant.
• Variant.withPieces() and Variant.withPiecesRemoved() helpers.
• The play example can now load JSON variants.

1.1.0

• JSON Serialisation support: Variant.fromJson() and Variant.toJson().

1.0.0

• A powerful new action system with an accessible API for creating custom game logic. Trigger actions on certain events and execute them if their conditions are met.
  • Support for Atomic Chess.
  • Xiangqi flying generals rule implemented.
• Overhaul regarding how promotion works:
  • Promotion move generation is now handled by builder functions, and can be defined in variants with PromotionOptions. This allows for more versatile promotion move generation, including cases like limiting the number of pieces of a certain type, conditional promotions, non-rank based promotion areas, etc.
  • PieceType definitions now take PiecePromoOptions object that encapsulates its promotion behaviour. It is possible to define pieces that only have specific promotion options here (e.g. like Shogi).
  • Grand chess is now working as expected.
• The state of the board is now stored in BishopState, instead of a single list in Game being modified. This improves code readability and also results in small performance improvements in most cases.
• More descriptive game results. Use Game.result to see the exact way the game ended (null if it's still ongoing). Old getters like Game.checkmate still exist but result is preferred.
• Variant.gameEndConditions now takes a GameEndConditionsSet, allowing for asymmetric end conditions.
• GameEndConditions now allows disabling stalemate (resulting in a loss for the stalemated player), and elimination losses (when all pieces are removed).
  • Support for Horde Chess.
• Variant.hands boolean option replaced with HandOptions, allowing for variants where hands are enabled but captured pieces aren't added to them (pieces can now be added through actions - see Variant.spawn() example).
• PieceType and MoveDefinition are now immutable, and are normalised with copyWith methods instead of mutation.
• Fixed a bug which would invalidate castling moves in Chess960 if the target square was the rook square, and that was attacked (thanks @malaschitz).

0.6.4

• Fixed gates being output the wrong way round in FEN strings for fixed gating variants.

0.6.3

• Added variant: King of the Hill.
• Support for win regions.
• Added examples/play.dart - interactive CLI application for playing a game.
• Convenience methods on Game - moveHistory, moveHistoryAlgebraic and moveHistorySan.

0.6.2

• Switched to standard symbols for Xiangqi, i.e. Elephants are 'B' and Horses are 'N'.

0.6.1

• Board regions and region effects - these allow custom behaviour to be defined for pieces that are in specific areas of the board, and the ability to restrict piece types to regions.
• Fixed a bug in gating move generation on non standard sized boards.
• Xiangqi support: variant and piece definitions, regions and effects.
• Fixed a bug where the SAN format for pawn captures might be wrong (thanks @malaschitz).
• Fixed Chess960 castling moves not being generated for kings on g1 (thanks @malaschitz).
• Fixed Crazyhouse bugs: pawns being droppable on the first rank, and promoted pieces not being captured as pawns (thanks @malaschitz).
• Fixed a extremely rare case where a rook on the file of another uncastled rook of the same colour would affect the castling rights of that other rook (thanks @malaschitz).

0.6.0

• Support for hopper pieces, such as the Grasshopper and Xiangqi Cannon, and Betza modifiers 'p' and 'g'.
• Fixed a bug with capture only sliding moves not generating correctly.

0.5.2

• Fixed a bug in premove generation where quiet moves to opponent occupied squares weren't generating (e.g. pawn step forward onto opponent's piece).
• Added some extension functions for List<Move>, for filtering moves more fluently.

0.5.1

• Some convenience methods on Variant: pieceSymbols and commonPieceSymbols.
• Built in CastlingOptions are now static const.
• CastlingOptions.copyWith() and MaterialConditions.copyWith();

0.5.0

• Variant is now an immutable data type, which is converted to BuiltVariant when it's used in Game.
• fenBuilder parameter in Game constructor, overrides variant.startPosBuilder.
• Game.makeMoveString() and Game.makeMultipleMoves().
• variantFromString() utility function.

0.4.0

• Improved structure and formatting of codebase.
• There are some minor breaking changes, mostly related to CONSTANT_NAMES being changed to camelCase, and otherwise being more logically grouped. Some factory constructors were also changed to static constants, e.g. MaterialConditions.standard() is now MaterialConditions.standard.

0.3.3

• Fixed flex gating not generating no-drop moves
• Added support for variants that end after a number of checks (e.g. Three-Check)

0.3.2

• Support for fixed gating (e.g. gating in Muskteeer chess)
• Support for directional modifiers for oblique pieces in Betza parser (e.g. fN is now possible)

0.3.1

• Insufficient material draws
• Improved FEN validation
• Fixed a Zobrist hashing bug (on captures)
• Various minor improvements

0.3.0

• Gating drops and the Seirawan Chess variant
• Virgin file tracking
• Lots more documentation
• Allow a custom seed to be specified (for Zobrist hashing)
• Fixed SAN for castling with check

0.2.10

• Another small variant (mini - 6x6)
• buildRandomPosition() for generating arbitrary random positions, see Variant.miniRandom for an example
• Fixed a bug in which drop moves were not being legalised
• Fixed SAN disambiguators for pawns
• Various minor improvements

0.2.9

• Fixed FEN validation for small boards
• Added some documentation

0.2.8

• Fixed another 960 castling bug (370 / BNRKRBNQ)

0.2.7

• Fixed a castling bug in some 960 positions (e.g. 938 / RKRNBBQN)

0.2.6

• Support loading incomplete FEN strings
• Game.validateFen() function
• CastlingOptions.useRookAsTarget: formats algebraic moves correctly for Chess960

0.2.5

• Premove generation
• Game.loadFen() function

0.2.4

• Fixed engine not wanting to checkmate you
• Micro variant

0.2.3

• Basic engine
• Fixed CastlingOptions assertion

0.2.2

• Mini variant
• Independent side castling (e.g. only queenside for Minichess)
• Piece values

0.2.1

• Added Game.boardSymbols(), for use with the squares package

0.2.0

• Renamed package to Bishop
• Piece drops & hands (Crazyhouse support)

0.1.1

• Zobrist hashing & repetition draws

0.1.0

• Hello Bishop