Proposal: Add Data.List.sortNub and sortNubBy

[John Meacham]

On Wed, Mar 14, 2007 at 12:09:41AM +0000, Ian Lynagh wrote:
> On Tue, Mar 13, 2007 at 11:31:47PM +0000, Neil Mitchell wrote:
> > 
> > >    nubSorted :: Eq a => [a] -> [a]
> > >    nubSorted (x1:x2:xs)
> > >     | x1 == x2 = nubSorted (x1:xs)
> > >    nubSorted (x:xs) = x : nubSorted xs
> > >    nubSorted [] = []
> > 
> > I considered this, but nubSorted imposes a precondition, sortNub
> > ensures a postcondition. As an interface goes sortNub is harder to get
> > wrong.
> 
> That's all true, but I'd still prefer to have nubSorted than sortNub
> :-)

I dunno. I can't think of a common non-pathological operation that would
preserve sorting while adding duplicate elements. not that (map head .
group) won't ever come up... but i don't see how it could come up all
that often.

        John

-- 
John Meacham - ⑆repetae.net⑆john⑈