How can I get all legal moves from a position?

[ghost]

Hi Jordi, I found this function to make legal moves, but it needs string $sq!

     public function legal(string $sq): ?object
     {
         if ($piece = $this->getPieceBySq($sq)) {
            $fen = [];
            foreach ($piece->sqs() as $sq) {
                if ($res = $piece->fen($piece->getColor(), $sq)) {
                    $fen[$sq] = $res;
                }
            }

            return (object) [
                'color' => $piece->getColor(),
                'id' => $piece->getId(),
                'fen' => (object) $fen,
            ];
         }

         return null;
     }

How can I get all legal moves from a position without $sq?

[programarivm]

Chess pieces can be looped through by using a foreach loop.

Also the space evaluation of the position may help. See Heuristics

[ghost]

@programarivm Could you please send me (random vs random) code?

[programarivm]

Sorry @EarlyEdition that I gave a wrong answer. This is how to obtain the legal moves from the start position.

$board = new Board();

$legal = [];

foreach ($board->getPieces() as $piece) {
    if ($sqs = $piece->sqs()) {
        $legal[$piece->getSq()] = $sqs;    
    }
}

print_r($legal);

Array
(
    [b1] => Array
        (
            [0] => a3
            [1] => c3
        )

    [g1] => Array
        (
            [0] => f3
            [1] => h3
        )

    [a2] => Array
        (
            [0] => a3
            [1] => a4
        )

    [b2] => Array
        (
            [0] => b3
            [1] => b4
        )

    [c2] => Array
        (
            [0] => c3
            [1] => c4
        )

    [d2] => Array
        (
            [0] => d3
            [1] => d4
        )

    [e2] => Array
        (
            [0] => e3
            [1] => e4
        )

    [f2] => Array
        (
            [0] => f3
            [1] => f4
        )

    [g2] => Array
        (
            [0] => g3
            [1] => g4
        )

    [h2] => Array
        (
            [0] => h3
            [1] => h4
        )

    [b8] => Array
        (
            [0] => a6
            [1] => c6
        )

    [g8] => Array
        (
            [0] => f6
            [1] => h6
        )

    [a7] => Array
        (
            [0] => a6
            [1] => a5
        )

    [b7] => Array
        (
            [0] => b6
            [1] => b5
        )

    [c7] => Array
        (
            [0] => c6
            [1] => c5
        )

    [d7] => Array
        (
            [0] => d6
            [1] => d5
        )

    [e7] => Array
        (
            [0] => e6
            [1] => e5
        )

    [f7] => Array
        (
            [0] => f6
            [1] => f5
        )

    [g7] => Array
        (
            [0] => g6
            [1] => g5
        )

    [h7] => Array
        (
            [0] => h6
            [1] => h5
        )

)

[programarivm]

The pieces can also be obtained by color or turn if you like as described next.

$board = new Board();

$legal = [];

foreach ($board->getPieces($board->getTurn()) as $piece) {
    if ($sqs = $piece->sqs()) {
        $legal[$piece->getSq()] = $sqs;
    }
}

print_r($legal);

Array
(
    [b1] => Array
        (
            [0] => a3
            [1] => c3
        )

    [g1] => Array
        (
            [0] => f3
            [1] => h3
        )

    [a2] => Array
        (
            [0] => a3
            [1] => a4
        )

    [b2] => Array
        (
            [0] => b3
            [1] => b4
        )

    [c2] => Array
        (
            [0] => c3
            [1] => c4
        )

    [d2] => Array
        (
            [0] => d3
            [1] => d4
        )

    [e2] => Array
        (
            [0] => e3
            [1] => e4
        )

    [f2] => Array
        (
            [0] => f3
            [1] => f4
        )

    [g2] => Array
        (
            [0] => g3
            [1] => g4
        )

    [h2] => Array
        (
            [0] => h3
            [1] => h4
        )

)