[Haskell-cafe] IO and lazyness.

D.V. dav.vire+haskell at gmail.com
Tue Mar 6 16:22:02 EST 2007

On 3/6/07, mm <schneegloeckchen at gmx.li> wrote:
> I cannot help you with your question more than pointing you to
> http://bugs.darcs.net/issue391
> where Simon Marlow explains how to avoid "IO.bracket".

I'm using Control.Exception's bracket.

Also, following Jeremy's advice, I replaced the last line of rechf2
with   return $! rech r $ lines f       and indeed it works.

I don't understand why it doesn't without the !

The documentation for hGetContents says the items are read on demand.
the function rech needs the strings so they should be read on demand.
This confuses me :(

More information about the Haskell-Cafe mailing list