[Haskell-cafe] Is it safe to use unsafePerformIO here?

[Cristiano Paris]

On Thu, Sep 17, 2009 at 10:01 PM, Daniel Fischer
<daniel.is.fischer at web.de> wrote:
> ...
> readBit fn = do
>    txt <- readFile fn
>    let (l,_:bdy) = span (/= '\n') txt
>    return $ Bit (read l) bdy
>
> ?
>
> With
>
> main = do
>    args <- getArgs
>    let n = case args of
>                (a:_) -> read a
>                _ -> 1000
>    bl <- mapM readBit ["file1.txt","file2.txt"]
>    mapM_ (putStrLn . show . index) $ sortBy (comparing index) bl
>    mapM_ (putStrLn . take 20 . drop n . body) bl

Yes, it *seems* to work but... the files don't get closed (readFile is
unfinished until body is read) so I think I'm going to have problems
when the number of files to read is higher than the maximum number of
open handles a process can have.

That's a possibility I considered even if not directly using readFile.

Cristiano