PgnGame<T extends PgnNodeData> class

A Portable Game Notation (PGN) representation.

A PGN game is composed of PgnHeaders and moves represented by a PgnNode tree.

Parser

This class provide 2 parsers: parsePgn to create a single PgnGame and parseMultiGamePgn that can handle a string containing multiple games.

const pgn = '1. d4 d5 *';
final game = PgnGame.parsePgn(pgn);
Position position = PgnGame.startingPosition(game.headers);
for (final node in game.moves.mainline()) {
  final move = position.parseSan(node.san);
  if (move == null) break; // Illegal move
  position = position.play(move);
}

Augmenting game tree

You can use PgnNode.transform to augment all nodes in the game tree with user data.

It allows you to provide context. You update the context inside the callback. Context object itself should be immutable to prevent any unwanted mutation. In the example below, the current Position pos is provided as context.

class PgnNodeWithFen extends PgnNodeData {
  final String fen;
  const PgnNodeWithFen(
      {required this.fen,
      required super.san,
      super.startingComments,
      super.comments,
      super.nags});

   // Override == and hashCode
   // ...
}

final game = PgnGame.parsePgn('1. e4 e5 *');
final pos = PgnGame.startingPosition(game.headers);
final PgnNode<NodeWithFen> res = game.moves.transform<NodeWithFen, Position>(pos,
  (pos, data, _) {
    final move = pos.parseSan(data.san);
    if (move != null) {
      final newPos = pos.play(move);
      return (
          newPos, NodeWithFen(fen: newPos.fen, san: data.san, comments: data.comments, nags: data.nags));
    }
    return null;
  },
);

Constructors

PgnGame({required PgnHeaders headers, required PgnNode<T> moves, required List<String> comments})

Constructs a new PgnGame.

Properties

comments → List<String>

Initial comments of the game.

final

hashCode → int

The hash code for this object.

no setter, inherited

headers → PgnHeaders

Headers of the game.

final

moves → PgnNode<T>

Parent node containing the game.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

makePgn() → String

Make a PGN String from PgnGame.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

defaultHeaders() → PgnHeaders

Create default headers of a PGN.

emptyHeaders() → PgnHeaders

Create empty headers of a PGN.

parseMultiGamePgn(String pgn, {PgnHeaders initHeaders() = defaultHeaders}) → List<PgnGame<PgnNodeData>>

Parse a multi game PGN string.

parsePgn(String pgn, {PgnHeaders initHeaders() = defaultHeaders}) → PgnGame<PgnNodeData>

Parse a PGN string and return a PgnGame.

startingPosition(PgnHeaders headers, {bool? ignoreImpossibleCheck}) → Position<Position>

Create a Position for a Variant from the headers.