[Haskell-cafe] Re: [Haskell] A puzzle and an annoying feature
Lennart Augustsson
lennart at augustsson.net
Fri Nov 26 03:55:19 EST 2004
Martin Sulzmann wrote:
> [Discussion moved from Haskell to Haskell-Cafe]
>
> Hi,
>
> Regarding
>
> - "lazy overlap resolution" aka unique instances
>
> Well, if there's only instance which is not exported, then you can
> use functional dependencies.
>
> Assume
>
> class C a
> instance ... => C t
>
> Internally, use
>
> class C a | -> a
> instance ... => C t
>
But using functional dependencies feels like a sledge hammer,
and it is also not Haskell 98.
-- Lennart
More information about the Haskell-Cafe
mailing list