Add move generation for bishops and queens as well as attack tracking
This commit is contained in:
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82cef11cc4
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19ad46bbda
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@ -149,6 +149,8 @@ func shortCastleKing(color: PieceColor): Square {.inline.} = (if color == White:
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func longCastleRook(color: PieceColor): Square {.inline.} = (if color == White: makeSquare(7, 3) else: makeSquare(7, 5))
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func shortCastleRook(color: PieceColor): Square {.inline.} = (if color == White: makeSquare(0, 0) else: makeSquare(0, 2))
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proc inCheck(self: ChessBoard, side: PieceColor): bool
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proc newChessboard: ChessBoard =
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## Returns a new, empty chessboard
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@ -358,10 +360,9 @@ proc newChessboardFromFEN*(fen: string): ChessBoard =
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else:
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raise newException(ValueError, "invalid FEN: too many fields in FEN string")
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inc(index)
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# result.updateAttackedSquares()
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#[if result.inCheck(result.getSideToMove().opposite):
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if result.inCheck(result.getSideToMove().opposite):
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# Opponent king cannot be captured on the next move
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raise newException(ValueError, "invalid position: opponent king can be captured")]#
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raise newException(ValueError, "invalid position: opponent king can be captured")
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if result.position.pieces.white.king == 0 or result.position.pieces.black.king == 0:
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# Both kings must be on the board
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raise newException(ValueError, "invalid position: exactly one king of each color must be present")
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@ -548,7 +549,7 @@ proc getKingAttacks(self: ChessBoard, square: Square, attacker: PieceColor): Bit
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let
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sq = square.toBitboard()
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king = self.getBitboard(King, attacker)
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if (sq and KING_BITBOARDS[square.uint64]) != 0:
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if (KING_BITBOARDS[square.uint] and king) != 0:
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result = result or sq
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@ -560,10 +561,37 @@ proc getKnightAttacks(self: ChessBoard, square: Square, attacker: PieceColor): B
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knights = self.getBitboard(Knight, attacker)
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result = Bitboard(0)
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for knight in knights:
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if (sq and KNIGHT_BITBOARDS[knight.uint64]) != 0:
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if (KNIGHT_BITBOARDS[square.uint] and knight.toBitboard()) != 0:
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result = result or knight.toBitboard()
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proc getSlidingAttacks(self: ChessBoard, square: Square, attacker: PieceColor): Bitboard =
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## Returns the attack bitboard for the given square from
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## the sliding pieces of the given side
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let
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sq = square.toBitboard()
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queens = self.getBitboard(Queen, attacker)
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rooks = self.getBitboard(Rook, attacker)
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bishops = self.getBitboard(Bishop, attacker)
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occupancy = self.getOccupancy()
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result = Bitboard(0)
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for rook in rooks:
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let blockers = Rook.getRelevantBlockers(square)
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if (getRookMoves(square, blockers) and rook.toBitboard()) != 0:
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result = result or rook.toBitboard()
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for bishop in bishops:
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let blockers = Bishop.getRelevantBlockers(square)
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if (getBishopMoves(square, blockers) and bishop.toBitboard()) != 0:
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result = result or bishop.toBitboard()
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for queen in queens:
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let rookBlockers = Rook.getRelevantBlockers(square)
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if (getRookMoves(square, rookBlockers) and queen.toBitboard()) != 0:
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result = result or queen.toBitboard()
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let bishopBlockers = Bishop.getRelevantBlockers(square)
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if (getBishopMoves(square, bishopBlockers) and queen.toBitboard()) != 0:
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result = result or queen.toBitboard()
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proc getAttacksTo(self: ChessBoard, square: Square, attacker: PieceColor): Bitboard =
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## Computes the attack bitboard for the given square from
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## the given side
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@ -573,6 +601,17 @@ proc getAttacksTo(self: ChessBoard, square: Square, attacker: PieceColor): Bitbo
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result = result or self.getPawnAttacks(square, attacker)
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result = result or self.getKingAttacks(square, attacker)
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result = result or self.getKnightAttacks(square, attacker)
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result = result or self.getSlidingAttacks(square, attacker)
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proc inCheck(self: ChessBoard, side: PieceColor): bool =
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## Returns if the current side to move is in check
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return self.getAttacksTo(self.getKingSquare(side), side.opposite()) != 0
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proc canCastle(self: ChessBoard, side: PieceColor): tuple[king, queen: bool] =
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## Returns if the current side to move can castle
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return (false, false) # TODO
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proc getCapturablePieces(self: ChessBoard, side: PieceColor): Bitboard {.inline.} =
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@ -597,7 +636,7 @@ proc generatePawnMovements(self: ChessBoard, moves: var MoveList) =
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for square in pawns.forwardRelativeTo(sideToMove) and allowedSquares:
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moves.add(createMove(square.toBitboard().backwardRelativeTo(sideToMove), square))
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# Double push
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let rank = if sideToMove == White: getRankMask(6) else: getRankMask(1) # Only pawns on their starting rank can double push
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let rank = sideToMove.getFirstRank() # Only pawns on their starting rank can double push
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for square in (pawns and rank).doubleForwardRelativeTo(sideToMove) and allowedSquares:
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moves.add(createMove(square.toBitboard().doubleBackwardRelativeTo(sideToMove), square, DoublePush))
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@ -661,7 +700,7 @@ proc generateRookMovements(self: ChessBoard, moves: var MoveList) =
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for square in rooks:
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let blockers = occupancy and Rook.getRelevantBlockers(square)
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var moveset = getRookMoves(square, blockers)
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# Can't capture our own pieces
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# Can't move over our own pieces
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moveset = moveset and not friendlyPieces
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for target in moveset:
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moves.add(createMove(square, target))
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@ -679,9 +718,10 @@ proc generateRookCaptures(self: ChessBoard, moves: var MoveList) =
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let blockers = occupancy and Rook.getRelevantBlockers(square)
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var moveset = getRookMoves(square, blockers)
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# Can only cature enemy pieces
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moveset = moveset and not enemyPieces
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moveset = moveset and enemyPieces
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for target in moveset:
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moves.add(createMove(square, target))
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moves.add(createMove(square, target, Capture))
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proc generateRookMoves(self: ChessBoard, moves: var MoveList) =
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## Helper of generateSlidingMoves to generate rook moves
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@ -689,9 +729,103 @@ proc generateRookMoves(self: ChessBoard, moves: var MoveList) =
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self.generateRookCaptures(moves)
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proc generateBishopMovements(self: ChessBoard, moves: var MoveList) =
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## Helper of generateBishopMoves to generate all non-capture
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## bishop moves
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let
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sideToMove = self.getSideToMove()
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occupancy = self.getOccupancy()
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friendlyPieces = self.getOccupancyFor(sideToMove)
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bishops = self.getBitboard(Bishop, sideToMove)
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for square in bishops:
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let blockers = occupancy and Bishop.getRelevantBlockers(square)
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var moveset = getBishopMoves(square, blockers)
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# Can't move over our own pieces
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moveset = moveset and not friendlyPieces
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for target in moveset:
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moves.add(createMove(square, target))
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proc generateBishopCaptures(self: ChessBoard, moves: var MoveList) =
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## Helper of generateBishopMoves to generate all capture
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## bishop moves
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let
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sideToMove = self.getSideToMove()
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occupancy = self.getOccupancy()
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enemyPieces = self.getCapturablePieces(sideToMove.opposite())
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bishops = self.getBitboard(Bishop, sideToMove)
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for square in bishops:
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let blockers = occupancy and Bishop.getRelevantBlockers(square)
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var moveset = getRookMoves(square, blockers)
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# Can only cature enemy pieces
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moveset = moveset and enemyPieces
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for target in moveset:
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moves.add(createMove(square, target, Capture))
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proc generateBishopMoves(self: ChessBoard, moves: var MoveList) =
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## Helper of generateSlidingMoves to generate bishop moves
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self.generateBishopMovements(moves)
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self.generateBishopCaptures(moves)
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proc generateQueenMovements(self: ChessBoard, moves: var MoveList) =
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## Helper of generateQueenMoves to generate all non-capture
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## bishop moves
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let
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sideToMove = self.getSideToMove()
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occupancy = self.getOccupancy()
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friendlyPieces = self.getOccupancyFor(sideToMove)
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queens = self.getBitboard(Queen, sideToMove)
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for square in queens:
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# A queen is just a rook plus a bishop in terms of move
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# generation
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let
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rookBlockers = Rook.getRelevantBlockers(square) and occupancy
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bishopBlockers = Bishop.getRelevantBlockers(square) and occupancy
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rookMoves = getRookMoves(square, rookBlockers)
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bishopMoves = getBishopMoves(square, bishopBlockers)
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var moveset = rookMoves or bishopMoves
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# Can't move over our own pieces
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moveset = moveset and not friendlyPieces
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for target in moveset:
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moves.add(createMove(square, target))
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proc generateQueenCaptures(self: ChessBoard, moves: var MoveList) =
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## Helper of generateQueenMoves to generate all capture
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## queen moves
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let
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sideToMove = self.getSideToMove()
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occupancy = self.getOccupancy()
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enemyPieces = self.getCapturablePieces(sideToMove.opposite())
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queens = self.getBitboard(Queen, sideToMove)
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for square in queens:
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# A queen is just a rook plus a bishop in terms of move
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# generation
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let
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rookBlockers = Rook.getRelevantBlockers(square) and occupancy
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bishopBlockers = Bishop.getRelevantBlockers(square) and occupancy
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rookMoves = getRookMoves(square, rookBlockers)
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bishopMoves = getBishopMoves(square, bishopBlockers)
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var moveset = rookMoves or bishopMoves
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# Can only capture the enemy pieces
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moveset = moveset and enemyPieces
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for target in moveset:
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moves.add(createMove(square, target, Capture))
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proc generateQueenMoves(self: ChessBoard, moves: var MoveList) =
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## Helper of generateSlidingMoves to generate queen moves
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self.generateQueenMovements(moves)
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self.generateQueenCaptures(moves)
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proc generateSlidingMoves(self: ChessBoard, moves: var MoveList) =
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## Generates all legal sliding moves for the side to move
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self.generateRookMoves(moves)
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self.generateBishopMoves(moves)
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self.generateQueenMoves(moves)
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proc generateKingMoves(self: ChessBoard, moves: var MoveList) =
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@ -800,8 +934,7 @@ proc generateMoves*(self: ChessBoard, moves: var MoveList) =
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self.generatePawnMoves(moves)
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self.generateKingMoves(moves)
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self.generateKnightMoves(moves)
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self.generateRookMoves(moves)
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# TODO: all pieces
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self.generateSlidingMoves(moves)
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proc removePieceFromBitboard(self: ChessBoard, square: Square) =
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@ -1329,7 +1462,7 @@ proc toFEN*(self: ChessBoard): string =
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# Fullmove number
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result &= $self.getMoveCount()
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#[
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proc perft*(self: ChessBoard, ply: int, verbose: bool = false, divide: bool = false, bulk: bool = false): CountData =
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## Counts (and debugs) the number of legal positions reached after
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## the given number of ply
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@ -1337,7 +1470,7 @@ proc perft*(self: ChessBoard, ply: int, verbose: bool = false, divide: bool = fa
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var moves = MoveList()
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self.generateMoves(moves)
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if not bulk:
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if len(moves) == 0 and self.inCheck():
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if len(moves) == 0 and self.inCheck(self.getSideToMove()):
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result.checkmates = 1
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# TODO: Should we count stalemates/draws?
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if ply == 0:
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@ -1367,11 +1500,11 @@ proc perft*(self: ChessBoard, ply: int, verbose: bool = false, divide: bool = fa
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if verbose:
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let canCastle = self.canCastle(self.getSideToMove())
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echo &"Ply (from root): {self.position.plyFromRoot}"
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echo &"Move: {move.startSquare.toAlgebraic()}{move.targetSquare.toAlgebraic()}, from ({move.startSquare.rank}, {move.startSquare.file}) to ({move.targetSquare.rank}, {move.targetSquare.file})"
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echo &"Move: {move.startSquare.toAlgebraic()}{move.targetSquare.toAlgebraic()}"
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echo &"Turn: {self.getSideToMove()}"
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echo &"Piece: {self.grid[move.startSquare].kind}"
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echo &"Flags: {move.getFlags()}"
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echo &"In check: {(if self.inCheck(): \"yes\" else: \"no\")}"
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echo &"In check: {(if self.inCheck(self.getSideToMove()): \"yes\" else: \"no\")}"
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echo &"Can castle:\n - King side: {(if canCastle.king: \"yes\" else: \"no\")}\n - Queen side: {(if canCastle.queen: \"yes\" else: \"no\")}"
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echo &"Position before move: {self.toFEN()}"
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stdout.write("En Passant target: ")
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@ -1390,13 +1523,13 @@ proc perft*(self: ChessBoard, ply: int, verbose: bool = false, divide: bool = fa
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inc(result.promotions)
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if move.isEnPassant():
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inc(result.enPassant)
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if self.inCheck():
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if self.inCheck(self.getSideToMove()):
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# Opponent king is in check
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inc(result.checks)
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if verbose:
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let canCastle = self.canCastle(self.getSideToMove())
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echo "\n"
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echo &"Opponent in check: {(if self.inCheck(): \"yes\" else: \"no\")}"
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echo &"Opponent in check: {(if self.inCheck(self.getSideToMove()): \"yes\" else: \"no\")}"
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echo &"Opponent can castle:\n - King side: {(if canCastle.king: \"yes\" else: \"no\")}\n - Queen side: {(if canCastle.queen: \"yes\" else: \"no\")}"
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echo &"Position after move: {self.toFEN()}"
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echo "\n", self.pretty()
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@ -1433,7 +1566,7 @@ proc perft*(self: ChessBoard, ply: int, verbose: bool = false, divide: bool = fa
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result.castles += next.castles
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result.enPassant += next.enPassant
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result.checkmates += next.checkmates
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]#
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proc handleGoCommand(board: ChessBoard, command: seq[string]) =
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if len(command) < 2:
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@ -1462,7 +1595,7 @@ proc handleGoCommand(board: ChessBoard, command: seq[string]) =
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break
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if not ok:
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return
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#[try:
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try:
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let ply = parseInt(args[0])
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if bulk:
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let t = cpuTime()
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@ -1485,7 +1618,6 @@ proc handleGoCommand(board: ChessBoard, command: seq[string]) =
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echo "Error: go: perft: invalid depth"
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else:
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echo &"Error: go: unknown subcommand '{command[1]}'"
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]#
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proc handleMoveCommand(board: ChessBoard, command: seq[string]): Move {.discardable.} =
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@ -1660,6 +1792,7 @@ const HELP_TEXT = """Nimfish help menu:
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- fen: Shorthand for "position fen"
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- pos <args>: Shorthand for "position <args>"
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- get <square>: Get the piece on the given square
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- atk: Print the attack bitboard of the given square for the side to move
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- uci: enter UCI mode (WIP)
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"""
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@ -1703,6 +1836,15 @@ proc main: int =
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board.unmakeMove()
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of "turn":
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echo &"Active color: {board.getSideToMove()}"
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of "atk":
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if len(cmd) != 2:
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echo "error: atk: invalid number of arguments"
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continue
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try:
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echo board.getAttacksTo(cmd[1].toSquare(), board.getSideToMove())
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except ValueError:
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echo "error: atk: invalid square"
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continue
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of "ep":
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let target = board.getEnPassantTarget()
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if target != nullSquare():
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@ -1718,12 +1860,11 @@ proc main: int =
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except ValueError:
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echo "error: get: invalid square"
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continue
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#[of "castle":
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let canCastle = board.canCastle()
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of "castle":
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let canCastle = board.canCastle(board.getSideToMove())
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echo &"Castling rights for {($board.getSideToMove()).toLowerAscii()}:\n - King side: {(if canCastle.king: \"yes\" else: \"no\")}\n - Queen side: {(if canCastle.queen: \"yes\" else: \"no\")}"
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of "check":
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echo &"{board.getSideToMove()} king in check: {(if board.inCheck(): \"yes\" else: \"no\")}"
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]#
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echo &"{board.getSideToMove()} king in check: {(if board.inCheck(board.getSideToMove()): \"yes\" else: \"no\")}"
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else:
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echo &"Unknown command '{cmd[0]}'. Type 'help' for more information."
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except IOError:
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@ -1839,14 +1980,5 @@ when isMainModule:
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testPieceBitboard(blackQueens, blackQueenSquares)
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testPieceBitboard(blackKing, blackKingSquares)
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b = newChessboardFromFEN("8/5R2/8/8/7k/8/5K2/8 w - - 0 1")
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var m = MoveList()
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b.generateRookMovements(m)
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echo &"There are {len(m)} legal moves for {b.getSideToMove()} at {b.toFEN()}: "
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for move in m:
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echo " - ", move.startSquare, move.targetSquare, " ", move.getFlags()
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echo b.pretty()
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# setControlCHook(proc () {.noconv.} = quit(0))
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# quit(main())
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setControlCHook(proc () {.noconv.} = quit(0))
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quit(main())
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@ -342,9 +342,10 @@ else:
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var path = joinPath(getCurrentDir(), "src/resources")
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if path.lastPathPart() == "nimfish":
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path = joinPath("src", path)
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echo "Loading magic bitboards"
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var magics = readFile(joinPath(path, "magics.json")).fromJson(TableRef[string, array[64, MagicEntry]])
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var moves = readFile(joinPath(path, "movesets.json")).fromJson(TableRef[string, array[64, seq[Bitboard]]])
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ROOK_MAGICS = magics["rooks"]
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BISHOP_MAGICS = magics["bishops"]
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ROOK_MOVES = moves["rooks"]
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BISHOP_MOVES = moves["bishops"]
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BISHOP_MOVES = moves["bishops"]
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