[Haskell-cafe] different behaviours with or without putStrLn

[Ben Foppa]

Depending on the kind of state, WHNF may not be enough - have you tried
with deepseq?


On Sun, Jan 12, 2014 at 5:07 PM, Corentin Dupont
<corentin.dupont at gmail.com>wrote:

> Hi guys,
> I'm experimenting different behaviours with or without a "putStrLn"! :(
>
> Basically, with the following code, I want the evaluation to really happen
> on the "evaluate".
> I found out that it doesn't: it is evaluated elsewhere (I don't know
> where).
> If I put a putStrLn (commented below), the evaluation really happens there.
>
>
>
>
>
>
>
> *execCommand :: (TVar MyState) -> StateT MyState IO () -> IO ()
> execCommand ts sm = do   s <- atomically $ readTVar ts   s' <- execStateT
> sm s   s'' <- evaluate s'          --evaluation should happen here, but it
> doesn't   --putStrLn $ displayMulti $ _multi s''    atomically $ writeTVar
> ts s''*
>
> To give you more context, I have a state that, when evaluated, might not
> terminate.
> So I added a watchdog (like in mueval), that will kill the thread in case
> the evaluation doesn't terminate.
> That's why I need to be sure of where the evaluation takes place.
>
> Thanks!
> Corentin
>
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20140112/a1b60016/attachment.html>