Question aboutthe use of an inner forall

Ashley Yakeley ashley@semantic.org
Fri, 16 Aug 2002 21:15:24 -0700


At 2002-08-16 20:57, Scott J. wrote:

>However what for heaven's sake should I think of
>
>runST :: forall a ( forall s ST s a) -> a ?

  runST :: forall a. ((forall s. ST s a) -> a)

"For all a, if (for all s, (ST s a)) then a."

You may apply runST to anything with a type of the form (forall s. ST s 
a), for any 'a'.


-- 
Ashley Yakeley, Seattle WA