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

[iæfai]

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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