3 Nov
2010
3 Nov
'10
9:30 p.m.
On Tue, 2010-11-02 at 21:57 -0400, Brandon S Allbery KF8NH wrote:
On 10/29/10 09:35 , Dominique Devriese wrote:
* Only introduce a dependency from type class A to type class B if all functions in type class B can be implemented in terms of the functions in type class A or if type class A is empty.
Er? Eq a => Ord a makes perfect sense in context but violates this law.
x == y = case x `compare` y of EQ -> True; _ -> False Or using (==) inside definition: (==) = ((== EQ) .) . compare Class A - Ord, B - Eq. Regards