Sigbjorn Finne wrote:
> forwarding to the mailing list is restricted to off-hours only at the
> moment, but thought I'd suggest a solution to you before then - use a
> (universally quantified) pattern matching function rather than a
> pattern binding, i.e.,
>
> deTIM :: TIM s a -> ST s a
> deTIM (TIM m) = m
>
> runTIM :: (forall s. TIM s a) -> Maybe a
> runTIM m = runST (deTIM m)
Thank you very much.
I thought I had tried this, but now I note that when I used the projection I
forgot to give the type signature for runTIM...
Maybe you could mention this problem its solution in the ghc manual section
about second order types.
--
OLAF CHITIL, Lehrstuhl fuer Informatik II, RWTH Aachen, 52056 Aachen, Germany
Tel: (+49/0)241/80-21212; Fax: (+49/0)241/8888-217
URL: http://www-i2.informatik.rwth-aachen.de/~chitil/
