perhaps

[Ashley Yakeley]

John Meacham wrote:
> does anyone else think this would be useful to provide?
> 
> 
>>module Data.Perhaps where
>>
>>data Perhaps = No | Maybe | Yes
>>        deriving(Eq,Ord,Show,Read,Enum,Bounded)
>>
>>instance Monoid Perhaps ...
>>...
> 
> 
> I only ask because it has come up as useful several times in projects I
> work on.

I think "Maybe Bool" is better for this. It already separates out for 
you the notion of certainty vs. uncertainty.

What Monoid did you have in mind for it?

-- 
Ashley Yakeley