[Haskell-cafe] Question, re: type class syntax.

[William Yager]

If you want the "LogTree2" typeclass to have multiple type arguments (which
it looks like you do, from the definition of "evaluator"), you need to
define it as

class (Show a, Num a) => LogTree2 a t where

--Will

On Sat, Aug 29, 2015 at 6:45 PM, David Banas <capn.freako at gmail.com> wrote:

> Hi all,
>
> I can’t figure out why this is invalid:
>
> class (Show a, Num a) => LogTree2 a where
>     evaluator :: (LogTree2 a) t => t -> SizedVector a -> SizedVector a
>
> error| ‘LogTree2’ is applied to too many type arguments In the type
> ‘(LogTree2 a) t => t -> SizedVector a -> SizedVector a’ In the class
> declaration for ‘LogTree2’
>
> Can anyone help me understand?
>
> Thanks,
> -db
>
>
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