HighestClose.hs

module HighestClose where
    import qualified Data.ByteString.Lazy.Char8 as L

    closing = readPrice . (!!7) . L.split ';'

    readPrice :: L.ByteString -> Maybe Int
    readPrice str = do
        (tl,rest) <- L.readInt str
        case rest of
            L.empty -> Nothing
            _ -> do
                (kurus,more) <- L.readInt (L.tail rest)
                return (tl * 100 + kurus)

    highestClose = maximum . (Nothing:) . map closing . L.lines

    highestCloseFrom path = do
        contents <- L.readFile path
        print (highestClose contents)