Well I was going to say: import Data.Text.IO as T import Data.Enumerator.List as EL import Data.Enumerator.Text as ET run_ $ (ET.enumHandle fp $= ET.lines) $$ EL.mapM_ T.putStrLn for example. But it turns out this actually concatenates the lines together and prints one single string at the end. The reason is because it turns out that ET.enumHandle already gets lines one by one without you asking and it doesn't add newlines to the end, so ET.lines looks at each chunk and never sees any newlines so it returns the entire thing concatenated together figuring that was an entire line. I'm kind of surprised that enumHandle fetches linewise rather than to let you handle it. But if you were to make your own enumHandle that wasn't linewise that would work. On Mon, Jul 25, 2011 at 6:26 AM, Yves Parès <limestrael@gmail.com> wrote:
Okay, so there, the chunks (xs) will be lines of Text, and not just random blocks. Isn't there a primitive like printChunks in the enumerator library, or are we forced to handle Chunks and EOF by hand?
2011/7/25 David McBride <dmcbride@neondsl.com>
blah = do fp <- openFile "file" ReadMode run_ $ (ET.enumHandle fp $= ET.lines) $$ printChunks True
printChunks is super duper simple:
printChunks printEmpty = continue loop where loop (Chunks xs) = do let hide = null xs && not printEmpty CM.unless hide (liftIO (print xs)) continue loop
loop EOF = do liftIO (putStrLn "EOF") yield () EOF
Just replace print with whatever IO action you wanted to perform.
On Mon, Jul 25, 2011 at 4:31 AM, Yves Parès <limestrael@gmail.com> wrote:
Sorry, I'm only beginning to understand iteratees, but then how do you access each line of text output by the enumeratee "lines" within an iteratee?
2011/7/24 Felipe Almeida Lessa <felipe.lessa@gmail.com>
On Sun, Jul 24, 2011 at 12:28 PM, Yves Parès <limestrael@gmail.com> wrote:
If you used Data.Enumerator.Text, you would maybe benefit the "lines" function:
lines :: Monad m => Enumeratee Text Text m b
It gets arbitrary blocks of text and outputs lines of text.
But there is something I don't get with that signature: why isn't it: lines :: Monad m => Enumeratee Text [Text] m b ??
Lists of lines of text?
Cheers, =)
-- Felipe.
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe