Bracketeer.hs

import System.Environment

data Token = Token
    { row :: Int
    , col :: Int
    , val :: Char
    } deriving (Ord, Eq, Show)

tokenise :: String -> [Token]
tokenise = tok 1 1
  where
    tok _ _ [] = []
    tok row col ('\n':xs) = Token row col '\n' : tok (row+1) 1 xs
    tok row col (x:xs) = Token row col x : tok row (col+1) xs

unmatchedChars :: [Token] -> Char -> Char -> [Token]
unmatchedChars toks val1 val2 = stoks [] ftoks
  where
    ftoks = filter (\(Token _ _ v) -> v == val1 || v == val2) toks
    stoks s [] = s
    stoks ((Token _ _ val2):xs) ((Token _ _ val1):ts) = stoks xs ts
    stoks s (t:ts) = stoks (t : s) ts

processContents :: String -> String -> IO ()
processContents fname contents = do
    if null uB && null uP -- && null uA
        then return ()
        else putStrLn fname
    printResult uB
    printResult uP
    --printResult uA
  where
    match = unmatchedChars $ tokenise contents
    uB = match '{' '}'
    uP = match '(' ')'
    --uA = match '<' '>'
    printResult [] = return ()
    printResult result = mapM_ print result

processFile :: String -> IO ()
processFile fname = readFile fname >>= processContents fname

main :: IO ()
main = getArgs >>= mapM_ processFile