[Hugs-users] Network.CGI missing in Hugs
ross at soi.city.ac.uk
Wed Jan 10 18:21:07 EST 2007
On Wed, Jan 10, 2007 at 09:47:04PM -0000, Claus Reinke wrote:
> Bjorn Bringert wrote:
> >The bottom line is that the instance:
> >instance (MonadTrans t, MonadCGI m, Monad (t m)) => MonadCGI (t m) where
> >needs both overlapping and undecidable instances, doesn't work in
> >Hugs, and probably won't be Haskell'-compatible.
> but overlapping instances were also pioneered in Hugs!-)
> there are differences, eg, in how FDs combine with overlaps, or how scoped
> type variables in instances are interpreted, but Hugs has both unlimited
> and overlapping instances.
Yes, Hugs accepts this one with +o. Hugs does have additional
restrictions on overlapping instances that GHC defers to their point
of use, but this particular case is OK, because one of the overlapping
instances is a substitution instance of the other.
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