Left-bias and non-structural equality.

[Christian Maeder]

Jean-Philippe Bernardy wrote:
> On 1/4/06, Christian Maeder <maeder at tzi.de> wrote:
>> I would not like to drop biasing distinction, as I don't think this
>> costs too much. With biasing, maps could be implemented via "biased
>> sets" (Set (MapEntry a b)):
>>
>> data MapEntry a b = a := b
>>
>> instance Eq/Ord a => Eq/Ord (MapEntry a b) where
>>     compare (a1 := _) (a2 := _) = compare a1 a2
> 
> I would discourage such a use. This is exaclty why we provide Maps, after all.

I still agree, but it might be nice to have for testing, comparison, and 
property specification purposes.

Christian