Documentation
¶
Overview ¶
Package chess is a go library designed to accomplish the following:
- chess game / turn management
- move validation
- PGN encoding / decoding
- FEN encoding / decoding
Using Moves
game := chess.NewGame() moves := game.ValidMoves() game.Move(moves[0])
Using Algebraic Notation
game := chess.NewGame()
game.MoveStr("e4")
Using PGN
pgn, _ := chess.PGN(pgnReader) game := chess.NewGame(pgn)
Using FEN
fen, _ := chess.FEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
game := chess.NewGame(fen)
Random Game
package main
import (
"fmt"
"math/rand"
"git.nightmare.haus/rudi/chessv2"
)
func main() {
game := chess.NewGame()
// generate moves until game is over
for game.Outcome() == chess.NoOutcome {
// select a random move
moves := game.ValidMoves()
move := moves[rand.Intn(len(moves))]
game.Move(move)
}
// print outcome and game PGN
fmt.Println(game.Position().Board().Draw())
fmt.Printf("Game completed. %s by %s.\n", game.Outcome(), game.Method())
fmt.Println(game.String())
}
Index ¶
- func FEN(fen string) (func(*Game), error)
- func PGN(r io.Reader) (func(*Game), error)
- func TagPairs(tagPairs []*TagPair) func(*Game)
- func UseNotation(n Notation) func(*Game)
- type AlgebraicNotation
- type Board
- func (b *Board) Draw() string
- func (b *Board) Flip(fd FlipDirection) *Board
- func (b *Board) MarshalBinary() (data []byte, err error)
- func (b *Board) MarshalText() (text []byte, err error)
- func (b *Board) Piece(sq Square) Piece
- func (b *Board) Rotate() *Board
- func (b *Board) SquareMap() map[Square]Piece
- func (b *Board) String() string
- func (b *Board) Transpose() *Board
- func (b *Board) UnmarshalBinary(data []byte) error
- func (b *Board) UnmarshalText(text []byte) error
- type CastleRights
- type Color
- type Decoder
- type Encoder
- type File
- type FlipDirection
- type Game
- func (g *Game) AddTagPair(k, v string) bool
- func (g *Game) Clone() *Game
- func (g *Game) Draw(method Method) error
- func (g *Game) EligibleDraws() []Method
- func (g *Game) FEN() string
- func (g *Game) GameOutcome() Outcome
- func (g *Game) GetTagPair(k string) *TagPair
- func (g *Game) GetTagPairs() []*TagPair
- func (g *Game) MarshalText() (text []byte, err error)
- func (g *Game) Move(m *Move) error
- func (g *Game) MoveStr(s string) error
- func (g *Game) MovesHistory() []*Move
- func (g *Game) OutcomeMethod() Method
- func (g *Game) Position() *Position
- func (g *Game) PositionsHistory() []*Position
- func (g *Game) RemoveTagPair(k string) bool
- func (g *Game) Resign(color Color)
- func (g *Game) String() string
- func (g *Game) UnmarshalText(text []byte) error
- func (g *Game) ValidMoves() []*Move
- type LongAlgebraicNotation
- type Method
- type Move
- type MoveTag
- type Notation
- type Outcome
- type Piece
- type PieceType
- type Position
- func (pos *Position) Board() *Board
- func (pos *Position) CastleRights() CastleRights
- func (pos *Position) Hash() [16]byte
- func (pos *Position) MarshalText() (text []byte, err error)
- func (pos *Position) Status() Method
- func (pos *Position) String() string
- func (pos *Position) Turn() Color
- func (pos *Position) UnmarshalText(text []byte) error
- func (pos *Position) Update(m *Move) *Position
- func (pos *Position) ValidMoves() []*Move
- type Rank
- type Side
- type Square
- type TagPair
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func FEN ¶
FEN takes a string and returns a function that updates the game to reflect the FEN data. Since FEN doesn't encode prior moves, the move list will be empty. The returned function is designed to be used in the NewGame constructor. An error is returned if there is a problem parsing the FEN data.
func PGN ¶
PGN takes a reader and returns a function that updates the game to reflect the PGN data. The PGN can use any move notation supported by this package. The returned function is designed to be used in the NewGame constructor. An error is returned if there is a problem parsing the PGN data.
func TagPairs ¶
TagPairs returns a function that sets the tag pairs to the given value. The returned function is designed to be used in the NewGame constructor.
func UseNotation ¶
UseNotation returns a function that sets the game's notation to the given value. The notation is used to parse the string supplied to the MoveStr() method as well as the any PGN output. The returned function is designed to be used in the NewGame constructor.
Types ¶
type AlgebraicNotation ¶
type AlgebraicNotation struct{}
AlgebraicNotation (or Standard Algebraic Notation) is the official chess notation used by FIDE. Examples: e2, e5, O-O (short castling), e8=Q (promotion)
func (AlgebraicNotation) Decode ¶
func (_ AlgebraicNotation) Decode(pos *Position, s string) (*Move, error)
Decode implements the Decoder interface.
func (AlgebraicNotation) Encode ¶
func (_ AlgebraicNotation) Encode(pos *Position, m *Move) string
Encode implements the Encoder interface.
func (AlgebraicNotation) String ¶
func (_ AlgebraicNotation) String() string
String implements the fmt.Stringer interface and returns the notation's name.
type Board ¶
type Board struct {
// contains filtered or unexported fields
}
A Board represents a chess board and its relationship between squares and pieces.
func NewBoard ¶
NewBoard returns a board from a square to piece mapping.
func (*Board) Draw ¶
Draw returns visual representation of the board useful for debugging.
func (*Board) Flip ¶
func (b *Board) Flip(fd FlipDirection) *Board
Flip flips the board over the vertical or hoizontal center line.
func (*Board) MarshalBinary ¶
MarshalBinary implements the encoding.BinaryMarshaler interface and returns the bitboard representations as a array of bytes. Bitboads are encoded in the following order: WhiteKing, WhiteQueen, WhiteRook, WhiteBishop, WhiteKnight WhitePawn, BlackKing, BlackQueen, BlackRook, BlackBishop, BlackKnight, BlackPawn
func (*Board) MarshalText ¶
MarshalText implements the encoding.TextMarshaler interface and returns a string in the FEN board format: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR
func (*Board) Piece ¶
Piece returns the piece for the given square.
func (*Board) Rotate ¶
Rotate rotates the board 90 degrees clockwise.
func (*Board) SquareMap ¶
SquareMap returns a mapping of squares to pieces. A square is only added to the map if it is occupied.
func (*Board) String ¶
String implements the fmt.Stringer interface and returns a string in the FEN board format: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR
func (*Board) Transpose ¶
Transpose flips the board over the A8 to H1 diagonal.
func (*Board) UnmarshalBinary ¶
UnmarshalBinary implements the encoding.BinaryUnmarshaler interface and parses the bitboard representations as a array of bytes. Bitboads are decoded in the following order: WhiteKing, WhiteQueen, WhiteRook, WhiteBishop, WhiteKnight WhitePawn, BlackKing, BlackQueen, BlackRook, BlackBishop, BlackKnight, BlackPawn
type CastleRights ¶
type CastleRights string
CastleRights holds the state of both sides castling abilities.
func (CastleRights) CanCastle ¶
func (cr CastleRights) CanCastle(c Color, side Side) bool
CanCastle returns true if the given color and side combination can castle, otherwise returns false.
func (CastleRights) String ¶
func (cr CastleRights) String() string
String implements the fmt.Stringer interface and returns a FEN compatible string. Ex. KQq
type Decoder ¶
Decoder is the interface implemented by objects that can decode a string into a move given the position. It is not the decoders responsibility to validate the move. An error is returned if the string could not be decoded.
type Encoder ¶
Encoder is the interface implemented by objects that can encode a move into a string given the position. It is not the encoders responsibility to validate the move.
type FlipDirection ¶
type FlipDirection int
FlipDirection is the direction for the Board.Flip method
const ( // UpDown flips the board's rank values UpDown FlipDirection = iota // LeftRight flips the board's file values LeftRight )
type Game ¶
type Game struct {
Notation Notation
TagPairs []*TagPair
Moves []*Move
Positions []*Position
Pos *Position
Outcome Outcome
Method Method
IgnoreAutomaticDraws bool
}
A Game represents a single chess game.
func GamesFromPGN ¶
GamesFromPGN returns all PGN decoding games from the reader. It is designed to be used decoding multiple PGNs in the same file. An error is returned if there is an issue parsing the PGNs.
func NewGame ¶
NewGame defaults to returning a game in the standard opening position. Options can be given to configure the game's initial state.
func (*Game) AddTagPair ¶
AddTagPair adds or updates a tag pair with the given key and value and returns true if the value is overwritten.
func (*Game) Draw ¶
Draw attempts to draw the game by the given method. If the method is valid, then the game is updated to a draw by that method. If the method isn't valid then an error is returned.
func (*Game) EligibleDraws ¶
EligibleDraws returns valid inputs for the Draw() method.
func (*Game) FEN ¶
FEN returns the FEN notation of the current position.
func (*Game) GameOutcome ¶
GameOutcome returns the game outcome.
func (*Game) GetTagPair ¶
GetTagPair returns the tag pair for the given key or nil if it is not present.
func (*Game) GetTagPairs ¶
GetTagPairs returns the game's tag pairs.
func (*Game) MarshalText ¶
MarshalText implements the encoding.TextMarshaler interface and encodes the game's PGN.
func (*Game) Move ¶
Move updates the game with the given move. An error is returned if the move is invalid or the game has already been completed.
func (*Game) MoveStr ¶
MoveStr decodes the given string in game's notation and calls the Move function. An error is returned if the move can't be decoded or the move is invalid.
func (*Game) MovesHistory ¶
MovesHistory returns the move history of the game.
func (*Game) OutcomeMethod ¶
OutcomeMethod returns the method in which the outcome occurred.
func (*Game) Position ¶
Position returns the game's current position.
func (*Game) PositionsHistory ¶
PositionsHistory returns the position history of the game.
func (*Game) RemoveTagPair ¶
RemoveTagPair removes the tag pair for the given key and returns true if a tag pair was removed.
func (*Game) Resign ¶
Resign resigns the game for the given color. If the game has already been completed then the game is not updated.
func (*Game) String ¶
String implements the fmt.Stringer interface and returns the game's PGN.
func (*Game) UnmarshalText ¶
UnmarshalText implements the encoding.TextUnarshaler interface and assumes the data is in the PGN format.
type LongAlgebraicNotation ¶
type LongAlgebraicNotation struct{}
LongAlgebraicNotation is a more computer friendly alternative to algebraic notation. This notation uses the same format as the UCI (Universal Chess Interface). Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (for promotion)
func (LongAlgebraicNotation) Decode ¶
func (_ LongAlgebraicNotation) Decode(pos *Position, s string) (*Move, error)
Decode implements the Decoder interface.
func (LongAlgebraicNotation) Encode ¶
func (_ LongAlgebraicNotation) Encode(pos *Position, m *Move) string
Encode implements the Encoder interface.
func (LongAlgebraicNotation) String ¶
func (_ LongAlgebraicNotation) String() string
String implements the fmt.Stringer interface and returns the notation's name.
type Method ¶
type Method uint8
A Method is the method that generated the outcome.
const ( // NoMethod indicates that an outcome hasn't occurred or that the method can't be determined. NoMethod Method = iota // Checkmate indicates that the game was won checkmate. Checkmate // Resignation indicates that the game was won by resignation. Resignation // DrawOffer indicates that the game was drawn by a draw offer. DrawOffer // Stalemate indicates that the game was drawn by stalemate. Stalemate // ThreefoldRepetition indicates that the game was drawn when the game // state was repeated three times and a player requested a draw. ThreefoldRepetition // FivefoldRepetition indicates that the game was automatically drawn // by the game state being repeated five times. FivefoldRepetition // FiftyMoveRule indicates that the game was drawn by the half // move clock being one hundred or greater when a player requested a draw. FiftyMoveRule // SeventyFiveMoveRule indicates that the game was automatically drawn // when the half move clock was one hundred and fifty or greater. SeventyFiveMoveRule // InsufficientMaterial indicates that the game was automatically drawn // because there was insufficient material for checkmate. InsufficientMaterial )
type Move ¶
type Move struct {
// contains filtered or unexported fields
}
A Move is the movement of a piece from one square to another.
func (*Move) HasTag ¶
HasTag returns true if the move contains the MoveTag given.
func (*Move) Promo ¶
Promo returns promotion piece type of the move.
type MoveTag ¶
type MoveTag uint16
A MoveTag represents a notable consequence of a move.
const ( // KingSideCastle indicates that the move is a king side castle. KingSideCastle MoveTag = 1 << iota // QueenSideCastle indicates that the move is a queen side castle. QueenSideCastle // Capture indicates that the move captures a piece. Capture // EnPassant indicates that the move captures via en passant. EnPassant // Check indicates that the move puts the opposing player in check. Check )
type Notation ¶
Notation is the interface implemented by objects that can encode and decode moves.
type Outcome ¶
type Outcome string
A Outcome is the result of a game.
const ( // NoOutcome indicates that a game is in progress or ended without a result. NoOutcome Outcome = "*" // WhiteWon indicates that white won the game. WhiteWon Outcome = "1-0" // BlackWon indicates that black won the game. BlackWon Outcome = "0-1" // Draw indicates that game was a draw. Draw Outcome = "1/2-1/2" )
type Piece ¶
type Piece int8
Piece is a piece type with a color.
const ( // NoPiece represents no piece NoPiece Piece = iota // WhiteKing is a white king WhiteKing // WhiteQueen is a white queen WhiteQueen // WhiteRook is a white rook WhiteRook // WhiteBishop is a white bishop WhiteBishop // WhiteKnight is a white knight WhiteKnight // WhitePawn is a white pawn WhitePawn // BlackKing is a black king BlackKing // BlackQueen is a black queen BlackQueen // BlackRook is a black rook BlackRook // BlackBishop is a black bishop BlackBishop // BlackKnight is a black knight BlackKnight // BlackPawn is a black pawn BlackPawn )
type Position ¶
type Position struct {
// contains filtered or unexported fields
}
Position represents the state of the game without reguard to its outcome. Position is translatable to FEN notation.
func (*Position) CastleRights ¶
func (pos *Position) CastleRights() CastleRights
CastleRights returns the castling rights of the position.
func (*Position) Hash ¶
Hash returns a unique hash of the position
func (*Position) MarshalText ¶
MarshalText implements the encoding.TextMarshaler interface and encodes the position's FEN.
func (*Position) Status ¶
Status returns the position's status as one of the outcome methods. Possible returns values include Checkmate, Stalemate, and NoMethod.
func (*Position) String ¶
String implements the fmt.Stringer interface and returns a string with the FEN format: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
func (*Position) UnmarshalText ¶
UnmarshalText implements the encoding.TextUnarshaler interface and assumes the data is in the FEN format.
func (*Position) Update ¶
Update returns a new position resulting from the given move. The move itself isn't validated, if validation is needed use Game's Move method. This method is more performant for bots that rely on the ValidMoves because it skips redundant validation.
Source Files
Directories