Sun Yi Ming wrote:
Hello,
Hello,
this works fine, but i think if the two file are very big, and the readFile will consume too many mem.so i need to read the file line by line but stunned by the loop in IO Monad:
main = do h1 <- openFile "url1.txt" ReadMode h2 <- openFile "url2.txt" ReadMode line1 <- hGetLine h1 line2 <- hGetLine h2 print $ line1 : line2 : [] -- i don't howto do hClose h1 hClose h2
Don't worry about memory... GNU tools differs from unix-like systems: they don't utilizing IO by computing, they "slurp", or mmap entire file into memory and then process it. main = do h1 <- openFile "url1.lsm" h2 <- openFile "url2.lsm" print (zipFiles h1 h2) zipFiles :: Handle -> Handle -> IO [String] zipFiles h1 h2 = do eof1 <- hIsEOF h eof2 <- hIsEOF h case (eof1, eof2) of (False, False) -> do l1 <- hGetLine h1 l2 <- hGetLine h2 return l1:l2:(zipFiles h1 h2) (False, True) -> return (readFile h1) (True, False) -> return (readFile h2) _ -> [] I didn't tested it, but.... it should work... (I like fixed-width font and text-only mails... please, if you mail me, then send me only text, not html). Matej 'Yin' Gagyi