7 Apr
2006
7 Apr
'06
10:12 p.m.
On 4/7/06, Jared Updike
given an Ord instance (for a type T) a corresponding Eq instance can be given by:
instance Eq T where a == b = compare a b == EQ
where did this second -----^ == come from? (I guess if if Ordering derives Eq :-) I think you meant
instance (Ord T) => Eq T where a == b = case compare a b of EQ -> True _ -> False
Both work the same. Here's an intermediate form: a == b = if compare a b == EQ then True else False