2012-08-08 38 views
1

嗨!我正在制作一个象棋引擎,并且在make/unmake方法中遇到了一些问题。国际象棋编程make and unmake move

我有一个Piece类,它包含了棋子类型(pawn,queen等等)和棋子的位置,以及一个Move类,它包含了目标棋子,被移动棋子和被捕获棋子。

问题是,当我调用makeMove方法时,它将片段的位置更改为Piece对象内的方形目标。但是现在,我无法用Move对象调用unmakeMove,因为现在我没有关于移动来自哪里的信息,因为我刚刚更改了该部分的位置。你将如何解决这个问题?

非常感谢!

class Board: 
# Previous methods omitted. 

    def makeMove(self, move, player): 
     """ Makes a move on the board and changes Piece object. Returns None. """ 
     self.moved_piece = move.getPiece() 
     self.captured_piece = move.getCapturedPiece(self) 

     if self.captured_piece: # Remove captured piece from player's piece dict. 
      player.removePiece(self.captured_piece) 

     self.setPiece(move.getTargetSquare(), self.moved_piece) # Set moved piece on target square. 
     self.setPiece(self.moved_piece.getPosition(), EMPTY) # Make the origin square empty. 
     self.moved_piece.changePosition(move.getTargetSquare()) # Change piece object's position. 

    def unmakeMove(self, move, player): 
     """ Unmakes a move. Returns None. """ 
     self.moved_piece = move.getPiece() 
     self.captured_piece = move.getCapturedPiece(self) 

     self.setPiece(self.moved_piece.getPosition(), captured_piece) # Set captured piece or empty square to target square. 
     # Set piece to original square. HOW !? 
+5

你应该保留一个移动列表。这样,你可以将最后一步移出堆栈,做相反的事情,而你是金。你可能需要一个'reverseMove'方法和一个'uncapturePiece'方法。 – 2012-08-08 21:09:01

+3

阅读[纪念图案](http://en.wikipedia.org/wiki/Memento_pattern) – 2012-08-08 21:10:05

+0

@FredLarson:良好的联系。我以前不知道这一点。 – 2012-08-08 21:12:25

回答

2

基于我的评论和弗雷德·拉森贴link on the Memento pattern,这里是你可能想要做什么的范例:

class Engine(object): 
    def __init__(self): 
     self.board = Board() 
     self.move_list = [] 

    def make_move(self, from, to): 
     #board.makeMove returns a "memento object". 
     self.move_list.append(board.makeMove(from, to)) 
     ... 

    def undo_move(self): 
     board.undo(self.move_list.pop()) 
    ... 
    ... 

而且,我们说,你有这样的结构的移动对象:

class Move(object): 
    def __init__(self, from_coords, to_coords, capture=None): 
     self.from = from_coords 
     self.to = to_coords 
     self.capture = capture 

Board对象将实现以下方法:

class Board(object): 
    ... 
    def make_move(self, from_coords, to_coords): 
     #move logic here 
     return Move(from_coords, to_coords, capturedPiece) 

    def undo_move(self, move_object): 
     self.make_move(move_object.to_coords, move_object.from_coords) 
     self.uncapture(move_object.capture, move_object.to_coords) 

显然,上面的代码只是概念。实际的实现将取决于其他代码的结构。

注:我使用了Move对象的类,因为属性访问是明确的且易于遵循。实际上,一个像这样基本的对象可以简单地成为(from, to, capturedpiece)形式的元组。