moveFromAlgebraic method

Move moveFromAlgebraic(String alg)

Create a Move from an algebraic string (e.g. a2a3, g6f3) for a board of this size.

Implementation

Move moveFromAlgebraic(String alg) {
  // A normal move - b1c3
  // A normal move with promo - e7e8q
  // A drop - e@g7
  // A gating move - g7f6/e
  // A disambiguated gating move - e1g1/eh1 (castling)
  if (alg[1] == '@') {
    // it's a drop
    int from = Squares.hand;
    int to = squareNumber(alg.substring(2));
    return Move(from: from, to: to, piece: alg[0]);
  }
  List<String> sections = alg.split('/');
  String move = sections.first;
  final m = _moveRegex.firstMatch(move);
  if (m == null) {
    throw Exception('Invalid move string: $alg');
  }
  int from = squareNumber(m.group(1)!);
  int to = squareNumber(m.group(2)!);
  String? promo = m.group(3);
  String? piece;
  int? gatingSquare;
  if (sections.length > 1) {
    String gate = sections.last;
    piece = gate[0];
    gatingSquare = gate.length > 2 ? squareNumber(gate.substring(1)) : from;
  }

  return Move(
    from: from,
    to: to,
    promo: promo,
    piece: piece,
    gatingSquare: gatingSquare,
  );
}