Re: [Haskell-cafe] ST not strict enough?

2011/11/16 Johan Tibell :

On Wed, Nov 16, 2011 at 2:23 PM, Jason Dusek wrote:

...

Tried a modifySTRef' defined this way:

modifySTRef' ref f           =  do  val                       <-  (f $!!) <$> readSTRef ref  writeSTRef ref (val `seq` val)

...but there was no change in memory usage.

Why not just

    modifySTRef :: STRef s a -> (a -> a) -> ST s ()     modifySTRef ref f = do         x <- readSTRef ref         writeSTRef ref $! f x

(Note that I didn't check if modifySTRef was actually a problem in this case).

I just didn't want to miss an opportunity to put in extra strictness annotations! School of redundancy school. -- Jason Dusek () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments