[Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem

[Jared Updike]

> I am trying to derive MyOrd class from Eq (Prelude):
>
> class Eq a => MyOrd a where
>         (%<=), (%>), (%>=) :: a -> a -> Bool
>         x %<= y = (x < y || x == y)
>         x %> y =  y < x
>         x %>= y = (y < x || x == y)
>
> Q: What's wrong?  Why 'Ord' gets into play here?

You are using < which is a function on types that instance the class
Ord, so the compiler is telling you to add (Ord a) to the same place
you have (Eq a) or don't use < or > or any function in the class Ord.
You can the prelude and thus the Ord class and make your own < and >
functions but you can't make them refer to the "real" < and >
functions without Ord because that is where they live.

  Jared.
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