Re: [Haskell-beginners] Chessboard Module, opinions on…

[Andy Elvey]

Great!   Many thanks.... :)   

 - Andy

iæfai wrote:
> Andy, feel free. I should note that I am going to update this code to 
> use Text.PrettyPrint.HughesPJ shortly. In addition, it will be 
> cabalizing it and  go up on hackage once I figure it out.
>
> I will keep you informed of this.
>
> - iæfai
>
> On 2009-10-28, at 4:23 AM, Andy Elvey wrote:
>
>> iæfai wrote:
>>>
>>> I have just recently finished a 'ChessBoard' module that is meant to 
>>> represent a chess board. I could use some opinions and/or 
>>> suggestions on the module.
>>>
>>> To give an example of how this can be used right now, and was my 
>>> immediate goal, you can do this:
>>>
>>> *ChessBoard> putStr $ cout defaultBoard
>>> +----+----+----+----+----+----+----+----+
>>> | RB | NB | BB | QB | KB | BB | NB | RB |
>>> +----+----+----+----+----+----+----+----+
>>> | PB | PB | PB | PB | PB | PB | PB | PB |
>>> +----+----+----+----+----+----+----+----+
>>> |    |    |    |    |    |    |    |    |
>>> +----+----+----+----+----+----+----+----+
>>> |    |    |    |    |    |    |    |    |
>>> +----+----+----+----+----+----+----+----+
>>> |    |    |    |    |    |    |    |    |
>>> +----+----+----+----+----+----+----+----+
>>> |    |    |    |    |    |    |    |    |
>>> +----+----+----+----+----+----+----+----+
>>> | PW | PW | PW | PW | PW | PW | PW | PW |
>>> +----+----+----+----+----+----+----+----+
>>> | RW | NW | BW | QW | KW | BW | NW | RW |
>>> +----+----+----+----+----+----+----+----+
>>>
>>> I have not determined exactly how I will be making moves, but the 
>>> logic will not be in my program. I am going to be using a chess 
>>> engine in another process (I haven't chosen a chess engine yet that 
>>> works on both windows and mac through stdin/stdout).
>>>
>>> The module itself follows, I appreciate any thoughts you might have.
>>>
>>>
>>> module ChessBoard where
>>>
>>> import Data.Sequence
>>> import Data.Foldable
>>> import Data.Maybe
>>> import Data.List as List
>>>
>>> class NiceLook a where
>>>    cout :: a -> String
>>>
>>>
>>> data Piece = Bishop | Rook | Knight | King | Queen | Pawn | NoPiece
>>>    deriving (Show, Eq)
>>>
>>> instance NiceLook Piece where
>>>        cout Bishop = "B"
>>>        cout Rook   = "R"
>>>        cout Knight = "N"
>>>        cout Queen  = "Q"
>>>        cout Pawn   = "P"
>>>        cout King   = "K"
>>>        cout _      = " "
>>>
>>> data Colour = Black | White | NoColour
>>>    deriving (Show, Eq)
>>>
>>> instance NiceLook Colour where
>>>        cout Black = "B"
>>>        cout White = "W"
>>>        cout NoColour = " "
>>>
>>>        -- error "..." might be useful
>>>
>>> data Square = Square Piece Colour
>>>    deriving (Show, Eq)
>>>
>>> instance NiceLook (Square) where
>>>        cout (Square p c) = (cout p) ++ (cout c)
>>>
>>> data Row = Row (Seq Square)
>>>    deriving (Show, Eq)
>>>
>>> instance NiceLook (Row) where
>>>        cout (Row s) = "|" ++ foldMap (\x -> " " ++ cout x ++ " |") 
>>> s       -- thnx Saizan
>>>
>>> makeRow n = case (List.length n) of
>>>                8 -> Row (fromList n)
>>>                _ -> error "Row is not 8 squares"
>>>
>>> makeColouredSquares n c = makeRow $ map makeSquare (zip n (replicate 
>>> 8 c))
>>>
>>> makeSquare (n,c) = Square n c
>>>
>>> pawns = [Pawn, Pawn, Pawn, Pawn, Pawn, Pawn, Pawn, Pawn]
>>> back = [Rook, Knight, Bishop, Queen, King, Bishop, Knight, Rook]
>>> blank = [NoPiece, NoPiece, NoPiece, NoPiece, NoPiece, NoPiece, 
>>> NoPiece, NoPiece]
>>>
>>> data Board = Board (Seq Row)
>>>    deriving (Show, Eq)
>>>
>>> instance NiceLook (Board) where
>>>    cout (Board c) = borderOutput ++ "\n" ++ (foldMap (\x -> cout x 
>>> ++ "\n" ++ borderOutput ++ "\n") c)
>>>
>>> defaultBoard = Board (makeColouredSquares back Black <|
>>>                      makeColouredSquares pawns Black <|
>>>                      makeColouredSquares blank NoColour <|
>>>                      makeColouredSquares blank NoColour <|
>>>                      makeColouredSquares blank NoColour <|
>>>                      makeColouredSquares blank NoColour <|
>>>                      makeColouredSquares pawns White <|
>>>                      makeColouredSquares back White <| empty)
>>>
>>>
>>> borderOutput = "+" ++ (List.foldr1 (++) $ replicate 8 "----+")
>>>
>>>
>> Hi iæfai! This is great!  Very nicely done!
>> I was just wondering - I potter around with crosstab code in several 
>> programming languages, and this (the table-creation code in 
>> particular) could be quite handy in that area.  So, would you mind if 
>> I used this?  I'll give credit of course! Many thanks for posting 
>> this neat bit of code! - Andy
>>
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