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yeschess
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refactoring: renaming classes and functions

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Renamed the 'game' type to 'chess' to make more sense
of the existing filestructure.
Doubled functions where removed.
master
TiynGER 4 years ago
parent 3bc523c37a
commit 10098da82f
6 changed files with 937 additions and 962 deletions
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482
src/chess.nim
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@ -14,8 +14,8 @@ type
wq: bool # `wq` describes White queenside castle
bk: bool # `bk` describes Black kingside castle
bq: bool # `bq` describes Black queenside castle
Game* = object
## `Game` stores all important information of a chess game.
Chess* = object
## `Chess` stores all important information of a chess chess.
board*: Board
toMove*: Color
previousBoard: seq[Board]
@ -36,6 +36,7 @@ type
b: int # `b` describes the amount of bishops.
r: int # `r` describes the amount of rooks.
q: int # `q` describes the amount of queens.
Pieces = array[10,int]
const
Block* = 999 ## \
@ -103,8 +104,8 @@ const
## from whites perspective that are ttacks.
InsufficientMaterial: array[4, PieceAmount] = [
(0, 0, 0, 0, 0), # only kings
(0, 0, 1, 0, 0), # knight only
(0, 1, 0, 0, 0), # bishop only
(0, 0, 1, 0, 0), # bishop only
(0, 1, 0, 0, 0), # knight only
(0, 2, 0, 0, 0) # 2 knights
] ## `InsufficientMaterial` describes the pieces where no checkmate can be
## forced
@ -141,19 +142,13 @@ let
# `FileChar` maps the files of the chessboard to numbers for better
# conversion.
proc fieldToInd*(file: string, line: int): int =
## Calculate and return board index from `file` and `line` of a chess board.
## Returns -1 if the `field` was not input correct.
try:
return 1+(line+1)*10+(7-FileChar[file])
except IndexDefect, ValueError:
return -1
proc fieldToInd*(field: string): int =
## Calculate and return board index from `field` of a chess board.
## Returns -1 if the `field` was not input correct.
try:
return fieldToInd($field[0], parseInt($field[1]))
var file = $field[0]
var line = parseInt($field[1])
return 1+(line+1)*10+(7-FileChar[file])
except IndexDefect, ValueError:
return -1
@ -257,15 +252,15 @@ proc initBoard(board: array[0..63, int]): Board =
Block, Block, Block, Block, Block, Block, Block, Block, Block, Block]
return board
proc initGame*(): Game =
## Create and return a Game object.
let game = Game(board: initBoard(),
proc initChess*(): Chess =
## Create and return a Chess object.
let chess = Chess(board: initBoard(),
to_move: Color.White, previousBoard: @[], previousCastleRights: @[],
fiftyMoveCounter: 0, castleRights: (true, true, true, true))
return game
return chess
proc initGame*(board: array[0..63, int], color: Color): Game =
## Create and return a Game object based on a position of choice.
proc initChess*(board: array[0..63, int], color: Color): Chess =
## Create and return a Chess object based on a position of choice.
## `board` describes the pieces, `color` the color that is about to move.
let board = initBoard(board)
let compare = initBoard()
@ -286,69 +281,69 @@ proc initGame*(board: array[0..63, int], color: Color): Game =
bk = true
for ind in board.low..board.high:
same_piece = (board[ind] != compare[ind])
let game = Game(board: board,
let chess = Chess(board: board,
to_move: color, previousBoard: @[], previousCastleRights: @[],
fiftyMoveCounter: 0, castleRights: (wk, wq, bk, bq))
return game
return chess
proc echoBoard*(game: Game, color: Color) =
proc echoBoard*(chess: Chess, color: Color) =
## Prints out the given `board` with its pieces as characters and line
## indices from perspecive of `color`.
var line_str = ""
if (color == Color.Black):
for i in countup(0, len(game.board)-1):
if (game.board[i] == 999):
for i in countup(0, len(chess.board)-1):
if (chess.board[i] == 999):
continue
line_str &= PieceChar[game.board[i]] & " "
line_str &= PieceChar[chess.board[i]] & " "
if ((i+2) %% 10 == 0):
line_str &= $((int)((i)/10)-1) & "\n"
echo line_str
echo "h g f e d c b a"
else:
for i in countdown(len(game.board)-1, 0):
if (game.board[i] == 999):
for i in countdown(len(chess.board)-1, 0):
if (chess.board[i] == 999):
continue
line_str &= PieceChar[game.board[i]] & " "
line_str &= PieceChar[chess.board[i]] & " "
if ((i-1) %% 10 == 0):
line_str &= $((int)((i)/10)-1) & "\n"
echo line_str
echo "a b c d e f g h"
proc genPawnAttackDests(game: Game, field: int, color: Color): seq[int] =
proc genPawnAttackDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible attack destinations for a pawn with specific `color`
## located at index `field` of `game`.
## located at index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for attacks in Pawn_Moves_White_Attack:
dest = field + (attacks * ord(color))
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
if (target == 999 or ord(color) * target >= 0):
continue
res.add(dest)
return res
proc genPawnDoubleDests(game: Game, field: int, color: Color): seq[int] =
proc genPawnDoubleDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible double destinations for a pawn with specific `color`
## located at index `field` of `game`.
## located at index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for doubles in Pawn_Moves_White_Double:
dest = field + doubles * ord(color)
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
if ((target != 0) or (
game.board[dest+(S*ord(color))] != 0)):
chess.board[dest+(S*ord(color))] != 0)):
continue
if (color == Color.White and not (field in fieldToInd("h2")..fieldToInd("a2"))):
continue
@ -357,120 +352,120 @@ proc genPawnDoubleDests(game: Game, field: int, color: Color): seq[int] =
res.add(dest)
return res
proc genPawnDests(game: Game, field: int, color: Color): seq[int] =
proc genPawnDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible destinations for a pawn with specific `color` located at
## index `field` of `game`.
## index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for move in Pawn_Moves_White:
dest = field + move * ord(color)
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
if (target != 0 and target != ord(color) * WEnPassant):
continue
res.add(dest)
res.add(game.genPawnAttackDests(field, color))
res.add(game.genPawnDoubleDests(field, color))
res.add(chess.genPawnAttackDests(field, color))
res.add(chess.genPawnDoubleDests(field, color))
return res
proc genKnightDests(game: Game, field: int, color: Color): seq[int] =
proc genKnightDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible destinations for a knight with specific `color` located
## at index `field` of `game`.
## at index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for move in Knight_Moves:
dest = field + move
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
if (target == 999 or (ord(color) * target > 0 and ord(color) * target != WEnPassant)):
continue
res.add(dest)
return res
proc genBishopDests(game: Game, field: int, color: Color): seq[int] =
proc genBishopDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible destinations for a bishop with specific `color` located
## at index `field` of `game`.
## at index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for move in Bishop_Moves:
dest = field+move
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
while (target != 999 and (ord(color) * target <= 0) or target ==
WEnPassant or target == -WEnPassant):
res.add(dest)
if (ord(color) * target < 0 and ord(color) * target > -WEnPassant):
break
dest = dest+move
target = game.board[dest]
target = chess.board[dest]
return res
proc genRookDests(game: Game, field: int, color: Color): seq[int] =
proc genRookDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible destinations for a rook with specific `color` located at
## index `field` of `game`.
## index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for move in Rook_Moves:
dest = field+move
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
while (target != 999 and (ord(color) * target <= 0) or target ==
WEnPassant or target == -WEnPassant):
res.add(dest)
if (ord(color) * target < 0 and ord(color) * target > -WEnPassant):
break
dest = dest+move
target = game.board[dest]
target = chess.board[dest]
return res
proc genQueenDests(game: Game, field: int, color: Color): seq[int] =
proc genQueenDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible destinations for a queen with specific `color` located
## at index `field` of `game`.
## at index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for move in Queen_Moves:
dest = field+move
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
while (target != 999 and (ord(color) * target <= 0) or target ==
WEnPassant or target == -WEnPassant):
res.add(dest)
if (ord(color) * target < 0 and ord(color) * target > -WEnPassant):
break
dest = dest+move
target = game.board[dest]
target = chess.board[dest]
return res
proc genKingCastleDest(game: Game, field: int, color: Color): seq[int] =
proc genKingCastleDest(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible castle destinations for a king with specific `color`
## located at index `field` of `game`
## located at index `field` of `chess`
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
@ -479,11 +474,11 @@ proc genKingCastleDest(game: Game, field: int, color: Color): seq[int] =
var half_target: int
for castle in King_Moves_White_Castle:
dest = field + castle
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
half_dest = field + (int)castle/2
half_target = game.board[half_dest]
half_target = chess.board[half_dest]
if (target == 999 or (target != 0)):
continue
if (half_target == 999 or (half_target != 0)):
@ -491,90 +486,90 @@ proc genKingCastleDest(game: Game, field: int, color: Color): seq[int] =
res.add(dest)
return res
proc genKingDests(game: Game, field: int, color: Color): seq[int] =
proc genKingDests(chess: Chess, field: int, color: Color): seq[int] =
## Generate possible destinations for a king with specific `color`
## located at index `field` of `game`.
## located at index `field` of `chess`.
## Returns a sequence of possible indices to move to.
if (not field in game.board.low..game.board.high):
if (not field in chess.board.low..chess.board.high):
return @[]
var res = newSeq[int]()
var dest: int
var target: int
for move in King_Moves:
dest = field + move
if (not dest in game.board.low..game.board.high):
if (not dest in chess.board.low..chess.board.high):
continue
target = game.board[dest]
target = chess.board[dest]
if (target == 999 or (ord(color) * target > 0 and ord(color) * target != WEnPassant)):
continue
res.add(dest)
res.add(game.genKingCastleDest(field, color))
res.add(chess.genKingCastleDest(field, color))
return res
proc pieceOn(game: Game, color: Color, sequence: seq[int],
proc pieceOn(chess: Chess, color: Color, sequence: seq[int],
pieceID: int): bool =
## Returns true if the `PieceID` of a given `color` is in `sequence` else
## wrong.
for check in sequence:
if game.board[check] == ord(color) * -1 * pieceID:
if chess.board[check] == ord(color) * -1 * pieceID:
return true
return false
proc isAttacked(game: Game, position: int, color: Color): bool =
## Returns true if a `position` in a `game` is attacked by the opposite
proc isAttacked(chess: Chess, position: int, color: Color): bool =
## Returns true if a `position` in a `chess` is attacked by the opposite
## color of `color`.
var attacked = false
attacked = attacked or game.pieceOn(color, game.genPawnAttackDests(
attacked = attacked or chess.pieceOn(color, chess.genPawnAttackDests(
position, color), WPawn)
attacked = attacked or game.pieceOn(color, game.genQueenDests(position,
attacked = attacked or chess.pieceOn(color, chess.genQueenDests(position,
color), WQueen)
attacked = attacked or game.pieceOn(color, game.genKingDests(position,
attacked = attacked or chess.pieceOn(color, chess.genKingDests(position,
color), WKing)
attacked = attacked or game.pieceOn(color, game.genRookDests(position,
attacked = attacked or chess.pieceOn(color, chess.genRookDests(position,
color), WRook)
attacked = attacked or game.pieceOn(color, game.genBishopDests(position,
attacked = attacked or chess.pieceOn(color, chess.genBishopDests(position,
color), WBishop)
attacked = attacked or game.pieceOn(color, game.genKnightDests(position,
attacked = attacked or chess.pieceOn(color, chess.genKnightDests(position,
color), WKnight)
return attacked
proc isInCheck*(game: Game, color: Color): bool =
## Returns true if the king of a given `color` is in check in a `game`.
proc isInCheck*(chess: Chess, color: Color): bool =
## Returns true if the king of a given `color` is in check in a `chess`.
var king_pos: int
for i in countup(0, game.board.high):
if game.board[i] == ord(color) * WKing:
for i in countup(0, chess.board.high):
if chess.board[i] == ord(color) * WKing:
king_pos = i
return game.isAttacked(king_pos, color)
return chess.isAttacked(king_pos, color)
proc uncheckedMove(game: var Game, start: int, dest: int): bool {.discardable.} =
proc uncheckedMove(chess: var Chess, start: int, dest: int): bool {.discardable.} =
## Moves a piece if possible from `start` position to `dest` position in a
## `game`.
let piece = game.board[start]
game.board[start] = 0
game.board[dest] = piece
## `chess`.
let piece = chess.board[start]
chess.board[start] = 0
chess.board[dest] = piece
if (start == fieldToInd("e1") or start == fieldToInd("a1")):
game.castleRights.wq = false
chess.castleRights.wq = false
if (start == fieldToInd("e1") or start == fieldToInd("h1")):
game.castleRights.wk = false
chess.castleRights.wk = false
if (start == fieldToInd("e8") or start == fieldToInd("a8")):
game.castleRights.bq = false
chess.castleRights.bq = false
if (start == fieldToInd("e8") or start == fieldToInd("h8")):
game.castleRights.bk = false
chess.castleRights.bk = false
if (dest == fieldToInd("e1") or dest == fieldToInd("a1")):
game.castleRights.wq = false
chess.castleRights.wq = false
if (dest == fieldToInd("e1") or dest == fieldToInd("h1")):
game.castleRights.wk = false
chess.castleRights.wk = false
if (dest == fieldToInd("e8") or dest == fieldToInd("a8")):
game.castleRights.bq = false
chess.castleRights.bq = false
if (dest == fieldToInd("e8") or dest == fieldToInd("h8")):
game.castleRights.bk = false
chess.castleRights.bk = false
return true
proc moveLeadsToCheck(game: Game, start: int, dest: int,
proc moveLeadsToCheck(chess: Chess, start: int, dest: int,
color: Color): bool =
## Returns true if a move from `start` to `dest` in a `game` puts the `color`
## Returns true if a move from `start` to `dest` in a `chess` puts the `color`
## king in check.
var check = game
var check = chess
check.uncheckedMove(start, dest)
return check.isInCheck(color)
@ -588,15 +583,15 @@ proc genPawnPromotion(move: Move, color: Color): seq[Move] =
promotions.add(getMove(start, dest, piece, color))
return promotions
proc genLegalPawnMoves(game: Game, field: int, color: Color): seq[Move] =
## Generates all legal pawn moves in a `game` starting from `field` for a
proc genLegalPawnMoves(chess: Chess, field: int, color: Color): seq[Move] =
## Generates all legal pawn moves in a `chess` starting from `field` for a
## `color`.
if game.board[field] != WPawn * ord(color):
if chess.board[field] != WPawn * ord(color):
return @[]
var res = newSeq[Move]()
var moves = game.genPawnDests(field, color)
var moves = chess.genPawnDests(field, color)
for dest in moves:
if not game.moveLeadsToCheck(field, dest, color):
if not chess.moveLeadsToCheck(field, dest, color):
var promotions = genPawnPromotion(getMove(field, dest, color), color)
if promotions != @[]:
res.add(promotions)
@ -604,107 +599,107 @@ proc genLegalPawnMoves(game: Game, field: int, color: Color): seq[Move] =
res.add(getMove(field, dest, color))
return res
proc genLegalKnightMoves(game: Game, field: int, color: Color): seq[Move] =
## Generates all legal knight moves in a `game` starting from `field` for a
proc genLegalKnightMoves(chess: Chess, field: int, color: Color): seq[Move] =
## Generates all legal knight moves in a `chess` starting from `field` for a
## `color`.
if game.board[field] != WKnight * ord(color):
if chess.board[field] != WKnight * ord(color):
return @[]
var res = newSeq[Move]()
var moves = game.genKnightDests(field, color)
var moves = chess.genKnightDests(field, color)
for dest in moves:
if not game.moveLeadsToCheck(field, dest, color):
if not chess.moveLeadsToCheck(field, dest, color):
res.add(getMove(field, dest, color))
return res
proc genLegalBishopMoves(game: Game, field: int, color: Color): seq[Move] =
## Generates all legal bishop moves in a `game` starting from `field` for a
proc genLegalBishopMoves(chess: Chess, field: int, color: Color): seq[Move] =
## Generates all legal bishop moves in a `chess` starting from `field` for a
## `color`.
if game.board[field] != WBishop * ord(color):
if chess.board[field] != WBishop * ord(color):
return @[]
var res = newSeq[Move]()
var moves = game.genBishopDests(field, color)
var moves = chess.genBishopDests(field, color)
for dest in moves:
if not game.moveLeadsToCheck(field, dest, color):
if not chess.moveLeadsToCheck(field, dest, color):
res.add(getMove(field, dest, color))
return res
proc genLegalRookMoves(game: Game, field: int, color: Color): seq[Move] =
## Generates all legal rook moves in a `game` starting from `field` for a
proc genLegalRookMoves(chess: Chess, field: int, color: Color): seq[Move] =
## Generates all legal rook moves in a `chess` starting from `field` for a
## `color`.
if game.board[field] != WRook * ord(color):
if chess.board[field] != WRook * ord(color):
return @[]
var res = newSeq[Move]()
var moves = game.genRookDests(field, color)
var moves = chess.genRookDests(field, color)
for dest in moves:
if not game.moveLeadsToCheck(field, dest, color):
if not chess.moveLeadsToCheck(field, dest, color):
res.add(getMove(field, dest, color))
return res
proc genLegalQueenMoves(game: Game, field: int, color: Color): seq[Move] =
## Generates all legal queen moves in a `game` starting from `field` for a
proc genLegalQueenMoves(chess: Chess, field: int, color: Color): seq[Move] =
## Generates all legal queen moves in a `chess` starting from `field` for a
## `color`.
if game.board[field] != WQueen * ord(color):
if chess.board[field] != WQueen * ord(color):
return @[]
var res = newSeq[Move]()
var moves = game.genQueenDests(field, color)
var moves = chess.genQueenDests(field, color)
for dest in moves:
if not game.moveLeadsToCheck(field, dest, color):
if not chess.moveLeadsToCheck(field, dest, color):
res.add(getMove(field, dest, color))
return res
proc genLegalKingMoves(game: Game, field: int, color: Color): seq[Move] =
## Generates all legal king moves in a `game` starting from `field` for a
proc genLegalKingMoves(chess: Chess, field: int, color: Color): seq[Move] =
## Generates all legal king moves in a `chess` starting from `field` for a
## `color`.
if game.board[field] != WKing * ord(color):
if chess.board[field] != WKing * ord(color):
return @[]
var res = newSeq[Move]()
var moves = game.genKingDests(field, color)
var moves = chess.genKingDests(field, color)
for dest in moves:
if field - dest == W+W and game.isAttacked(dest+W, color):
if field - dest == W+W and chess.isAttacked(dest+W, color):
continue
if field - dest == E+E and game.isAttacked(dest+E, color):
if field - dest == E+E and chess.isAttacked(dest+E, color):
continue
if not game.moveLeadsToCheck(field, dest, color):
if not chess.moveLeadsToCheck(field, dest, color):
res.add(getMove(field, dest, color))
return res
proc genLegalMoves*(game: Game, field: int, color: Color): seq[Move] =
## Generates all legal moves in a `game` starting from `field` for a `color`.
proc genLegalMoves*(chess: Chess, field: int, color: Color): seq[Move] =
## Generates all legal moves in a `chess` starting from `field` for a `color`.
var legal_moves = newSeq[Move]()
var target = ord(color) * game.board[field]
var target = ord(color) * chess.board[field]
if 0 < target and target < WEnPassant:
legal_moves = case target:
of WPawn:
game.genLegalPawnMoves(field, color)
chess.genLegalPawnMoves(field, color)
of WKnight:
game.genLegalKnightMoves(field, color)
chess.genLegalKnightMoves(field, color)
of WBishop:
game.genLegalBishopMoves(field, color)
chess.genLegalBishopMoves(field, color)
of WRook:
game.genLegalRookMoves(field, color)
chess.genLegalRookMoves(field, color)
of WQueen:
game.genLegalQueenMoves(field, color)
chess.genLegalQueenMoves(field, color)
of WKing:
game.genLegalKingMoves(field, color)
chess.genLegalKingMoves(field, color)
else:
@[]
return legal_moves
proc genLegalMoves*(game: Game, color: Color): seq[Move] =
## Generates all legal moves in a `game` for a `color`.
proc genLegalMoves*(chess: Chess, color: Color): seq[Move] =
## Generates all legal moves in a `chess` for a `color`.
var legal_moves = newSeq[Move]()
for field in game.board.low..game.board.high:
legal_moves.add(game.genLegalMoves(field, color))
for field in chess.board.low..chess.board.high:
legal_moves.add(chess.genLegalMoves(field, color))
return legal_moves
proc castling(game: var Game, kstart: int, dest_kingside: bool,
proc castling(chess: var Chess, kstart: int, dest_kingside: bool,
color: Color): bool {.discardable.} =
## Tries to castle in a given `game` with the king of a given `color` from
## Tries to castle in a given `chess` with the king of a given `color` from
## `kstart`.
## `dest_kingside` for kingside castling, else castling is queenside.
## This process checks for the legality of the move and performs the switch
## of `game.to_move`
if game.toMove != color:
## of `chess.to_move`
if chess.toMove != color:
return false
var kdest = kstart
var rstart: int
@ -715,32 +710,32 @@ proc castling(game: var Game, kstart: int, dest_kingside: bool,
rstart = kstart + (E+E+E)
rdest = rstart + (W+W)
if (color == Color.White):
rights = game.castleRights.wk
rights = chess.castleRights.wk
else:
rights = game.castleRights.bk
rights = chess.castleRights.bk
else:
rstart = kstart + (W+W+W+W)
rdest = rstart + (E+E+E)
kdest = kstart + (W+W)
if (color == Color.White):
rights = game.castleRights.bq
rights = chess.castleRights.bq
else:
rights = game.castleRights.bq
rights = chess.castleRights.bq
if (rights):
var check = false
if (dest_kingside):
check = check or game.isAttacked(kstart, color)
check = check or game.isAttacked(kstart+(E), color)
check = check or game.isAttacked(kstart+(E+E), color)
check = check or chess.isAttacked(kstart, color)
check = check or chess.isAttacked(kstart+(E), color)
check = check or chess.isAttacked(kstart+(E+E), color)
else:
check = check or game.isAttacked(kstart, color)
check = check or game.isAttacked(kstart+(W), color)
check = check or game.isAttacked(kstart+(W+W), color)
check = check or chess.isAttacked(kstart, color)
check = check or chess.isAttacked(kstart+(W), color)
check = check or chess.isAttacked(kstart+(W+W), color)
if check:
return false
game.uncheckedMove(kstart, kdest)
game.uncheckedMove(rstart, rdest)
game.toMove = Color(ord(game.toMove)*(-1))
chess.uncheckedMove(kstart, kdest)
chess.uncheckedMove(rstart, rdest)
chess.toMove = Color(ord(chess.toMove)*(-1))
return true
return false
@ -750,128 +745,105 @@ proc removeEnPassant(board: var Board, color: Color): void =
if board[field] == ord(color) * WEnPassant:
board[field] = 0
proc checkedMove*(game: var Game, move: Move): bool {.discardable.} =
## Tries to make a `move` in a given `game``.
proc checkedMove*(chess: var Chess, move: Move): bool {.discardable.} =
## Tries to make a `move` in a given `chess``.
## This process checks for the legality of the move and performs the switch
## of `game.to_move` with exception of castling (castling() switches).
## of `chess.to_move` with exception of castling (castling() switches).
let start = move.start
let dest = move.dest
let color = move.color
let prom = move.prom
if (game.toMove != color or start == -1 or dest == -1):
if (chess.toMove != color or start == -1 or dest == -1):
return false
var sequence = newSeq[Move]()
let piece = game.board[start]
let piece = chess.board[start]
var createEnPassant = false
var capturedEnPassant = false
var fiftyMoveRuleReset = false
var move: Move
move = getMove(start, dest, color)
if (piece == WPawn * ord(color)):
createEnPassant = dest in game.genPawnDoubleDests(start, color)
capturedEnPassant = (game.board[dest] == -1 * ord(color) * WEnPassant)
createEnPassant = dest in chess.genPawnDoubleDests(start, color)
capturedEnPassant = (chess.board[dest] == -1 * ord(color) * WEnPassant)
fiftyMoveRuleReset = true
if (game.board[move.dest] != 0):
if (chess.board[move.dest] != 0):
fiftyMoveRuleReset = true
sequence.add(game.genLegalMoves(start, color))
sequence.add(chess.genLegalMoves(start, color))
# TODO: don't generate all legal moves, just check if result is legal and reachable
if (move in sequence):
game.board.removeEnPassant(color)
chess.board.removeEnPassant(color)
if (piece == WKing * ord(color) and (start - dest == (W+W))):
return game.castling(start, true, color)
return chess.castling(start, true, color)
elif (piece == WKing * ord(color) and (start - dest == (E+E))):
return game.castling(start, false, color)
return chess.castling(start, false, color)
else:
game.uncheckedMove(start, dest)
game.toMove = Color(ord(game.toMove)*(-1))
chess.uncheckedMove(start, dest)
chess.toMove = Color(ord(chess.toMove)*(-1))
if createEnPassant:
game.board[dest-(N*ord(color))] = WEnPassant * ord(color)
chess.board[dest-(N*ord(color))] = WEnPassant * ord(color)
if capturedEnPassant:
game.board[dest-(N*ord(color))] = 0
chess.board[dest-(N*ord(color))] = 0
if ((90 < dest and dest < 99) or (20 < dest and dest < 29)) and
game.board[dest] == WPawn * ord(color):
game.board[dest] = prom
var prevBoard = game.previousBoard
var prevCastle = game.previousCastleRights
game.previousBoard.add(game.board)
game.previousCastleRights.add(game.castleRights)
game.fiftyMoveCounter = game.fiftyMoveCounter + 1
chess.board[dest] == WPawn * ord(color):
chess.board[dest] = prom
var prevBoard = chess.previousBoard
var prevCastle = chess.previousCastleRights
chess.previousBoard.add(chess.board)
chess.previousCastleRights.add(chess.castleRights)
chess.fiftyMoveCounter = chess.fiftyMoveCounter + 1
if fiftyMoveRuleReset:
game.fiftyMoveCounter = 0
chess.fiftyMoveCounter = 0
return true
proc hasNoMoves(game: Game, color: Color): bool =
## Returns true if the `color` player has no legal moves in a `game`.
return (game.genLegalMoves(color) == @[])
proc hasNoMoves(chess: Chess, color: Color): bool =
## Returns true if the `color` player has no legal moves in a `chess`.
return (chess.genLegalMoves(color) == @[])
proc isCheckmate*(game: Game, color: Color): bool =
## Returns true if the `color` player is checkmate in a `game`.
return game.hasNoMoves(color) and game.isInCheck(color)
proc isCheckmate*(chess: Chess, color: Color): bool =
## Returns true if the `color` player is checkmate in a `chess`.
return chess.hasNoMoves(color) and chess.isInCheck(color)
proc threeMoveRep(game: Game): bool =
proc threeMoveRep(chess: Chess): bool =
## Returns true if a 3-fold repitition happened on the last move of the
## `game`.
if game.previousBoard == []:
## `chess`.
if chess.previousBoard == []:
return false
var lastState = game.previousBoard[game.previousBoard.high]
var lastCastleRights = game.previousCastleRights[game.previousBoard.high]
var lastState = chess.previousBoard[chess.previousBoard.high]
var lastCastleRights = chess.previousCastleRights[chess.previousBoard.high]
var reps = 0
for stateInd in (game.previousBoard.low)..(game.previousBoard.high):
if (game.previousBoard[stateInd] == lastState and game.previousCastleRights[
for stateInd in (chess.previousBoard.low)..(chess.previousBoard.high):
if (chess.previousBoard[stateInd] == lastState and chess.previousCastleRights[
stateInd] == lastCastleRights):
reps = reps + 1
return reps >= 3
proc fiftyMoveRule(game: Game): bool =
## Returns true if a draw can be claimed by the 50 move rule in a `game`.
return game.fiftyMoveCounter >= 100
proc fiftyMoveRule(chess: Chess): bool =
## Returns true if a draw can be claimed by the 50 move rule in a `chess`.
return chess.fiftyMoveCounter >= 100
proc isDrawClaimable*(game: Game): bool =
proc isDrawClaimable*(chess: Chess): bool =
## Returns true if a draw is claimable by either player.
return game.threeMoveRep() or game.fiftyMoveRule()
return chess.threeMoveRep() or chess.fiftyMoveRule()
proc checkInsufficientMaterial(board: Board): bool =
## Checks for combinations of pieces on a `board`, where no checkmate can be
## forced.
## Returns true if no player can force a checkmate to the other.
var wp = 0
var wn = 0
var wb = 0
var wr = 0
var wq = 0
var bp = 0
var bn = 0
var bb = 0
var br = 0
var bq = 0
var pieces: Pieces
for field in board.low..board.high:
case board[field]:
of WPawn:
wp += 1
of BPawn:
bp += 1
of WKnight:
wn += 1
of BKnight:
bn += 1
of WBishop:
wb += 1
of BBishop:
bb += 1
of WRook:
wr += 1
of BRook:
br += 1
of WQueen:
wq += 1
of BQueen:
bq += 1
else:
continue
let wpieces: PieceAmount = (wp, wn, wb, wr, wq)
let bpieces: PieceAmount = (bp, bn, bb, br, bq)
var piece = board[field]
var index: int
if piece >= WPawn and piece <= WRook:
index = piece - WPawn # map lowest value to 0
pieces[index] += 1
elif piece <= BPawn and piece >= BRook:
index = WRook - piece # map black pieces after whites
pieces[index] += 1
let wpieces: PieceAmount = (pieces[0], pieces[1], pieces[2], pieces[3], pieces[4])
let bpieces: PieceAmount = (pieces[5], pieces[6], pieces[7], pieces[8], pieces[9])
return (wpieces in InsufficientMaterial) and (bpieces in InsufficientMaterial)
proc isStalemate*(game: Game, color: Color): bool =
## Returns true if the `color` player is stalemate in a `game`.
return (game.hasNoMoves(color) and not game.isInCheck(color)) or
game.board.checkInsufficientMaterial()
proc isStalemate*(chess: Chess, color: Color): bool =
## Returns true if the `color` player is stalemate in a `chess`.
return (chess.hasNoMoves(color) and not chess.isInCheck(color)) or
chess.board.checkInsufficientMaterial()

1262
src/chessTest.nim
View File

File diff suppressed because it is too large Load Diff

54
src/engine.nim
Unescape View File

@ -1,9 +1,9 @@
import ./chess
import ./chess.nim
type
MoveTree* = object
## `Movetree` is a visualization for possible moves.
game*: Game
chess*: Chess
evaluation: float
children*: seq[Movetree]
@ -17,10 +17,10 @@ const
DrawVal = 0 ## `DrawVal` is the engines value for a draw.
LoVal = -1000000 ## `LoVal` is a value always lower than any evaluation.
proc pieceEval*(game: Game): int =
proc pieceEval*(chess: Chess): int =
## Returns the evaluation of existing pieces on the `board`
var evaluation = DrawVal
for square in game.board:
for square in chess.board:
case square:
of WPawn:
evaluation += ord(Color.White) * PawnVal
@ -46,56 +46,56 @@ proc pieceEval*(game: Game): int =
continue
return evaluation
proc evaluate(game: Game): int =
## Returns a complete evaluation of a `game` with player `toMove` about to make
proc evaluate(chess: Chess): int =
## Returns a complete evaluation of a `chess` with player `toMove` about to make
## a move.
var evaluation: int
if game.isCheckmate(game.toMove):
evaluation = ord(game.toMove) * CheckmateVal
if game.isStalemate(game.toMove):
if chess.isCheckmate(chess.toMove):
evaluation = ord(chess.toMove) * CheckmateVal
if chess.isStalemate(chess.toMove):
evaluation = DrawVal
else:
evaluation = game.pieceEval()
if game.isDrawClaimable():
if game.toMove == Color.White:
evaluation = chess.pieceEval()
if chess.isDrawClaimable():
if chess.toMove == Color.White:
evaluation = max(DrawVal, evaluation)
else:
evaluation = min(DrawVal, evaluation)
return evaluation
proc spanMoveTree*(game: Game, depth: int): MoveTree =
## Create and return a Movetree of a given `game` with a given maximum `depth`.
proc spanMoveTree*(chess: Chess, depth: int): MoveTree =
## Create and return a Movetree of a given `chess` with a given maximum `depth`.
var mTree: MoveTree
mTree.game = game
if depth != 0 and not game.isCheckmate(game.toMove) and not game.isStalemate(game.toMove):
let possibleMoves = game.genLegalMoves(game.toMove)
mTree.chess = chess
if depth != 0 and not chess.isCheckmate(chess.toMove) and not chess.isStalemate(chess.toMove):
let possibleMoves = chess.genLegalMoves(chess.toMove)
for move in possibleMoves:
var tmpGame = game
tmpGame.checkedMove(move)
mTree.children.add(spanMoveTree(tmpGame, depth-1))
var tmpChess = chess
tmpChess.checkedMove(move)
mTree.children.add(spanMoveTree(tmpChess, depth-1))
return mTree
proc negaMax*(mTree: MoveTree): int =
## Return the value of the root node of a given `MoveTree`
if mTree.children == []:
return mTree.game.evaluate()
return mTree.chess.evaluate()
var bestVal = LoVal
for child in mTree.children:
var tmpVal = -negaMax(child)
bestVal = max(bestVal, tmpVal)
return bestVal
proc bestMove*(game: Game, depth: int): Move =
## Generate a MoveTree of a `game` with a given `depth`, run negaMax and return
proc bestMove*(chess: Chess, depth: int): Move =
## Generate a MoveTree of a `chess` with a given `depth`, run negaMax and return
## the best evaluated move.
var moves = game.genLegalMoves(game.toMove)
var moves = chess.genLegalMoves(chess.toMove)
var bestMove: Move
var bestEval: int
bestEval = LoVal
for move in moves:
var tmpGame = game
tmpGame.checkedMove(move)
var tmpMTree = tmpGame.spanMoveTree(depth)
var tmpChess = chess
tmpChess.checkedMove(move)
var tmpMTree = tmpChess.spanMoveTree(depth)
var tmpEval = -tmpMTree.negaMax()
echo("move:", moveToNotation(move),"; eval:", tmpEval)
if tmpEval > bestEval:

34
src/engineTest.nim
Unescape View File

@ -1,18 +1,18 @@
import einheit
import ./chess
import ./engine
import ./chess.nim
import ./engine.nim
testSuite GameTest of TestSuite:
testSuite ChessTest of TestSuite:
var
game: Game
chess: Chess
method setup() =
self.game = initGame()
self.chess = initChess()
method testPieceEvalStalemate() =
self.game = initGame([
self.chess = initChess([
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, WKing, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
@ -22,11 +22,11 @@ testSuite GameTest of TestSuite:
0, 0, 0, 0, 0, BKing, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
], Color.Black)
var pieceEvaluation = self.game.pieceEval()
var pieceEvaluation = self.chess.pieceEval()
self.check(pieceEvaluation == 0)
method testSpanMoveTree() =
self.game = initGame([
self.chess = initChess([
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, WKing, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
@ -36,11 +36,11 @@ testSuite GameTest of TestSuite:
0, 0, 0, 0, 0, BKing, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
], Color.Black)
var mTree = self.game.spanMoveTree(1)
var mTree = self.chess.spanMoveTree(1)
self.check(mTree.children == [])
method testBestMoveProm() =
self.game = initGame([
self.chess = initChess([
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, WKing, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
@ -50,7 +50,7 @@ testSuite GameTest of TestSuite:
0, 0, 0, WPawn, 0, BKing, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
], Color.White)
var testBestMove = self.game.bestMove(2)
var testBestMove = self.chess.bestMove(2)
self.check(testBestMove.start != 0)
self.check(indToField(testBestMove.start) == "e7")
self.check(indToField(testBestMove.dest) == "e8")
@ -58,7 +58,7 @@ testSuite GameTest of TestSuite:
method testBestMoveStopProm() =
self.game = initGame([
self.chess = initChess([
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, WKing, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
@ -68,13 +68,13 @@ testSuite GameTest of TestSuite:
0, 0, 0, 0, WPawn, BKing, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
], Color.Black)
var testBestMove = self.game.bestMove(2)
var testBestMove = self.chess.bestMove(2)
self.check(testBestMove.start != 0)
self.check(indToField(testBestMove.start) == "c7")
self.check(indToField(testBestMove.dest) == "d7")
method testBestMoveTacticBlack() =
self.game = initGame([
self.chess = initChess([
0, 0, 0, 0, 0, 0, 0, 0,
0, WRook, 0, WKing, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
@ -84,12 +84,12 @@ testSuite GameTest of TestSuite:
0, BRook, 0, 0, 0, BKing, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
], Color.Black)
var testBestMove = self.game.bestMove(2)
var testBestMove = self.chess.bestMove(2)
self.check(testBestMove.start != 0)
self.check(indToField(testBestMove.start) != "g5" or indToField(testBestMove.dest) != "f4")
method testBestMoveTacticWhite() =
self.game = initGame([
self.chess = initChess([
0, 0, 0, 0, 0, 0, 0, 0,
0, WRook, 0, WKing, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
@ -99,7 +99,7 @@ testSuite GameTest of TestSuite:
0, BRook, 0, 0, 0, BKing, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
], Color.White)
var testBestMove = self.game.bestMove(2)
var testBestMove = self.chess.bestMove(2)
self.check(testBestMove.start != 0)
self.check(indToField(testBestMove.start) != "g4" or indToField(testBestMove.dest) != "f5")

46
src/game.nim
Unescape View File

@ -5,52 +5,53 @@ import ./engine.nim
proc runGameHotseat*(): void =
## Initializes and runs a game of chess as hotseat.
var game = initGame()
var chess = initChess()
var draw: string
game.echoBoard(game.toMove)
while not game.isCheckmate(game.toMove) and not game.isStalemate(game.toMove):
chess.echoBoard(chess.toMove)
while not chess.isCheckmate(chess.toMove) and not chess.isStalemate(chess.toMove):
echo "Make a move"
echo game.toMove
echo chess.toMove
var move = readLine(stdin)
while not game.checkedMove(notationToMove(move, game.toMove)):
while not chess.checkedMove(notationToMove(move, chess.toMove)):
move = readLine(stdin)
game.echoBoard(game.toMove)
if (game.isDrawClaimable):
chess.echoBoard(chess.toMove)
if (chess.isDrawClaimable):
echo "Do you want to claim a draw? (y/N)"
draw = readLine(stdin)
if (draw == "y"):
echo "Draw claimed"
break
if game.isCheckmate(game.toMove):
echo $game.toMove & " was checkmated"
if game.isStalemate(game.toMove):
if chess.isCheckmate(chess.toMove):
echo $chess.toMove & " was checkmated"
if chess.isStalemate(chess.toMove):
echo "Stalemate"
proc runGameSolo*(color: Color, difficulty: int): void =
## Initializes and runs a solo game of chess.
## The player plays as `color`.
var game = initGame()
echo("run game")
var chess = initChess()
var draw: string
while not game.isCheckmate(game.toMove) and not game.isStalemate(game.toMove):
if (game.toMove == color):
game.echoBoard(color)
while not chess.isCheckmate(chess.toMove) and not chess.isStalemate(chess.toMove):
if (chess.toMove == color):
chess.echoBoard(color)
echo "Make a move"
var hMove = readLine(stdin)
while not game.checkedMove(notationToMove(hMove, game.toMove)):
while not chess.checkedMove(notationToMove(hMove, chess.toMove)):
hMove = readLine(stdin)
game.echoBoard(color)
if (game.isDrawClaimable):
chess.echoBoard(color)
if (chess.isDrawClaimable):
echo "Do you want to claim a draw? (y/N)"
draw = readLine(stdin)
if (draw == "y"):
echo "Draw claimed"
break
else:
var cMove = bestMove(game, 3)
game.checkedMove(cMove)
if game.isCheckmate(game.toMove):
echo $game.toMove & " was checkmated"
if game.isStalemate(game.toMove):
var cMove = bestMove(chess, difficulty)
chess.checkedMove(cMove)
if chess.isCheckmate(chess.toMove):
echo $chess.toMove & " was checkmated"
if chess.isStalemate(chess.toMove):
echo "Stalemate"
proc menu(): void =
@ -88,4 +89,5 @@ proc menu(): void =
echo("\n\n\n")
runGameHotseat()
when isMainModule:
menu()

17
src/lichess.nim → src/lichessBridge.nim
Unescape View File

@ -11,14 +11,14 @@ var session = berserk.TokenSession(secret.api_token)
var client = berserk.Client(session=session)
let engineID = "tiyn-ychess"
let engineDifficulty = 3
let engineDifficulty = 2
let toAccept = ["tiynger"]
proc playGame(id: string) {.async.} =
proc playLichessGame(id: string) {.async.} =
## Plays a lichess game with `id` asynchronously.
var color: Color
var game = initGame()
var chess = initChess()
for event in client.bots.stream_game_state(id):
echo(event)
if $event["type"] in ["gameState", "gameFull"]:
@ -35,11 +35,11 @@ proc playGame(id: string) {.async.} =
movesString = event["moves"]
if $movesString != "":
var moves = movesString.split(" ")
game.checkedMove(notationToMove($moves[-1], game.toMove))
game.echoBoard(game.toMove)
if game.toMove == color:
chess.checkedMove(notationToMove($moves[-1], chess.toMove))
chess.echoBoard(chess.toMove)
if chess.toMove == color:
echo("engine has to make a move")
var bestMove = moveToNotation(game.bestMove(engineDifficulty))
var bestMove = moveToNotation(chess.bestMove(engineDifficulty))
echo(bestMove)
discard client.bots.make_move(id, bestMove)
@ -56,10 +56,11 @@ proc acceptChallenge(whiteList: openArray[string]): void =
if challenger in whiteList and speed == "correspondence":
echo("challenge of ", challenger, " whiteList: ", id)
discard client.bots.accept_challenge(id)
discard playGame($event["challenge"]["id"])
discard playLichessGame($event["challenge"]["id"])
else:
discard client.bots.decline_challenge(id)
echo("challenge of ", challenger, " whiteList: ", id)
when isMainModule:
acceptChallenge(toAccept)
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