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  1. import Data.Maybe
  2. import Data.Char
  3. import Data.List
  4. import Data.String.Utils
  5. import Control.Applicative
  6.  
  7. data Piece = King  | Queen | Rook | Bishop | Knight | Pawn deriving(Eq,Enum,Show)
  8. data Actor = Black Piece | White Piece deriving(Eq)
  9. type Field = Maybe Actor
  10.  
  11. newtype Board = Board [Field]
  12.  
  13. instance Show Actor where
  14.     show (Black piece) = fmap toUpper $ show piece
  15.     show (White piece) = fmap toLower $ show piece
  16.  
  17. instance Show Board where
  18.     show (Board fields) = all $ split fields
  19.         where
  20.             all          = join "\n" . fmap rank . reverse
  21.             rank         = join "\t" . fmap (maybe "." show)
  22.             split []     = []
  23.             split fields = let (r,o)=splitAt 8 fields in r:split o
  24.  
  25. fenPiece :: Char -> Maybe Piece
  26. readFEN :: [Char] -> [Field]
  27.  
  28. fenPiece 'r' = Just Rook
  29. fenPiece 'b' = Just Bishop
  30. fenPiece 'n' = Just Knight
  31. fenPiece 'q' = Just Queen
  32. fenPiece 'k' = Just King
  33. fenPiece 'p' = Just Pawn
  34. fenPiece _   = Nothing
  35.  
  36. readFEN []             = []
  37. readFEN ('/':nextrank) = readFEN nextrank
  38. readFEN (piece:remain)
  39.     | piece `elem` "rbnqkp"   = (White <$> fenPiece piece)            : readFEN remain
  40.     | piece `elem` "RBNQKP"   = (Black <$> fenPiece (toLower piece))  : readFEN remain
  41.     | piece `elem` ['1'..'8'] = (replicate (read [piece]) $ Nothing) ++ readFEN remain
  42.     | otherwise = readFEN remain
  43.  
  44. main = do
  45.    putStrLn.show.Board $ readFEN "4r3/pp4k1/7p/n1p1p1p1/NbPpP2n/1P1P1r2/P1QB4/R4RK1"
  46.  
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin
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Standard input is empty
compilation info 
prog.hs:4:8:
    Could not find module `Data.String.Utils'
    Use -v to see a list of the files searched for.
stdout
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Standard output is empty
https://ideone.com/4RcIrD
language:
Haskell (ghc 8.4.4)
created:
12 years ago
visibility:
secret

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