Position<T extends Position<T>> class abstract

A base class for playable chess or chess variant positions.

See Chess for a concrete implementation of standard rules.

Implementers
Annotations
  • @immutable

Constructors

Position({required Board board, Pockets? pockets, required Side turn, required Castles castles, Square? epSquare, required int halfmoves, required int fullmoves})
const

Properties

board → Board
Piece positions on the board.
final
castles → Castles
Castling paths and unmoved rooks.
final
checkers → SquareSet
SquareSet of pieces giving check.
no setter
epSquare → Square?
En passant target square.
final
fen → String
Gets the FEN string of this position.
no setter
fullmoves → int
Current move number.
final
halfmoves → int
Number of half-moves since the last capture or pawn move.
final
hashCode → int
The hash code for this object.
no setteroverride
hasSomeLegalMoves → bool
Tests if the position has at least one legal move.
no setter
isCheck → bool
Tests if the king is in check.
no setter
isCheckmate → bool
Tests for checkmate.
no setter
isGameOver → bool
Tests if the game is over.
no setter
isInsufficientMaterial → bool
Tests if both Side have insufficient winning material.
no setter
isStalemate → bool
Tests for stalemate.
no setter
isVariantEnd → bool
Checks if the game is over due to a special variant end condition.
no setter
legalDrops → SquareSet
Gets all the legal drops of this position.
no setter
legalMoves → IMap<Square, SquareSet>
Gets all the legal moves of this position.
no setter
outcome → Outcome?
The outcome of the game, or null if the game is not over.
no setter
ply → int
Gets the current ply.
no setter
pockets → Pockets?
Pockets in chess variants like Crazyhouse.
final
rule → Rule
The Rule of this position.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
turn → Side
Side to move.
final
variantOutcome → Outcome?
Tests special variant winning, losing and drawing conditions.
no setter

Methods

hasInsufficientMaterial(Side side) → bool
Tests if a Side has insufficient winning material.
isLegal(Move move) → bool
Tests a move for legality.
kingAttackers(Square square, Side attacker, {SquareSet? occupied}) → SquareSet
Attacks that a king on square would have to deal with.
legalMovesOf(Square square) → SquareSet
Gets the legal moves for that Square.
makeSan(Move move) → (Position<T>, String)
Returns the SAN of this Move and the updated Position.
makeSanUnchecked(Move move) → (Position<T>, String)
Returns the SAN of this Move and the updated Position, without checking if the move is legal.
normalizeMove(NormalMove move) → Move
Returns the normalized form of a NormalMove to avoid castling inconsistencies.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
parseSan(String sanString) → Move?
Parses a move in Standard Algebraic Notation.
play(Move move) → Position<T>
Plays a move and returns the updated Position.
playToSan(Move move) → (Position<T>, String)
Returns the SAN representation of the Move with the updated Position.
playUnchecked(Move move) → Position<T>
Plays a move without checking if the move is legal and returns the updated Position.
toSan(Move move) → String
Returns the SAN of this Move from the current Position.
toString() → String
A string representation of this object.
override
validate({bool? ignoreImpossibleCheck}) → void
Checks the legality of this position.

Operators

operator ==(Object other) → bool
The equality operator.
override

Static Methods

initialPosition(Rule rule) → Position<Position>
Returns the initial Position for the corresponding Rule.
setupPosition(Rule rule, Setup setup, {bool? ignoreImpossibleCheck}) → Position<Position>
Create a Position from a Setup and Rule.