Hexchess

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PHP ​

Install with the following command.

sh
composer require bedard/hexchess

Basic usage ​

The Hexchess class is a deserialized version of Forsyth–Edwards Notation. It contains the board state, current turn, en passant, and move numbers. Since castling is not a part of hexagonal chess, that section is omitted.

To create a game at the starting position, use Hexchess::init().

php
use Bedard\Hexchess\Hexchess;

$hexchess = Hexchess::init();

Hexchess instances have the following shape. The board represents an array of piece values, sorted in FEN-order.

ts
{
  board: [
    'b',  'q',  'b',  'k',  'n',  null, 'b',  null, 'n',  'r',
    null, null, null, null, null, 'r',  'p',  'p',  'p',  'p',
    'p',  'p',  'p',  'p',  'p',  null, null, null, null, null,
    null, null, null, null, null, null, null, null, null, null,
    null, 'P',  null, null, null, null, null, null, null, null,
    null, 'P',  null, 'P',  null, null, null, null, null, null,
    null, 'P',  null, 'B',  null, 'P',  null, null, null, null,
    null, 'P',  null, null, 'B',  null, null, 'P',  null, null,
    null, 'P',  'R',  'N',  'Q',  'B',  'K',  'N',  'R',  'P',
    null
  ],
  turn: 'w',
  ep: null,
  halfmove: 0,
  fullmove: 1
}

The following constants are also available on Bedard\Hexchess\Constants

  • EMPTY_POSITION

    1/3/5/7/9/11/11/11/11/11/11 w - 0 1

  • INITIAL_POSITION

    b/qbk/n1b1n/r5r/ppppppppp/11/5P5/4P1P4/3P1B1P3/2P2B2P2/1PRNQBKNRP1 w - 0 1

Available methods ​

apply ​

Apply a whitespace separated sequence of moves.

php
$hexches = Hexchess::init();

$hexchess->apply('g4g5 e7e6 f5f6 e6f6');

(string) $hexchess; // 'b/qbk/n1b1n/r5r/ppp1ppppp/5p5/6P4/4P6/3P1B1P3/2P2B2P2/1PRNQBKNRP1 w - 0 3'

applyMove ​

Apply a single move from string or San.

php
$hexches = Hexchess::init();

$hexchess->applyMove('g4g6');

(string) $hexchess; // 'b/qbk/n1b1n/r5r/ppppppppp/11/5PP4/4P6/3P1B1P3/2P2B2P2/1PRNQBKNRP1 b - 0 1'

applyMoveUnsafe ​

Apply a single move from string or San, regardless of turn or legality.

php
$hexches = Hexchess::init();

$hexchess->applyMoveUnsafe('b1b6');

(string) $hexchess; // 'b/qbk/n1b1n/r5r/ppppppppp/1P9/5P5/4P1P4/3P1B1P3/2P2B2P2/2RNQBKNRP1 b - 0 1'

clone ​

Deeply clone a Hexchess instance.

php
$hexches = Hexchess::init();

$clone = $hexchess->clone();

$hexchess === $clone; // false

currentMoves ​

Get all current legal moves.

php
$hexchess = new Hexchess('1/3/5/7/9/11/5P5/11/11/11/11 w - 0 1');

$moves = $hexchess->currentMoves();

array_map('strval', $moves); // ['f5f6, 'f5f7', ...]

findKing ​

Find FEN index for king belonging to Color.

php
$hexchess = Hexchess::init();

$hexchess->findKing('b'); // 3
$hexchess->findKing('w'); // 86

get ​

Get board value from position name.

php
$hexchess = Hexchess:init();

$hexchess->get('e1'); // 'Q'

getColor ​

Get all board indices occupied by Color pieces.

php
$hexchess = Hexchess:init();

$hexchess->getColor('b'); // [0,  1,  2,  ...]

isCheck ​

Test if the board is in check.

php
$hexchess = Hexchess::init();

$hexchess->isCheck(); // false

isCheckmate ​

Test if the game is in checkmate.

php
$hexchess = Hexchess::init();

$hexchess->isCheckmate(); // false

isLegal ​

Test if a move is legal.

php
$hexchess = Hexchess::init();

$hexchess->isLegal('b1b6'); // false

isStalemate ​

Test if the game is in stalemate.

php
$hexchess = Hexchess::init();

$hexchess->isStalemate(); // false

isThreatened ​

Test if a position is threatened by unsafe captures. This does not include forward pawn moves.

php
$hexchess = Hexchess::init();

$hexchess->isThreatened('f6'); // false

movesFrom ​

Get all legal moves from a position.

php
$hexchess = Hexchess:init();

$moves = $hexchess->movesFrom('f6');

array_map('strval', $moves); // ['f6f7']

movesFromUnsafe ​

Get all moves from a position, including ones that result in self-check.

php
$hexchess = Hexchess::parse('1/3/5/7/4r4/5K5/11/11/11/11/11 w - 0 1');

$moves = hexchess->movesUnsafe();

array_map('strval', $moves); // ['f6f7', 'f6g7' ...]

__toString ​

Serialize a Hexchess instance to string.

php
$hexchess = Hexchess::init();

$hexchess->__toString(); // 'b/qbk/n1b1n/r5r/ppppppppp/11/5P5/4P1P4/3P1B1P3/2P2B2P2/1PRNQBKNRP1 w - 0 1'