Fixes to generation and added basic debugger
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60c4f28ec0
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@ -17,6 +17,7 @@ export matrix
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import std/strutils
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import std/strformat
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import std/sequtils
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type
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@ -50,12 +51,16 @@ type
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MoveFlag* = enum
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## An enumeration of move flags
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Default = 0'i8, # Move is a regular move
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# Castling
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Default = 0'i8, # No flag
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Capture, # Move is a capture
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EnPassant, # Move is an en passant
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Backwards, # Move is a backward move generated by undoMove
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DoublePush, # Move is a double pawn push
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# Castling metadata
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CastleLong,
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CastleShort,
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XRay, # Move is an X-ray attack
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# Move is a pawn promotion
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# Pawn promotion metadata
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PromoteToQueen,
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PromoteToRook,
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PromoteToBishop,
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@ -125,9 +130,12 @@ func `+`*(a, b: Location): Location = (a.row + b.row, a.col + b.col)
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func isValid*(a: Location): bool {.inline.} = a.row in 0..7 and a.col in 0..7
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proc generateMoves(self: ChessBoard, location: Location): seq[Move]
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proc isAttacked*(self: ChessBoard, loc: Location): bool
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proc undoLastMove*(self: ChessBoard): Move {.discardable.}
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proc isLegal(self: ChessBoard, move: Move): bool
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proc undoMove*(self: ChessBoard, move: Move): Move {.discardable.}
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proc isLegal(self: ChessBoard, move: Move, keep: bool = false): bool
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proc doMove(self: ChessBoard, move: Move)
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proc isLegalFast(self: ChessBoard, move: Move, keep: bool = false): bool
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proc makeMoveFast*(self: ChessBoard, move: Move): Move {.discardable.}
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proc pretty*(self: ChessBoard): string
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# Due to our board layout, directions of movement are reversed for white/black so
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# we need these helpers to avoid going mad with integer tuples and minus signs
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@ -142,10 +150,10 @@ func topSide(color: PieceColor): Location {.inline.} = (if color == White: (-1,
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func bottomSide(color: PieceColor): Location {.inline.} = (if color == White: (1, 0) else: (-1, 0))
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func forward(color: PieceColor): Location {.inline.} = (if color == White: (-1, 0) else: (1, 0))
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func doublePush(color: PieceColor): Location {.inline.} = (if color == White: (-2, 0) else: (2, 0))
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func longCastleKing(color: PieceColor): Location {.inline.} = (0, -2)
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func shortCastleKing(color: PieceColor): Location {.inline.} = (0, 2)
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func longCastleRook(color: PieceColor): Location {.inline.} = (0, 3)
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func shortCastleRook(color: PieceColor): Location {.inline.} = (0, -2)
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func longCastleKing: Location {.inline.} = (0, -2)
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func shortCastleKing: Location {.inline.} = (0, 2)
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func longCastleRook: Location {.inline.} = (0, 3)
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func shortCastleRook: Location {.inline.} = (0, -2)
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func kingSideRook(color: PieceColor): Location {.inline.} = (if color == White: (7, 7) else: (0, 7))
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func queenSideRook(color: PieceColor): Location {.inline.} = (if color == White: (7, 0) else: (0, 0))
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@ -155,25 +163,25 @@ func bottomLeftKnightMove(color: PieceColor, long: bool = true): Location {.inli
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if long:
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return (2, -1)
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else:
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return (-1, -2)
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return (1, -2)
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elif color == Black:
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if long:
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return (-2, 1)
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return (2, 1)
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else:
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return (1, -2)
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return (2, -1)
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func bottomRightKnightMove(color: PieceColor, long: bool = true): Location {.inline.} =
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if color == White:
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if long:
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return (2, -1)
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return (2, 1)
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else:
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return (1, 2)
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elif color == Black:
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if long:
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return (2, 1)
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return (-2, -1)
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else:
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return (1, 2)
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return (-1, -2)
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func topLeftKnightMove(color: PieceColor, long: bool = true): Location {.inline.} =
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@ -199,7 +207,7 @@ func topRightKnightMove(color: PieceColor, long: bool = true): Location {.inline
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if long:
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return (2, -1)
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else:
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return (-1, 2)
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return (1, -2)
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func getActiveColor*(self: ChessBoard): PieceColor {.inline.} =
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@ -266,7 +274,8 @@ proc newChessboard: ChessBoard =
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result.position = Position(attacked: (@[], @[]),
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enPassantSquare: emptyMove(),
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move: emptyMove(),
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turn: White)
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turn: White,
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fullMoveCount: 1)
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@ -347,8 +356,8 @@ proc newChessboardFromFEN*(state: string): ChessBoard =
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column = 0
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of '0'..'9':
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# Skip x columns
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let x = int(uint8(c) - uint8('0')) - 1
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if x > 7:
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let x = int(uint8(c) - uint8('0'))
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if x > 8:
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raise newException(ValueError, "invalid skip value (> 8) in FEN string")
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column += int8(x)
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else:
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@ -530,7 +539,7 @@ func getCapture*(self: ChessBoard, move: Move): Location =
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return
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else:
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return ((if move.piece.color == White: move.targetSquare.row + 1 else: move.targetSquare.row - 1), move.targetSquare.col)
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if target.color == move.piece.color.opposite():
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elif target.color == move.piece.color.opposite():
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return move.targetSquare
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@ -545,20 +554,17 @@ proc inCheck*(self: ChessBoard, color: PieceColor = None): bool =
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## king is in check. If the color is
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## set to None, checks are checked
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## for the active color's king
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var color = color
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if color == None:
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color = self.getActiveColor()
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case color:
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of White:
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return self.isAttacked(self.position.pieces.white.king)
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of Black:
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return self.isAttacked(self.position.pieces.black.king)
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of None:
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case self.getActiveColor():
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of White:
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return self.isAttacked(self.position.pieces.white.king)
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of Black:
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return self.isAttacked(self.position.pieces.black.king)
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else:
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# Unreachable
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discard
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else:
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# Unreachable
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discard
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proc canCastle*(self: ChessBoard, color: PieceColor = None): tuple[queen, king: bool] {.inline.} =
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@ -647,57 +653,51 @@ proc generatePawnMoves(self: ChessBoard, location: Location): seq[Move] =
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var
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piece = self.grid[location.row, location.col]
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locations: seq[Location] = @[]
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flags: seq[MoveFlag] = @[]
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doAssert piece.kind == Pawn, &"generatePawnMoves called on a {piece.kind}"
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# Pawns can move forward one square
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let forwardOffset = piece.color.forward()
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let forward = (forwardOffset + location)
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# Only if the square is empty though
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if forward.isValid() and self.grid[forward.row, forward.col].color == None:
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locations.add(forwardOffset)
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flags.add(Default)
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# If the pawn is on its first rank, it can push two squares
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if location.row == piece.getStartRow():
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locations.add(piece.color.doublePush())
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let doubleOffset = piece.color.doublePush()
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let double = location + doubleOffset
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# Check if both squares are available
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if double.isValid() and self.grid[forward.row, forward.col].color == None and self.grid[double.row, double.col].color == None:
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locations.add(piece.color.doublePush())
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flags.add(DoublePush)
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if self.position.enPassantSquare.piece.color == piece.color.opposite:
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if abs(self.position.enPassantSquare.targetSquare.col - location.col) == 1 and abs(self.position.enPassantSquare.targetSquare.row - location.row) == 1:
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# Only viable if the piece is on the diagonal of the target
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locations.add(self.position.enPassantSquare.targetSquare)
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flags.add(EnPassant)
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# They can also move on either diagonal one
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# square, but only to capture
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if location.col in 1..6:
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# Top right diagonal
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locations.add(piece.color.topRightDiagonal())
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if location.row in 1..6:
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# Top left diagonal
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locations.add(piece.color.topLeftDiagonal())
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# Pawn is at the right side, can only capture
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# on the left one
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if location.col == 7 and location.row < 7:
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locations.add(piece.color.topLeftDiagonal())
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# Pawn is at the left side, can only capture
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# on the right one
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if location.col == 0 and location.row < 7:
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locations.add(piece.color.topRightDiagonal())
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var diagonal = piece.color.topRightDiagonal()
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if (diagonal + location).isValid() and self.isCapture(Move(piece: piece, startSquare: location, targetSquare: location + diagonal)):
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locations.add(diagonal)
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flags.add(Capture)
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diagonal = piece.color.topLeftDiagonal()
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if (diagonal + location).isValid() and self.isCapture(Move(piece: piece, startSquare: location, targetSquare: location + diagonal)):
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locations.add(diagonal)
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flags.add(Capture)
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var
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newLocation: Location
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targetPiece: Piece
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for target in locations:
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for (target, flag) in zip(locations, flags):
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newLocation = location + target
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if not newLocation.isValid():
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continue
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targetPiece = self.grid[newLocation.row, newLocation.col]
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if targetPiece.color == piece.color:
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# Can't move over a friendly piece
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continue
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if location.col != newLocation.col and not self.isCapture(Move(piece: piece, startSquare: location, targetSquare: newLocation)):
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# Can only move diagonally when capturing
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continue
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if newLocation.row == piece.color.getLastRow():
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# Generate all promotion moves
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# Pawn reached the other side of the board: generate all potential piece promotions
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for promotionType in [PromoteToKnight, PromoteToBishop, PromoteToRook, PromoteToQueen]:
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result.add(Move(startSquare: location, targetSquare: newLocation, piece: piece, flag: promotionType))
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continue
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# Move is just a pawn push
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result.add(Move(startSquare: location, targetSquare: newLocation, piece: piece))
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result.add(Move(startSquare: location, targetSquare: newLocation, piece: piece, flag: flag))
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proc generateSlidingMoves(self: ChessBoard, location: Location): seq[Move] =
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@ -734,7 +734,7 @@ proc generateSlidingMoves(self: ChessBoard, location: Location): seq[Move] =
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if otherPiece.color == piece.color.opposite:
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# Target square contains an enemy piece: capture
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# it and stop going any further
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result.add(Move(startSquare: location, targetSquare: square, piece: piece))
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result.add(Move(startSquare: location, targetSquare: square, piece: piece, flag: Capture))
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break
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# Target square is empty
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result.add(Move(startSquare: location, targetSquare: square, piece: piece))
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@ -756,21 +756,25 @@ proc generateKingMoves(self: ChessBoard, location: Location): seq[Move] =
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# Castling
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let canCastle = self.canCastle()
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if canCastle.queen:
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directions.add(piece.color.longCastleKing())
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directions.add(longCastleKing())
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if canCastle.king:
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directions.add(piece.color.shortCastleKing())
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directions.add(shortCastleKing())
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var flag = Default
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for direction in directions:
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if direction == piece.color.longCastleKing():
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if direction == longCastleKing():
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flag = CastleLong
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elif direction == piece.color.shortCastleKing():
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elif direction == shortCastleKing():
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flag = CastleShort
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else:
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flag = Default
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# Step in this direction once
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let square: Location = location + direction
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# End of board reached
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if not square.isValid():
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continue
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let otherPiece = self.grid[square.row, square.col]
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if otherPiece.color == self.getActiveColor.opposite():
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flag = Capture
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# A friendly piece is in the way, move onto the next
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# direction
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if otherPiece.color == piece.color:
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@ -806,7 +810,7 @@ proc generateKnightMoves(self: ChessBoard, location: Location): seq[Move] =
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if otherPiece.color == piece.color.opposite:
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# Target square contains an enemy piece: capture
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# it
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result.add(Move(startSquare: location, targetSquare: square, piece: piece))
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result.add(Move(startSquare: location, targetSquare: square, piece: piece, flag: Capture))
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continue
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# Target square is empty
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result.add(Move(startSquare: location, targetSquare: square, piece: piece))
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@ -829,14 +833,6 @@ proc generateMoves(self: ChessBoard, location: Location): seq[Move] =
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return @[]
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proc generateLegalMoves*(self: ChessBoard, location: Location): seq[Move] =
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## Returns the list of possible legal chess moves for the
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## piece in the given location
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for move in self.generateMoves(location):
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if self.isLegal(move):
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result.add(move)
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proc generateAllMoves*(self: ChessBoard): seq[Move] =
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## Returns the list of all possible pseudo-legal moves
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## in the current position
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@ -848,18 +844,6 @@ proc generateAllMoves*(self: ChessBoard): seq[Move] =
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result.add(move)
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proc countLegalMoves*(self: ChessBoard, ply: int): int =
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## Counts the number of legal positions reached after
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## the given number of half moves
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if ply == 0:
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return 1
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for move in self.generateAllMoves():
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if self.isLegal(move):
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#echo &"{move.piece.color} {move.piece.kind} {move.startSquare.locationToAlgebraic()} {move.targetSquare.locationtoAlgebraic()}"
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result += self.countLegalMoves(ply - 1)
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proc getAttackers*(self: ChessBoard, square: Location): seq[Piece] =
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## Returns all the attackers of the given square
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for move in self.position.attacked.black:
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@ -910,12 +894,7 @@ proc updateAttackedSquares(self: ChessBoard) =
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## Updates internal metadata about which squares
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## are attacked. Called internally by doMove
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# We refresh the attack metadata at every move. This is an
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# O(1) operation, because we're only updating the length
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# field without deallocating the memory, which will promptly
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# be reused by us again. Neat!
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self.position.attacked.white.setLen(0)
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self.position.attacked.black.setLen(0)
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# Go over each piece one by one and see which squares
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# it currently attacks
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@ -988,7 +967,7 @@ proc removePiece(self: ChessBoard, location: Location) =
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of Black:
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case piece.kind:
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of Pawn:
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self.position.pieces.black.pawns.delete(self.position.pieces.white.pawns.find(location))
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self.position.pieces.black.pawns.delete(self.position.pieces.black.pawns.find(location))
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of Bishop:
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self.position.pieces.black.bishops.delete(self.position.pieces.black.bishops.find(location))
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of Knight:
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@ -1005,10 +984,11 @@ proc removePiece(self: ChessBoard, location: Location) =
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discard
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proc movePiece(self: ChessBoard, move: Move) =
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## Internal helper to move a piece. Does
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## not update attacked squares, just position
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## metadata and the grid itself
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proc movePiece(self: ChessBoard, move: Move, attack: bool = true) =
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## Internal helper to move a piece. If attack
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## is set to false, then this function does
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## not update attacked squares metadata, just
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## positional info and the grid itself
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case move.piece.color:
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of White:
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case move.piece.kind:
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@ -1059,21 +1039,30 @@ proc movePiece(self: ChessBoard, move: Move) =
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# Empty out the starting square
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self.grid[move.startSquare.row, move.startSquare.col] = emptyPiece()
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# Actually move the piece
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self.grid[move.targetSquare.row, move.targetSquare.col] = move.piece
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self.grid[move.targetSquare.row, move.targetSquare.col] = move.piece
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if attack:
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self.updateAttackedSquares()
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proc updatePositions(self: ChessBoard, move: Move) =
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proc movePiece(self: ChessBoard, startSquare, targetSquare: Location, attack: bool = true) =
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## Like the other movePiece(), but with two locations
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self.movePiece(Move(startSquare: startSquare, targetSquare: targetSquare,
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piece: self.grid[startSquare.row, startSquare.col],
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),
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attack
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)
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proc updateLocations(self: ChessBoard, move: Move) =
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## Internal helper to update the position of
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## the pieces on the board after a move
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let capture = self.getCapture(move)
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if capture != emptyLocation():
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self.position.captured = self.grid[capture.row, capture.col]
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if capture != self.getEnPassantTarget():
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# En passant is handled elsewhere
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self.removePiece(capture)
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self.removePiece(capture)
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# Update the positional metadata of the moving piece
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self.movePiece(move)
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proc doMove(self: ChessBoard, move: Move) =
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## Internal function called by makeMove after
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@ -1083,7 +1072,7 @@ proc doMove(self: ChessBoard, move: Move) =
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# Final checks
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# Record the move in the position
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# Record the final move in the position
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self.position.move = move
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# Needed to detect draw by the 50 move rule
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@ -1091,110 +1080,115 @@ proc doMove(self: ChessBoard, move: Move) =
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halfMoveClock = self.position.halfMoveClock
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fullMoveCount = self.position.fullMoveCount
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castlingAvailable = self.position.castlingAvailable
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if move.piece.kind == Pawn or self.isCapture(move):
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halfMoveClock = 0
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else:
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inc(halfMoveClock)
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if move.piece.color == Black:
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inc(fullMoveCount)
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# Castling check: have the rooks moved?
|
||||
if move.piece.kind == Rook:
|
||||
case move.piece.color:
|
||||
of White:
|
||||
if move.startSquare.row == move.piece.getStartRow():
|
||||
if move.startSquare.col == 0:
|
||||
# Queen side
|
||||
castlingAvailable.white.queen = false
|
||||
elif move.startSquare.col == 7:
|
||||
# King side
|
||||
castlingAvailable.white.king = false
|
||||
of Black:
|
||||
if move.startSquare.row == move.piece.getStartRow():
|
||||
if move.startSquare.col == 0:
|
||||
# Queen side
|
||||
castlingAvailable.black.queen = false
|
||||
elif move.startSquare.col == 7:
|
||||
# King side
|
||||
castlingAvailable.black.king = false
|
||||
else:
|
||||
discard
|
||||
# Has a rook been captured?
|
||||
let capture = self.getCapture(move)
|
||||
if capture != emptyLocation():
|
||||
let piece = self.grid[capture.row, capture.col]
|
||||
if piece.kind == Rook:
|
||||
case piece.color:
|
||||
of White:
|
||||
if capture == piece.color.queenSideRook():
|
||||
# Queen side
|
||||
castlingAvailable.white.queen = false
|
||||
elif capture == piece.color.kingSideRook():
|
||||
# King side
|
||||
castlingAvailable.white.king = false
|
||||
of Black:
|
||||
if capture == piece.color.queenSideRook():
|
||||
# Queen side
|
||||
castlingAvailable.black.queen = false
|
||||
elif capture == piece.color.kingSideRook():
|
||||
# King side
|
||||
castlingAvailable.black.king = false
|
||||
else:
|
||||
# Unreachable
|
||||
discard
|
||||
# Has the king moved?
|
||||
if move.piece.kind == King:
|
||||
case move.piece.color:
|
||||
of White:
|
||||
castlingAvailable.white.king = false
|
||||
castlingAvailable.white.queen = false
|
||||
of Black:
|
||||
castlingAvailable.black.king = false
|
||||
castlingAvailable.black.queen = false
|
||||
else:
|
||||
discard
|
||||
# Update position and attack metadata
|
||||
self.updatePositions(move)
|
||||
self.updateAttackedSquares()
|
||||
|
||||
var location: Location
|
||||
if move.flag in [CastleShort, CastleLong]:
|
||||
# Move the rook onto the
|
||||
# correct file
|
||||
var
|
||||
location: Location
|
||||
target: Location
|
||||
if move.flag == CastleShort:
|
||||
location = move.piece.color.kingSideRook()
|
||||
target = move.piece.color.shortCastleRook()
|
||||
if move.flag != Backwards:
|
||||
if move.piece.kind == Pawn or self.isCapture(move):
|
||||
halfMoveClock = 0
|
||||
else:
|
||||
location = move.piece.color.queenSideRook()
|
||||
target = move.piece.color.longCastleRook()
|
||||
let rook = self.grid[location.row, location.col]
|
||||
let move = Move(startSquare: location, targetSquare: location + target, piece: rook, flag: move.flag)
|
||||
self.updatePositions(move)
|
||||
self.updateAttackedSquares()
|
||||
inc(halfMoveClock)
|
||||
if move.piece.color == Black:
|
||||
inc(fullMoveCount)
|
||||
# Castling check: have the rooks moved?
|
||||
if move.piece.kind == Rook:
|
||||
case move.piece.color:
|
||||
of White:
|
||||
if move.startSquare.row == move.piece.getStartRow():
|
||||
if move.startSquare.col == 0:
|
||||
# Queen side
|
||||
castlingAvailable.white.queen = false
|
||||
elif move.startSquare.col == 7:
|
||||
# King side
|
||||
castlingAvailable.white.king = false
|
||||
of Black:
|
||||
if move.startSquare.row == move.piece.getStartRow():
|
||||
if move.startSquare.col == 0:
|
||||
# Queen side
|
||||
castlingAvailable.black.queen = false
|
||||
elif move.startSquare.col == 7:
|
||||
# King side
|
||||
castlingAvailable.black.king = false
|
||||
else:
|
||||
discard
|
||||
# Has a rook been captured?
|
||||
let capture = self.getCapture(move)
|
||||
if capture != emptyLocation():
|
||||
let piece = self.grid[capture.row, capture.col]
|
||||
if piece.kind == Rook:
|
||||
case piece.color:
|
||||
of White:
|
||||
if capture == piece.color.queenSideRook():
|
||||
# Queen side
|
||||
castlingAvailable.white.queen = false
|
||||
elif capture == piece.color.kingSideRook():
|
||||
# King side
|
||||
castlingAvailable.white.king = false
|
||||
of Black:
|
||||
if capture == piece.color.queenSideRook():
|
||||
# Queen side
|
||||
castlingAvailable.black.queen = false
|
||||
elif capture == piece.color.kingSideRook():
|
||||
# King side
|
||||
castlingAvailable.black.king = false
|
||||
else:
|
||||
# Unreachable
|
||||
discard
|
||||
# Has the king moved?
|
||||
if move.piece.kind == King:
|
||||
case move.piece.color:
|
||||
of White:
|
||||
castlingAvailable.white.king = false
|
||||
castlingAvailable.white.queen = false
|
||||
of Black:
|
||||
castlingAvailable.black.king = false
|
||||
castlingAvailable.black.queen = false
|
||||
else:
|
||||
discard
|
||||
|
||||
let previous = self.position
|
||||
if move.flag != Backwards:
|
||||
# Record final position for future reference
|
||||
self.positions.add(previous)
|
||||
# Create new position
|
||||
self.position = Position(plyFromRoot: self.position.plyFromRoot + 1,
|
||||
halfMoveClock: halfMoveClock,
|
||||
fullMoveCount: fullMoveCount,
|
||||
captured: emptyPiece(),
|
||||
turn: self.getActiveColor().opposite,
|
||||
castlingAvailable: castlingAvailable,
|
||||
# Updated at the next call to doMove()
|
||||
move: emptyMove(),
|
||||
pieces: previous.pieces,
|
||||
)
|
||||
|
||||
var location: Location
|
||||
if move.flag in [CastleShort, CastleLong]:
|
||||
# Move the rook onto the
|
||||
# correct file
|
||||
var
|
||||
location: Location
|
||||
target: Location
|
||||
if move.flag == CastleShort:
|
||||
location = move.piece.color.kingSideRook()
|
||||
target = shortCastleRook()
|
||||
else:
|
||||
location = move.piece.color.queenSideRook()
|
||||
target = longCastleRook()
|
||||
let rook = self.grid[location.row, location.col]
|
||||
let move = Move(startSquare: location, targetSquare: location + target, piece: rook, flag: move.flag)
|
||||
self.movePiece(move, attack=false)
|
||||
|
||||
# Update position and attack metadata
|
||||
if move.flag == Backwards:
|
||||
self.movePiece(move.targetSquare, move.startSquare)
|
||||
else:
|
||||
self.movePiece(move)
|
||||
|
||||
# Record final position for future reference
|
||||
self.positions.add(self.position)
|
||||
# Create new position with
|
||||
var newPos = Position(plyFromRoot: self.position.plyFromRoot + 1,
|
||||
halfMoveClock: halfMoveClock,
|
||||
fullMoveCount: fullMoveCount,
|
||||
captured: emptyPiece(),
|
||||
turn: self.getActiveColor().opposite,
|
||||
castlingAvailable: castlingAvailable,
|
||||
# Updated at the next call to doMove()
|
||||
move: emptyMove(),
|
||||
)
|
||||
# Check for double pawn push
|
||||
if move.piece.kind == Pawn and abs(move.startSquare.row - move.targetSquare.row) == 2:
|
||||
newPos.enPassantSquare = Move(piece: move.piece,
|
||||
if move.flag == DoublePush:
|
||||
self.position.enPassantSquare = Move(piece: move.piece,
|
||||
startSquare: (move.startSquare.row, move.startSquare.col),
|
||||
targetSquare: move.targetSquare + move.piece.color.bottomSide())
|
||||
else:
|
||||
newPos.enPassantSquare = emptyMove()
|
||||
|
||||
self.position = newPos
|
||||
self.position.enPassantSquare = emptyMove()
|
||||
|
||||
|
||||
proc spawnPiece(self: ChessBoard, location: Location, piece: Piece) =
|
||||
|
|
@ -1242,41 +1236,59 @@ proc spawnPiece(self: ChessBoard, location: Location, piece: Piece) =
|
|||
self.grid[location.row, location.col] = piece
|
||||
|
||||
|
||||
proc undoLastMove*(self: ChessBoard): Move {.discardable.} =
|
||||
## Undoes the last move, restoring the previous position.
|
||||
## If there are no positions to roll back to to, this is a
|
||||
## no-op. Returns the move that was performed (may be empty)
|
||||
proc undoMove*(self: ChessBoard, move: Move): Move {.discardable.} =
|
||||
## Undoes the given move if possible
|
||||
result = emptyMove()
|
||||
if self.positions.len() == 0:
|
||||
return
|
||||
var
|
||||
previous = self.positions[^1]
|
||||
oppositeMove = Move(piece: previous.move.piece, targetSquare: previous.move.startSquare, startSquare: previous.move.targetSquare)
|
||||
self.removePiece(previous.move.startSquare)
|
||||
var move: Move = move
|
||||
let previous = self.positions.pop()
|
||||
move.flag = Backwards
|
||||
self.doMove(move)
|
||||
self.position = previous
|
||||
if previous.move != emptyMove():
|
||||
self.spawnPiece(previous.move.startSquare, previous.move.piece)
|
||||
self.updateAttackedSquares()
|
||||
self.updatePositions(oppositeMove)
|
||||
if previous.captured != emptyPiece():
|
||||
self.spawnPiece(previous.move.targetSquare, previous.captured)
|
||||
discard self.positions.pop()
|
||||
return self.position.move
|
||||
self.position.move = move
|
||||
#self.updateLocations(move)
|
||||
return move
|
||||
|
||||
|
||||
proc isLegal(self: ChessBoard, move: Move): bool =
|
||||
proc isLegal(self: ChessBoard, move: Move, keep: bool = false): bool =
|
||||
## Returns whether the given move is legal
|
||||
var move = move
|
||||
if move.piece.kind == King and move.piece.color.longCastleKing() + move.startSquare == move.targetSquare:
|
||||
if move.piece.kind == King and longCastleKing() + move.startSquare == move.targetSquare:
|
||||
move.flag = CastleLong
|
||||
elif move.piece.kind == King and move.piece.color.shortCastleKing() + move.startSquare == move.targetSquare:
|
||||
elif move.piece.kind == King and shortCastleKing() + move.startSquare == move.targetSquare:
|
||||
move.flag = CastleShort
|
||||
if move.piece.kind == Pawn and move.piece.color.doublePush() + move.startSquare == move.targetSquare:
|
||||
move.flag = DoublePush
|
||||
if move notin self.generateMoves(move.startSquare):
|
||||
# Piece cannot arrive to destination (blocked
|
||||
# or otherwise invalid move)
|
||||
return false
|
||||
self.doMove(move)
|
||||
defer: self.undoLastMove()
|
||||
if not keep:
|
||||
defer: self.undoMove(move)
|
||||
# Move would reveal an attack
|
||||
# on our king: not allowed
|
||||
if self.inCheck(move.piece.color):
|
||||
return false
|
||||
# All checks have passed: move is legal
|
||||
result = true
|
||||
|
||||
|
||||
proc isLegalFast(self: ChessBoard, move: Move, keep: bool = false): bool =
|
||||
## Returns whether the given move is legal
|
||||
## assuming that the input move is pseudo legal
|
||||
var move = move
|
||||
if move.piece.kind == King and longCastleKing() + move.startSquare == move.targetSquare:
|
||||
move.flag = CastleLong
|
||||
elif move.piece.kind == King and shortCastleKing() + move.startSquare == move.targetSquare:
|
||||
move.flag = CastleShort
|
||||
if move.piece.kind == Pawn and move.piece.color.doublePush() + move.startSquare == move.targetSquare:
|
||||
move.flag = DoublePush
|
||||
self.position.move = move
|
||||
self.doMove(move)
|
||||
if not keep:
|
||||
defer: self.undoMove(move)
|
||||
# Move would reveal an attack
|
||||
# on our king: not allowed
|
||||
if self.inCheck(move.piece.color):
|
||||
|
|
@ -1287,11 +1299,26 @@ proc isLegal(self: ChessBoard, move: Move): bool =
|
|||
|
||||
proc makeMove*(self: ChessBoard, move: Move): Move {.discardable.} =
|
||||
## Like the other makeMove(), but with a Move object
|
||||
|
||||
result = move
|
||||
if not self.isLegal(move):
|
||||
self.position.move = move
|
||||
if move.flag == Backwards:
|
||||
self.doMove(result)
|
||||
let legal = self.isLegal(move, keep=true)
|
||||
if not legal:
|
||||
return emptyMove()
|
||||
self.doMove(result)
|
||||
result = self.position.move
|
||||
|
||||
|
||||
proc makeMoveFast*(self: ChessBoard, move: Move): Move {.discardable.} =
|
||||
## Like the other makeMove(), but uses isLegalFast
|
||||
result = move
|
||||
self.position.move = move
|
||||
if move.flag == Backwards:
|
||||
self.doMove(result)
|
||||
let legal = self.isLegalFast(move, keep=true)
|
||||
if not legal:
|
||||
return emptyMove()
|
||||
result = self.position.move
|
||||
|
||||
|
||||
proc makeMove*(self: ChessBoard, startSquare, targetSquare: string): Move {.discardable.} =
|
||||
|
|
@ -1360,6 +1387,63 @@ proc pretty*(self: ChessBoard): string =
|
|||
result &= "\x1b[0m"
|
||||
|
||||
|
||||
|
||||
|
||||
proc countLegalMoves*(self: ChessBoard, ply: int, verbose: bool = false, verboseIllegal: bool = false, current: int = 0): int =
|
||||
## Counts (and debugs) the number of legal positions reached after
|
||||
## the given number of half moves
|
||||
if ply == 0:
|
||||
result = 1
|
||||
else:
|
||||
var now: string
|
||||
for move in self.generateAllMoves():
|
||||
now = self.pretty()
|
||||
if self.isLegalFast(move, keep=true):
|
||||
if verbose:
|
||||
let canCastle = self.canCastle()
|
||||
echo "\x1Bc"
|
||||
echo &"Ply: {self.position.plyFromRoot} (move {current + result + 1})"
|
||||
echo &"Move: {move.startSquare.locationToAlgebraic()}{move.targetSquare.locationToAlgebraic()} (({move.startSquare.row}, {move.startSquare.col}) -> ({move.targetSquare.row}, {move.targetSquare.col}))"
|
||||
echo &"Turn: {move.piece.color}"
|
||||
echo &"Piece: {move.piece.kind}"
|
||||
echo &"In check: {(if self.inCheck(move.piece.color): \"yes\" else: \"no\")}"
|
||||
echo "Legal: yes"
|
||||
echo &"Flag: {move.flag}"
|
||||
echo &"Can castle:\n - King side: {(if canCastle.king: \"yes\" else: \"no\")}\n - Queen side: {(if canCastle.queen: \"yes\" else: \"no\")}"
|
||||
echo "\nBefore:"
|
||||
echo now
|
||||
echo "\nNow: "
|
||||
echo self.pretty()
|
||||
try:
|
||||
discard readLine(stdin)
|
||||
except IOError:
|
||||
discard
|
||||
except EOFError:
|
||||
discard
|
||||
result += self.countLegalMoves(ply - 1, verbose, verboseIllegal, result)
|
||||
elif verboseIllegal:
|
||||
let canCastle = self.canCastle()
|
||||
echo "\x1Bc"
|
||||
echo &"Ply: {self.position.plyFromRoot} (move {current + result + 1})"
|
||||
echo &"Move: {move.startSquare.locationToAlgebraic()}{move.targetSquare.locationToAlgebraic()} (({move.startSquare.row}, {move.startSquare.col}) -> ({move.targetSquare.row}, {move.targetSquare.col}))"
|
||||
echo &"Turn: {move.piece.color}"
|
||||
echo &"Piece: {move.piece.kind}"
|
||||
echo &"In check: {(if self.inCheck(move.piece.color): \"yes\" else: \"no\")}"
|
||||
echo "Legal: no"
|
||||
echo &"Flag: {move.flag}"
|
||||
echo &"Can castle:\n - King side: {(if canCastle.king: \"yes\" else: \"no\")}\n - Queen side: {(if canCastle.queen: \"yes\" else: \"no\")}"
|
||||
echo "\nBefore:"
|
||||
echo now
|
||||
echo "\nNow: "
|
||||
echo self.pretty()
|
||||
try:
|
||||
discard readLine(stdin)
|
||||
except IOError:
|
||||
discard
|
||||
except EOFError:
|
||||
discard
|
||||
self.undoMove(move)
|
||||
|
||||
when isMainModule:
|
||||
proc testPiece(piece: Piece, kind: PieceKind, color: PieceColor) =
|
||||
doAssert piece.kind == kind and piece.color == color, &"expected piece of kind {kind} and color {color}, got {piece.kind} / {piece.color} instead"
|
||||
|
|
@ -1417,6 +1501,6 @@ when isMainModule:
|
|||
when compileOption("profiler"):
|
||||
import nimprof
|
||||
|
||||
echo b.countLegalMoves(3)
|
||||
|
||||
b = newChessboardFromFEN("8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - -")
|
||||
echo b.countLegalMoves(2, verbose=true, verboseIllegal=true)
|
||||
echo "All tests were successful"
|
||||
Loading…
Reference in New Issue