-
-
-/// move_to_san() takes a position and a legal Move as input and returns its
-/// short algebraic notation representation.
-
-const string move_to_san(Position& pos, Move m) {
-
- if (m == MOVE_NONE)
- return "(none)";
-
- if (m == MOVE_NULL)
- return "(null)";
-
- assert(pos.move_is_legal(m));
-
- Bitboard attackers;
- bool ambiguousMove, ambiguousFile, ambiguousRank;
- string san;
- Square from = from_sq(m);
- Square to = to_sq(m);
- PieceType pt = type_of(pos.piece_on(from));
-
- if (is_castle(m))
- san = to > from ? "O-O" : "O-O-O";
- else
- {
- if (pt != PAWN)
- {
- san = piece_type_to_char(pt);
-
- // Disambiguation if we have more then one piece with destination 'to'
- // note that for pawns is not needed because starting file is explicit.
- attackers = pos.attackers_to(to) & pos.pieces(pos.side_to_move(), pt);
- attackers ^= from;
- ambiguousMove = ambiguousFile = ambiguousRank = false;
-
- while (attackers)
- {
- Square sq = pop_1st_bit(&attackers);
-
- // Pinned pieces are not included in the possible sub-set
- if (!pos.pl_move_is_legal(make_move(sq, to), pos.pinned_pieces()))
- continue;
-
- ambiguousFile |= file_of(sq) == file_of(from);
- ambiguousRank |= rank_of(sq) == rank_of(from);
- ambiguousMove = true;
- }
-
- if (ambiguousMove)
- {
- if (!ambiguousFile)
- san += file_to_char(file_of(from));
-
- else if (!ambiguousRank)
- san += rank_to_char(rank_of(from));
-
- else
- san += square_to_string(from);
- }
- }
-
- if (pos.is_capture(m))
- {
- if (pt == PAWN)
- san += file_to_char(file_of(from));
-
- san += 'x';
- }
-
- san += square_to_string(to);
-
- if (is_promotion(m))
- san += string("=") + piece_type_to_char(promotion_type(m));
- }
-
- if (pos.move_gives_check(m, CheckInfo(pos)))
- {
- StateInfo st;
- pos.do_move(m, st);
- san += MoveList<MV_LEGAL>(pos).size() ? "+" : "#";
- pos.undo_move(m);
- }
-
- return san;
-}