[Haskell-cafe] ST not strict enough?

Yves Parès limestrael at gmail.com
Fri Nov 18 13:05:06 CET 2011

(Sorry for the double mail)
...so there is no way to do that inside the function passed to modifySTRef?
In other words, there is no way to ensure *inside* a function that its
result will be evaluated strictly?

2011/11/18 Daniel Fischer <daniel.is.fischer at googlemail.com>

> On Friday 18 November 2011, 11:18:33, Yves Parès wrote:
> > Instead of rewriting modifySTRef, why not just do :
> >
> > modifySTRef counter (\x -> let y = x+1 in y `seq` y)
> >
> > Is there a problem with that?
> Yes, y `seq` y is precisely the same as y.
> a `seq` b means whenever evaluation of b is demanded, also evaluate a (to
> WHNF).
> So y `seq` y ~> whenever evaluation of y is demanded, also evaluate y.
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