Fw: a problem concerning a paper

[Jan Brosius]

> Hi,
>
> the paper is titled " lazy functional state-threads" .
>
> Under the topic "2.4 Encapsulation" consider the code
>
>     let v = runst (newVar True)
>     in
>     runST (readVar v)
>
> Consider the last line ; if the type of readVar v is say " MutVar s Bool"
> then readVar v will have type "ST s Bool".
> the article sais " s is free " . So my question is why hasn't readVar v
the
> type " forall s ( ST s Bool) " ?
>
> Thanks
>
> Jan Brosius
>
>