[Haskell-beginners] deducing type of multi-parameter type class

[Michael Snoyman]

On Thu, Jul 15, 2010 at 10:09 AM, Felipe Lessa <felipe.lessa at gmail.com>wrote:

> On Thu, Jul 15, 2010 at 3:13 AM, Michael Snoyman <michael at snoyman.com>
> wrote:
> > You could also use type families for this, but I believe you cannot
> express
> > the "Show" superclass:
> > class MyClass a where
> >     type MyResult a
> >     fn :: a -> MyResult a
>
> I guess this works:
>
> class Show (MyResult a) => MyClass a where
>   type MyResult a
>  fn :: a -> MyResult a
>

Thanks, I forgot about that. Funny, because I use it in Yesod ;).

Michael
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