Чтение файла, регулярные выражения

$alpha = [a-zA-Z]
$digit = [0-9]
$hex = [0-9a-fA-F]
$bin = [0-1]

import Text.Regex.Posix
 
sten1 :: String -> String -> Bool
sten1 test patt = test =~ patt
 
sten2 :: String -> String -> String
sten2 test patt = test =~ patt
 
sten3 :: String -> String -> (String,String,String)
sten3 test patt = test =~ patt

*Main> sten1 "foodiebar, fooquuxbar" "(foo[a-z]*bar|quux)"
True
it :: Bool
 
*Main> sten2 "foodiebar, fooquuxbar" "(foo[a-z]*bar|quux)"
"foodiebar"
it :: String
 
*Main> sten3 "foodiebar, fooquuxbar" "(foo[a-z]*bar|quux)"
("","foodiebar",", fooquuxbar")
it :: (String, String, String)

  build-depends:       base >= 4.7 && < 5
                      ,regex-posix

import System.IO
import System.Environment
import Text.Regex.Posix
 
sten1 :: String -> String -> Bool
sten1 test patt = test =~ patt
 
--sten2 :: String -> String -> String
--sten2 test patt = test =~ patt
 
--sten3 :: String -> String -> (String,String,String)
--sten3 test patt = test =~ patt
 
main = do
       (fnam:patt:etc) <- getArgs
       handle <- openFile fnam ReadMode
       contf <- hGetContents handle
       mapM putStrLn (filter (\ t -> (sten1 t patt)) (lines contf)) 
       hClose handle

main = do
       (fnam:patt:_) <- getArgs
       contf <- readFile fnam
       mapM putStrLn (filter (\ t -> (sten1 t patt)) (lines contf))

       (fnam:patt:_) <- getArgs

       let fnam = "inputfile.txt"
           patt = "(foo[a-z]*bar|quux)"