You can narrow down the problem by commenting out the part of the file that's giving you problems, and trying out the other functions in ghci. In your case, the main function is causing a parsing error. If you comment it out, you can verify that quicksort works correctly. Then look at your main function and see where it's broken. Try this out, and compare with what you wrote:

module Main (main) where

quicksort [] = []
quicksort (s:xs) = quicksort [x | x <- xs, x < s] ++ [s] ++ quicksort [x | x <- xs, x >= s]
main = do
  putStr "Ingrese la lista\n"
  line <- getLine
  let xs = read line :: [Int]
  print (quicksort xs)

-Peter

On Mon, Nov 7, 2011 at 3:41 PM, yrazes <yrazes@gmail.com> wrote:
Sorry, but I got this error while I compile it.

[yulys@yulys haskell]$ ghc -o quick quick.hs
[1 of 1] Compiling Main             ( quick.hs, quick.o )

quick.hs:7:11: parse error on input `<-'
[yulys@yulys haskell]$ 





On Mon, Nov 7, 2011 at 4:23 PM, KC <kc1956@gmail.com> wrote:
What is your question?



On Mon, Nov 7, 2011 at 9:45 AM, yrazes <yrazes@gmail.com> wrote:
> module Main (main) where
> quicksort [] = []
> quicksort (s:xs) = quicksort [x|x <- xs,x < s] ++ [s] ++ quicksort [x|x <-
> xs,x >= s]
> main = putStr "Ingrese la lista\n"
>        [xs] <- getLine
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe@haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
>



--
--
Regards,
KC


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