[Haskell-beginners] Empty 'do' constructor

[Brent Yorgey]

On Sat, Sep 25, 2010 at 01:43:33PM +0900, Sok H. Chang wrote:
> I use Haskell Platform 2010.2.0.0 on WinXP, and jEdit.
> I write my first code, and got error...
> 
> main = do cs <- readFile "C:\\SPR.txt"
> putStrLn $ myManupulation cs
> 
> myManupulation cs = (unlines cs) ! 3

Because putStrLn is not indented it is not considered part of the
do-block.  You should line it up under the stuff after the 'do',
like this:

  main = do cs <- readFile "C:\\SPR.txt"
            putStrLn $ myManupulation cs

-Brent