[Haskell-beginners] How to manage typeclass hierarchies and instances?

PATRICK BROWNE patrick.browne at dit.ie
Sun Feb 22 07:53:12 UTC 2015


On 22 February 2015 at 00:04, Brandon Allbery <allbery.b at gmail.com> wrote:

> You can't, at present. (Note: Typeclasses are not OOP classes; `class (Num
> a, Group a) => Additive a` does not declare superclasses, but
> prerequisites.)
>

In logic we would say (Num a AND Group a) is a necessary condition for (
Additive a) => (Num a AND Group a) to hold.

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