[Haskell-beginners] Lazy file IO & Space leaks/waste

Nicolas Pouillard nicolas.pouillard at gmail.com
Fri Nov 6 04:25:22 EST 2009

Excerpts from Aleksandar Dimitrov's message of Thu Nov 05 12:01:11 +0100 2009:
> Hello list,
> I'm currently writing a small linguistic corpus analyzer. My input file is only
> 25MB, but profiling shows that the overall amount of allocation over the
> program's runtime is several GB. That's a little too much - adding to that is
> the fact that the program is abysmally slow, so I'm suspecting a space leak
> somewhere.
> I'm using the ByteString.Lazy.Char8 class in order to work efficiently with lazy
> IO and I must admit that I'm very inexperienced with predicting runtime and
> space behaviour of lazy IO :-( It worked well in the past, but I'm stuck now.
> The program can be found here:
> http://hpaste.org/fastcgi/hpaste.fcgi/view?id=11863#a11863

I've added a revision of your code and some highlights.
The main one is to suggest foldl' instead of foldr'. However without the input
text helping to improve is harder.

Nicolas Pouillard

More information about the Beginners mailing list