go-chess-models, v1.0

The library that implements checking and generating of chess moves.

Major version.

Features

• representing the board as an associative array of pieces with their positions as keys;
• immutable applicating moves to the board via copying the latter;
• universal checkings of moves;
• generating moves via filtering from all possible ones;
• using an abstraction of a piece.

Installation

$ go get github.com/thewizardplusplus/go-chess-models

Examples

chessmodels.Board.CheckMove():

package main

import (
    "fmt"

    models "github.com/thewizardplusplus/go-chess-models"
)

type MockPiece struct {
    kind      models.Kind
    color     models.Color
    position  models.Position
    checkMove func(move models.Move, board models.Board) bool
}

func (piece MockPiece) Kind() models.Kind {
    return piece.kind
}

func (piece MockPiece) Color() models.Color {
    return piece.color
}

func (piece MockPiece) Position() models.Position {
    return piece.position
}

func (piece MockPiece) ApplyPosition(position models.Position) models.Piece {
    return MockPiece{
        kind:      piece.kind,
        color:     piece.color,
        position:  position,
        checkMove: piece.checkMove,
    }
}

func (piece MockPiece) CheckMove(move models.Move, board models.Board) bool {
    if piece.checkMove == nil {
        panic("not implemented")
    }

    return piece.checkMove(move, board)
}

func main() {
    board := models.NewBoard(models.Size{Width: 5, Height: 5}, []models.Piece{
        MockPiece{
            color:     models.Black,
            position:  models.Position{File: 2, Rank: 2},
            checkMove: func(move models.Move, board models.Board) bool { return false },
        },
        MockPiece{
            color:     models.White,
            position:  models.Position{File: 3, Rank: 3},
            checkMove: func(move models.Move, board models.Board) bool { return true },
        },
    })

    moveOne := models.Move{
        Start:  models.Position{File: 2, Rank: 2},
        Finish: models.Position{File: 3, Rank: 3},
    }
    fmt.Printf("%+v: %v\n", moveOne, board.CheckMove(moveOne))

    moveTwo := models.Move{
        Start:  models.Position{File: 3, Rank: 3},
        Finish: models.Position{File: 2, Rank: 2},
    }
    fmt.Printf("%+v: %v\n", moveTwo, board.CheckMove(moveTwo))

    // Output:
    // {Start:{File:2 Rank:2} Finish:{File:3 Rank:3}}: illegal move
    // {Start:{File:3 Rank:3} Finish:{File:2 Rank:2}}: <nil>
}

chessmodels.Board.ApplyMove():

package main

import (
    "fmt"
    "sort"

    models "github.com/thewizardplusplus/go-chess-models"
)

type MockPiece struct {
    kind      models.Kind
    color     models.Color
    position  models.Position
    checkMove func(move models.Move, board models.Board) bool
}

func (piece MockPiece) Kind() models.Kind {
    return piece.kind
}

func (piece MockPiece) Color() models.Color {
    return piece.color
}

func (piece MockPiece) Position() models.Position {
    return piece.position
}

func (piece MockPiece) ApplyPosition(position models.Position) models.Piece {
    return MockPiece{
        kind:      piece.kind,
        color:     piece.color,
        position:  position,
        checkMove: piece.checkMove,
    }
}

func (piece MockPiece) CheckMove(move models.Move, board models.Board) bool {
    if piece.checkMove == nil {
        panic("not implemented")
    }

    return piece.checkMove(move, board)
}

type ByPosition []models.Piece

func (group ByPosition) Len() int {
    return len(group)
}

func (group ByPosition) Swap(i, j int) {
    group[i], group[j] = group[j], group[i]
}

func (group ByPosition) Less(
    i, j int,
) bool {
    a := group[i].Position()
    b := group[j].Position()
    if a.File == b.File {
        return a.Rank < b.Rank
    }

    return a.File < b.File
}

func main() {
    board := models.NewBoard(models.Size{Width: 5, Height: 5}, []models.Piece{
        MockPiece{
            kind:     models.Rook,
            position: models.Position{File: 2, Rank: 2},
        },
        MockPiece{
            kind:     models.Bishop,
            position: models.Position{File: 3, Rank: 3},
        },
    })
    pieces := board.Pieces()
    sort.Sort(ByPosition(pieces))
    fmt.Printf("%+v\n", pieces)

    updatedBoard := board.ApplyMove(models.Move{
        Start:  models.Position{File: 3, Rank: 3},
        Finish: models.Position{File: 2, Rank: 2},
    })
    updatedPieces := updatedBoard.Pieces()
    sort.Sort(ByPosition(updatedPieces))
    fmt.Printf("%+v\n", updatedPieces)

    // Output:
    // [{kind:2 color:0 position:{File:2 Rank:2} checkMove:<nil>} {kind:3 color:0 position:{File:3 Rank:3} checkMove:<nil>}]
    // [{kind:3 color:0 position:{File:2 Rank:2} checkMove:<nil>}]
}

Repository

Link: https://github.com/thewizardplusplus/go-chess-models/tree/v1.0.

Content: code.

License: MIT.