Re: [Haskell-beginners] University project - weird problem

Right now, my program is ike this listO = ['+', '-', '*', '/', '%', '^', '=', '>', '<', '.', '|', '&', '!', '~'] listS = [';', '{', '(', ')', '}', '[', ']', ','] listC = ['0','1'..'9'] listCF = listC ++ ['.'] listA = listO ++ listS ++ [' '] listPC = ["auto","double","int","struct","break","else","long","switch","case", "enum","register","typedef","char","extern","return","union","const", "float","short","unsigned","continue","for","signed","void","default", "goto","sizeof","volatile","do","if","static","while"] verifica :: IO () verifica = do putStr ("Favor visualizar o codigo para ver os bugs e erros do programa\n") putStr ("Digite o nome do arquivo de entrada: ") arqent <- getLine texto <- readFile arqent le_bloco texto le_bloco :: String -> IO () le_bloco (x:xs) | x `elem` listO = do operador (x:xs) | x `elem` listC = do cnum (x:xs) | x `elem` listS = do separador (x:xs) | x == '\n' = le_bloco xs | x == '"' = litstr (xs) | x /= ' ' = pchave (x:xs) [] | x == ' ' = le_bloco xs | otherwise = do { putStr "Outro\n" ; le_bloco xs } le_bloco [] = return () separador :: String -> IO () separador (x:xs) | x `elem` listS = do{ putStr [x] ; putStr " <separador>\n" ; le_bloco xs} cnum :: String -> IO () cnum (x:xs) | x `elem` listCF = do{ putChar x ; cnum xs} | otherwise = do{ putStr " \n" ; le_bloco (x:xs)} operador :: String -> IO () operador (x:xs) | x `elem` listO = do{ putChar x ; operador xs} | otherwise = do{ putStr " <operador>\n" ; le_bloco (x:xs)} litstr :: String -> IO () litstr (x:xs) | x /= '"' = do{ putChar x ; litstr xs} | otherwise = do{ putStr " <literal string>\n" ; le_bloco xs} pchave :: String -> String -> IO () pchave (x:xs) ys | x `notElem` listA = pchave xs (ys++[x]) | otherwise = pPCouI (x:xs) ys pPCouI :: String -> String -> IO () pPCouI (x:xs) z | membroPC z = do{ putStr (z ++ " <palavra chave>\n") ; le_bloco (x:xs)} | otherwise = do{putStr z ; putStr " <identificador>\n" ; le_bloco (x:xs)} membroPC :: String -> Bool membroPC x | x `elem` listPC = True | otherwise = False But there is still one problem that I haven't corrected: printing the tag when there is only one keyword or identifier in the line the case of beign the last one of the line is corrected but this one I don't know how to do