New issue on capture with SAN format

[andrescavallin]

Hello!!!

I think there is still a bug when capturing pawns using SAN format.
So this happened on a real game played with the DGT Board. I tested also with this code on latest chessops (v.0.7.2)
Here is a sample code to reproduce the issue:

Basically on the position on the sample, when the move "bxc6" is played, it returns an undefined object.
If the same move is played using UCI then it works fine.

// https://lichess.org/editor/r4br1/pp1Npkp1/2P4p/5P2/6P1/5KnP/PP6/R1B5_b_-_-_0_1
import { parseFen } from 'chessops/fen';
import { Chess } from 'chessops/chess';
import { board } from 'chessops/debug';
import { NormalMove, parseUci } from 'chessops';
import { parseSan } from 'chessops/san';

const setup = parseFen('r4br1/pp1Npkp1/2P4p/5P2/6P1/5KnP/PP6/R1B5 b - - 0 1').unwrap();
const localBoard = Chess.fromSetup(setup).unwrap();
console.log(board(localBoard.board));
var nextMove = 'bxc6';
//var nextMove = 'b6';
var moveObject: NormalMove | undefined;
moveObject = <NormalMove>parseSan(localBoard, nextMove);

if (moveObject !== undefined) {
    //This never happens
    console.log('moveObj looks good');
}
else {
    //Now try the uci version
    console.log('moveObj is undefined');
    console.log('bxc6 was invalid lets try with b7c6 \n')
    moveObject = <NormalMove>parseUci('b7c6');    
}

localBoard.play(moveObject);
console.log(board(localBoard.board));

Output

r . . . . b r .
p p . N p k p .
. . P . . . . p
. . . . . P . .
. . . . . . P .
. . . . . K n P
P P . . . . . .
R . B . . . . .

moveObj is undefined
bxc6 was invalid lets try with b7c6

r . . . . b r .
p . . N p k p .
. . p . . . . p
. . . . . P . .
. . . . . . P .
. . . . . K n P
P P . . . . . .
R . B . . . . .

[andrescavallin]

If nextMove value is set to "b6" then moveObjt looks good and works fine. So I think is something with the capture.

[niklasf]

Thanks. You can probably tell you're the first to extensively use this part of the library, so these reports are very valuable.

For bxc6, the parser was looking for a bishop 🤦. Fixed by requiring uppercase letters for pieces, e.g., Bxc6 if it really is intended to be a bishop move.

Published in v0.7.3.

[andrescavallin]

No problem my friend, thanks for all your great effort and for fixing this.