dartchess

• Introduces parseMultiGameLazy and PgnLazyGame for lazy parsing of PGN files. These APIs allow you to iterate through games in a PGN file without parsing the moves (only the headers).

Breaking changes:

• Remove fast_immutable_collections dependency. Public APIs that previously returned IMap or IList now return standard Dart collections:
  • Position.legalMoves returns Map<Square, SquareSet> (was IMap<Square, SquareSet>)
  • Board.materialCount returns ByRole<int> / Map<Role, int> (was IMap<Role, int>)
  • Castles.rooksPositions returns BySide<ByCastlingSide<Square?>> / Map (was IMap-backed)
  • Castles.paths returns BySide<ByCastlingSide<SquareSet>> / Map (was IMap-backed)
  • PgnComment.shapes returns List<PgnCommentShape> (was IList<PgnCommentShape>)
  • makeLegalMoves() returns Map<Square, Set<Square>> (was IMap<Square, ISet<Square>>)
  • The BySide<T>, ByRole<T>, and ByCastlingSide<T> typedefs are now aliases for standard Map types.
• Pockets.value is removed; use Pockets.of(side, role), Pockets.count(role), Pockets.size, Pockets.hasQuality(side), and Pockets.hasPawn(side) instead.

The Position class remains completely immutable. Only the return types of some methods have changed to use standard Dart collections instead of immutable collections.

• Fix Crazyhouse.isGameOver and Crazyhouse.isCheckmate in positions where all legal moves are drop moves.

• Add SquareSet explosionSquares(Move move) method to Atomic class.

• Fix a bug in Horde.hasInsufficientMaterial that would cause a stack overflow if only one pawn was left.
• Fix insufficient material detection when the Horde has a lone Queen.
• Horde positions where the king is white instead of black are now correctly considered invalid.

• Fix an en passant bug in crazyhouse and atomicchess variants. Now the perft tests cover these variants as well.

• Add the current FEN information to PlayException messages.

• Rename makeLegalMove parameter isChess960 to includeAlternateCastlingMoves and invert its meaning. It now defaults to false.

• Remove the type parameter from Position class.
• Update dependencies.

• Fixes castling rights parsing from FEN.
• The FEN parser and writer now preserve syntactically valid castling rights even if there is no matching rook or king. Rename unmovedRooks to castlingRights.

• Fixes bugs in the PGN parser.

• PieceKind is now an enum.

Breaking changes:

• Square is now an extension type.
• Introduce File and Rank types.

Bug fixes:

• Fix Position.isLegal that was generating illegal king moves.
• Fix Position.normalizeMove that could turn an illegal move into a legal castling move.

• Add Piece.kind, Role.letter and Role.uppercaseLetter getters.

• Migrate SquareSet to an extension type.

• Upgrade fast_immutable_collections to version 10.0.0.

• Rename Rules to Rule and add rule getter to Position

• Fix parsing PGN from smartchess

• Add new ply getter to Position
• PgnNodeData is no longer specified as immutable
• Make PgnComment really immutable

• Add PgnNodeData as a bound to PgnNode generic type parameter

• rename Headers to PgnHeaders for consistency
• PgnGame isn't a const constructor anymore
• tweak parseMultiGamePgn signature for consistency

• add makeSan and makeSanUnchecked methods to the Position class.
• toSan and playToSan are now deprecated.

• Initial version.